Patent Publication Number: US-11645309-B2

Title: Discovery of database and related services

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     The present disclosure is a continuation of U.S. patent application Ser. No. 16/228,267, filed Dec. 20, 2018, the entirety of which is incorporated by reference into the present disclosure. 
    
    
     BACKGROUND 
     Computing devices, software applications, and databases that make up a managed computer network may be discovered and representations thereof may be stored in a database in configuration items. The relationships between these configuration items may be discovered and stored in configuration items as well. The stored configuration items may later be retrieved and used to generate a visualization of a state or arrangement of components within the managed network. Discovering a computing device, database, or software application involves developing software processes that are capable of interacting with the devices, databases, or applications in order to gather information needed for detection, classification, and/or identification thereof. 
     SUMMARY 
     Discovery patterns may be used by a discovery application to identify computing devices, software applications, databases, and various other entities within a managed network. The discovery patterns may define rules and operations to be followed or executed by a discovery application in order to discover a particular entity. Discovery patterns may be tailored to, and thus configured to discover, specific types or versions of these entities. For example, a discovery pattern may be configured to discover a specific version of a particular software application released by a particular vendor or software product provider by accounting for the manner in which the particular software application stores and/or provides the information of interest in the discovery process. Thus, discovering multiple different software applications may necessitate multiple different discovery patterns, each tailored to the specific application sought to be discovered. 
     However, in some cases, a plurality of software applications may be communicatively connected by way of a software bus application. The software bus application may coordinate the communications of the plurality of software applications. For example, when some of the software applications utilize different communication protocols than others, the software bus application may facilitate communication therebetween by translating exchanged messages between the different communication protocols. Thus, the software bus may allow the software applications to communicate without needing to implement a single uniform communication protocol or standard or to support the protocols of other applications. 
     Since the software bus application is aware of each software application connected thereto, each of these software applications may be discoverable by way of the software bus application. That is, the embodiments herein described can replace or enhance discovery of individual software applications (e.g., discovering each of these software applications independently by using different, application-specific discovery patterns) by discovering the applications collectively based on data stored by the software bus application. 
     Accordingly, the discovery application may be configured to discover the software bus application, the server device on which it is installed, and any of the software applications that use the software bus. The discovery process of the software bus and the applications interconnected thereby may be defined or facilitated by a corresponding discovery pattern configured to collect the information needed for detection, classification, and mapping of aspects of the software bus application and the applications interconnected thereby. The discovery pattern may define, for example, software processes associated with the software bus application, directories in which the software bus stores files, files which contain information of interest, and commands configured to cause the software bus application to generate data of interest. Different discovery patterns may be available, each tailored to a different provider, type, or version of the software bus application. 
     Additionally, discovery patterns may be used independently of one another. That is, a discovery pattern tailored to a particular software application may be configured to discover the particular software application without relying on other discovery patterns or data gathered thereby. However, in some cases, different software products may coordinate with each other during operation, thereby exhibiting additional relationships. Such relationships might not be discoverable by using the respective discovery patterns for these products or applications independently. 
     One example where such additional relationships may be discoverable by using multiple discovery patterns, or the data gathered thereby, in combination involves the software bus application and a database manager. The database manager may coordinate multiple secondary databases that store data on behalf of the software bus application and/or the software applications interconnected thereby. Notably, information stored by the database manager may be used to discover the secondary databases, much like information stored by the software bus application is used to discover the software applications interconnected thereby. This approach may replace or enhance discovery of individual secondary databases by discovering the secondary databases collectively based on data stored by the database manager. 
     The software applications may communicate with the secondary databases by channeling communications through the software bus application and the database manager, rather than communicating with one another directly. Thus, discovery patterns used independently may be able to discover a communicative relationship between the software bus application and the database manager. For example, transmission of a network packet between the software bus and the database manager may indicate a communicative relationship. 
     However, the specific communicative relationships between the software applications and the secondary databases might not be discoverable in this manner. Namely, because the network packet is exchanged between the software bus and the database manager, rather than between a software application and a secondary database directly, the endpoints of this communication might not be apparent from information stored in the network packet. Rather, data in the network packet may be routed between the software bus and the applications, as well as between the database manager and the secondary databases, by internal communications that might not be readily visible. Alternatively, the data in this original network packet may be modified or adjusted by the software bus or the database manager before being sent on to the endpoint by way of a different network packet, which might not be readily mappable to the original network packet. 
     The software bus and the database manger may, however, track these internal communications and/or transformations of data between network packets. By correlating or mapping the communications generated and tracked by the software bus and the database manager, the discovery application may determine the specific secondary database and the specific software application between which a series of communications is exchanged. Thus, by using the discovery patterns for the software bus and the database manager in combination, the discovery application may map specific software applications to one or more corresponding secondary databases. 
     To that end, a discovery pattern for the database manager may be configured to cause the database manager to identify any modifications made to the secondary databases and the times at which these modifications took place. In some implementations, this information may be stored in catalogs associated with the secondary databases. Namely, a catalog of a particular secondary database may indicate the times at which the particular secondary database was accessed or modified. By correlating the access times and/or modification times of secondary databases with the times at which different network packets were transmitted to or received by the database manager, the discovery application may determine the particular software application that uses the particular secondary database. Such repeated correlation between the secondary databases and the software applications may allow for additional relationships to be discovered and existing relationships to be strengthened or validated. Notably, the catalogs of the secondary databases may be mapped to the database manager by the discovery application to indicate the communicate relationships therebetween. 
     Accordingly, a first example embodiment involves a computing system that includes a configuration management database (CMDB) disposed within a computational instance of a remote network management platform. The computational instance is associated with a managed network that includes a plurality of software applications communicatively connected by way of a software bus application. The computing system also includes a discovery application configured to obtain credentials for remotely accessing a server device that (i) is disposed in the managed network and (ii) hosts the software bus application. The discovery application is also configured to select, based on a pattern corresponding to the software bus application, one or more files to access and transmit, to the server device, instructions to access the one or more files. The discovery application is additionally configured to receive, from the server device, data identifying a plurality of attributes of the software bus application determined by accessing the one or more files. The discovery application is further configured to, based on the data identifying the plurality of attributes, transmit, to the server device, instructions to identify communicative connections established between the plurality of software applications by way of the software bus application and receive, from the server device, data identifying the communicative connections. The discovery application is yet further configured to, based on (i) the plurality of attributes and (ii) the communicative connections, generate a mapping that represents the communicative connections and store, in the CMDB, the mapping in one or more configuration items. 
     In a second example embodiment, a method includes obtaining, by a computing system associated with a remote network management platform that is associated with a managed network, credentials for remotely accessing a server device that (i) is disposed in the managed network and (ii) hosts a software bus application. The managed network includes a plurality of software applications communicatively connected by way of the software bus application. The method also includes selecting, by the computing system and based on a pattern corresponding to the software bus application, one or more files to access and transmitting, by the computing system and to the server device, instructions to access the one or more files. The method additionally includes receiving, by the computing system and from the server device, data identifying a plurality of attributes of the software bus application determined by accessing the one or more files. The method further includes, based on the data identifying the plurality of attributes, transmitting, by the computing system and to the server device, instructions to identify communicative connections established between the plurality of software applications by way of the software bus application, and receiving, by the computing system and from the server device, data identifying the communicative connections. The method yet further includes, based on (i) the plurality of attributes and (ii) the communicative connections, generating, by the computing system, a mapping that represents the communicative connections and storing, in a CMDB disposed within the remote network management platform, the mapping in one or more configuration items. 
     In a third example embodiment, an article of manufacture may include a non-transitory computer-readable medium, having stored thereon program instructions that, upon execution by a computing system, cause the computing system to perform operations in accordance with the second example embodiment. 
     In a fourth example embodiment, a computing system may include at least one processor, as well as memory and program instructions. The program instructions may be stored in the memory, and upon execution by the at least one processor, cause the computing system to perform operations in accordance with the second example embodiment. 
     In a fifth example embodiment, a system may include various means for carrying out each of the operations of the second example embodiment. 
     In a sixth example embodiment, a computing system includes a configuration management database (CMDB) disposed within a computational instance of a remote network management platform. The computational instance is associated with a managed network. The managed network includes a database manager hosted on a server device. The database manager is configured to manage one or more secondary databases that are configured to store data for software applications executable by the managed network. The computing system also includes a discovery application configured to perform operations. The operations include identifying a type of the database manager by causing the server device to execute a command configured to cause the database manager to identify the type thereof. The operations also include selecting, based on a pattern corresponding to the type of the database manager, one or more additional commands. The operations additionally include determining respective database catalogs of the one or more secondary databases by (i) causing the server device to execute the one or more additional commands and (ii) receiving, from the server device, data identifying the respective database catalogs of the one or more secondary databases. Each database catalog identifies a structure of a corresponding secondary database of the one or more secondary databases. The operations further include generating, based on the received data, a mapping between the database manager and each of the respective database catalogs of the one or more secondary databases. The operations yet further include storing, in the CMDB, the generated mapping in one or more configuration items. 
     In a seventh example embodiment, a method includes identifying, by a computing system, a type of a database manager hosted by a server device associated with a managed network. The database manager is configured to manage one or more secondary databases that are configured to store data for software applications executable by the managed network. Identifying the type of the database manager involves causing the server device to execute a command configured to cause the database manager to identifying the type thereof. The method also includes selecting, by the computing system and based on a pattern corresponding to the type of the database manager, one or more additional commands. The method additionally includes determining, by the computing system, respective database catalogs of the one or more secondary databases by (i) causing the server device to execute the one or more additional commands and (ii) receiving, from the server device, data identifying the respective database catalogs of the one or more secondary databases. Each database catalog identifies a structure of a corresponding secondary database of the one or more secondary databases. The method further includes generating, by the computing system and based on the received data, a mapping between the database manager and each of the respective database catalogs of the one or more secondary databases. The method yet further includes storing, in a CMDB that is associated with the managed network and disposed within a computational instance of a remote network management platform, the generated mapping as one or more configuration items. 
     In an eighth example embodiment, an article of manufacture may include a non-transitory computer-readable medium, having stored thereon program instructions that, upon execution by a computing system, cause the computing system to perform operations in accordance with the seventh example embodiment. 
     In a ninth example embodiment, a computing system may include at least one processor, as well as memory and program instructions. The program instructions may be stored in the memory, and upon execution by the at least one processor, cause the computing system to perform operations in accordance with the seventh example embodiment. 
     In a tenth example embodiment, a system may include various means for carrying out each of the operations of the seventh example embodiment. 
     These as well as other embodiments, aspects, advantages, and alternatives will become apparent to those of ordinary skill in the art by reading the following detailed description, with reference where appropriate to the accompanying drawings. Further, this summary and other descriptions and figures provided herein are intended to illustrate embodiments by way of example only and, as such, that numerous variations are possible. For instance, structural elements and process steps can be rearranged, combined, distributed, eliminated, or otherwise changed, while remaining within the scope of the embodiments as claimed. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG.  1    illustrates a schematic drawing of a computing device, in accordance with example embodiments. 
         FIG.  2    illustrates a schematic drawing of a server device cluster, in accordance with example embodiments. 
         FIG.  3    depicts a remote network management architecture, in accordance with example embodiments. 
         FIG.  4    depicts a communication environment involving a remote network management architecture, in accordance with example embodiments. 
         FIG.  5 A  depicts another communication environment involving a remote network management architecture, in accordance with example embodiments. 
         FIG.  5 B  is a flow chart, in accordance with example embodiments. 
         FIG.  6    depicts a software bus application, in accordance with example embodiments. 
         FIG.  7    depicts a message flow diagram, in accordance with example embodiments. 
         FIG.  8    depicts a database manager, in accordance with example embodiments. 
         FIG.  9    depicts a message flow diagram, in accordance with example embodiments. 
         FIG.  10    is a flow chart, in accordance with example embodiments. 
         FIG.  11    is a flow chart, in accordance with example embodiments. 
     
    
    
     DETAILED DESCRIPTION 
     Example methods, devices, and systems are described herein. It should be understood that the words “example” and “exemplary” are used herein to mean “serving as an example, instance, or illustration.” Any embodiment or feature described herein as being an “example” or “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments or features unless stated as such. Thus, other embodiments can be utilized and other changes can be made without departing from the scope of the subject matter presented herein. 
     Accordingly, the example embodiments described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations. For example, the separation of features into “client” and “server” components may occur in a number of ways. 
     Further, unless context suggests otherwise, the features illustrated in each of the figures may be used in combination with one another. Thus, the figures should be generally viewed as component aspects of one or more overall embodiments, with the understanding that not all illustrated features are necessary for each embodiment. 
     Additionally, any enumeration of elements, blocks, or steps in this specification or the claims is for purposes of clarity. Thus, such enumeration should not be interpreted to require or imply that these elements, blocks, or steps adhere to a particular arrangement or are carried out in a particular order. 
     I. Introduction 
     A large enterprise is a complex entity with many interrelated operations. Some of these are found across the enterprise, such as human resources (HR), supply chain, information technology (IT), and finance. However, each enterprise also has its own unique operations that provide essential capabilities and/or create competitive advantages. 
     To support widely-implemented operations, enterprises typically use off-the-shelf software applications, such as customer relationship management (CRM) and human capital management (HCM) packages. However, they may also need custom software applications to meet their own unique requirements. A large enterprise often has dozens or hundreds of these custom software applications. Nonetheless, the advantages provided by the embodiments herein are not limited to large enterprises and may be applicable to an enterprise, or any other type of organization, of any size. 
     Many such software applications are developed by individual departments within the enterprise. These range from simple spreadsheets to custom-built software tools and databases. But the proliferation of siloed custom software applications has numerous disadvantages. It negatively impacts an enterprise&#39;s ability to run and grow its operations, innovate, and meet regulatory requirements. The enterprise may find it difficult to integrate, streamline and enhance its operations due to lack of a single system that unifies its subsystems and data. 
     To efficiently create custom applications, enterprises would benefit from a remotely-hosted application platform that eliminates unnecessary development complexity. The goal of such a platform would be to reduce time-consuming, repetitive application development tasks so that software engineers and individuals in other roles can focus on developing unique, high-value features. 
     In order to achieve this goal, the concept of Application Platform as a Service (aPaaS) is introduced, to intelligently automate workflows throughout the enterprise. An aPaaS system is hosted remotely from the enterprise, but may access data, applications, and services within the enterprise by way of secure connections. Such an aPaaS system may have a number of advantageous capabilities and characteristics. These advantages and characteristics may be able to improve the enterprise&#39;s operations and workflow for IT, HR, CRM, customer service, application development, and security. 
     The aPaaS system may support development and execution of model-view-controller (MVC) applications. MVC applications divide their functionality into three interconnected parts (model, view, and controller) in order to isolate representations of information from the manner in which the information is presented to the user, thereby allowing for efficient code reuse and parallel development. These applications may be web-based, and offer create, read, update, delete (CRUD) capabilities. This allows new applications to be built on a common application infrastructure. 
     The aPaaS system may support standardized application components, such as a standardized set of widgets for graphical user interface (GUI) development. In this way, applications built using the aPaaS system have a common look and feel. Other software components and modules may be standardized as well. In some cases, this look and feel can be branded or skinned with an enterprise&#39;s custom logos and/or color schemes. 
     The aPaaS system may support the ability to configure the behavior of applications using metadata. This allows application behaviors to be rapidly adapted to meet specific needs. Such an approach reduces development time and increases flexibility. Further, the aPaaS system may support GUI tools that facilitate metadata creation and management, thus reducing errors in the metadata. 
     The aPaaS system may support clearly-defined interfaces between applications, so that software developers can avoid unwanted inter-application dependencies. Thus, the aPaaS system may implement a service layer in which persistent state information and other data is stored. 
     The aPaaS system may support a rich set of integration features so that the applications thereon can interact with legacy applications and third-party applications. For instance, the aPaaS system may support a custom employee-onboarding system that integrates with legacy HR, IT, and accounting systems. 
     The aPaaS system may support enterprise-grade security. Furthermore, since the aPaaS system may be remotely hosted, it should also utilize security procedures when it interacts with systems in the enterprise or third-party networks and services hosted outside of the enterprise. For example, the aPaaS system may be configured to share data amongst the enterprise and other parties to detect and identify common security threats. 
     Other features, functionality, and advantages of an aPaaS system may exist. This description is for purpose of example and is not intended to be limiting. 
     As an example of the aPaaS development process, a software developer may be tasked to create a new application using the aPaaS system. First, the developer may define the data model, which specifies the types of data that the application uses and the relationships therebetween. Then, via a GUI of the aPaaS system, the developer enters (e.g., uploads) the data model. The aPaaS system automatically creates all of the corresponding database tables, fields, and relationships, which can then be accessed via an object-oriented services layer. 
     In addition, the aPaaS system can also build a fully-functional MVC application with client-side interfaces and server-side CRUD logic. This generated application may serve as the basis of further development for the user. Advantageously, the developer does not have to spend a large amount of time on basic application functionality. Further, since the application may be web-based, it can be accessed from any Internet-enabled client device. Alternatively or additionally, a local copy of the application may be able to be accessed, for instance, when Internet service is not available. 
     The aPaaS system may also support a rich set of pre-defined functionality that can be added to applications. These features include support for searching, email, templating, workflow design, reporting, analytics, social media, scripting, mobile-friendly output, and customized GUIs. 
     The following embodiments describe architectural and functional aspects of example aPaaS systems, as well as the features and advantages thereof. 
     II. Example Computing Devices and Cloud-Based Computing Environments 
       FIG.  1    is a simplified block diagram exemplifying a computing device  100 , illustrating some of the components that could be included in a computing device arranged to operate in accordance with the embodiments herein. Computing device  100  could be a client device (e.g., a device actively operated by a user), a server device (e.g., a device that provides computational services to client devices), or some other type of computational platform. Some server devices may operate as client devices from time to time in order to perform particular operations, and some client devices may incorporate server features. 
     In this example, computing device  100  includes processor  102 , memory  104 , network interface  106 , and an input/output unit  108 , all of which may be coupled by a system bus  110  or a similar mechanism. In some embodiments, computing device  100  may include other components and/or peripheral devices (e.g., detachable storage, printers, and so on). 
     Processor  102  may be one or more of any type of computer processing element, such as a central processing unit (CPU), a co-processor (e.g., a mathematics, graphics, or encryption co-processor), a digital signal processor (DSP), a network processor, and/or a form of integrated circuit or controller that performs processor operations. In some cases, processor  102  may be one or more single-core processors. In other cases, processor  102  may be one or more multi-core processors with multiple independent processing units. Processor  102  may also include register memory for temporarily storing instructions being executed and related data, as well as cache memory for temporarily storing recently-used instructions and data. 
     Memory  104  may be any form of computer-usable memory, including but not limited to random access memory (RAM), read-only memory (ROM), and non-volatile memory (e.g., flash memory, hard disk drives, solid state drives, compact discs (CDs), digital video discs (DVDs), and/or tape storage). Thus, memory  104  represents both main memory units, as well as long-term storage. Other types of memory may include biological memory. 
     Memory  104  may store program instructions and/or data on which program instructions may operate. By way of example, memory  104  may store these program instructions on a non-transitory, computer-readable medium, such that the instructions are executable by processor  102  to carry out any of the methods, processes, or operations disclosed in this specification or the accompanying drawings. 
     As shown in  FIG.  1   , memory  104  may include firmware  104 A, kernel  104 B, and/or applications  104 C. Firmware  104 A may be program code used to boot or otherwise initiate some or all of computing device  100 . Kernel  104 B may be an operating system, including modules for memory management, scheduling and management of processes, input/output, and communication. Kernel  104 B may also include device drivers that allow the operating system to communicate with the hardware modules (e.g., memory units, networking interfaces, ports, and busses), of computing device  100 . Applications  104 C may be one or more user-space software programs, such as web browsers or email clients, as well as any software libraries used by these programs. Memory  104  may also store data used by these and other programs and applications. 
     Network interface  106  may take the form of one or more wireline interfaces, such as Ethernet (e.g., Fast Ethernet, Gigabit Ethernet, and so on). Network interface  106  may also support communication over one or more non-Ethernet media, such as coaxial cables or power lines, or over wide-area media, such as Synchronous Optical Networking (SONET) or digital subscriber line (DSL) technologies. Network interface  106  may additionally take the form of one or more wireless interfaces, such as IEEE 802.11 (Wifi), BLUETOOTH®, global positioning system (GPS), or a wide-area wireless interface. However, other forms of physical layer interfaces and other types of standard or proprietary communication protocols may be used over network interface  106 . Furthermore, network interface  106  may comprise multiple physical interfaces. For instance, some embodiments of computing device  100  may include Ethernet, BLUETOOTH®, and Wifi interfaces. 
     Input/output unit  108  may facilitate user and peripheral device interaction with example computing device  100 . Input/output unit  108  may include one or more types of input devices, such as a keyboard, a mouse, a touch screen, and so on. Similarly, input/output unit  108  may include one or more types of output devices, such as a screen, monitor, printer, and/or one or more light emitting diodes (LEDs). Additionally or alternatively, computing device  100  may communicate with other devices using a universal serial bus (USB) or high-definition multimedia interface (HDMI) port interface, for example. 
     In some embodiments, one or more instances of computing device  100  may be deployed to support an aPaaS architecture. The exact physical location, connectivity, and configuration of these computing devices may be unknown and/or unimportant to client devices. Accordingly, the computing devices may be referred to as “cloud-based” devices that may be housed at various remote data center locations. 
       FIG.  2    depicts a cloud-based server cluster  200  in accordance with example embodiments. In  FIG.  2   , operations of a computing device (e.g., computing device  100 ) may be distributed between server devices  202 , data storage  204 , and routers  206 , all of which may be connected by local cluster network  208 . The number of server devices  202 , data storages  204 , and routers  206  in server cluster  200  may depend on the computing task(s) and/or applications assigned to server cluster  200 . 
     For example, server devices  202  can be configured to perform various computing tasks of computing device  100 . Thus, computing tasks can be distributed among one or more of server devices  202 . To the extent that these computing tasks can be performed in parallel, such a distribution of tasks may reduce the total time to complete these tasks and return a result. For purpose of simplicity, both server cluster  200  and individual server devices  202  may be referred to as a “server device.” This nomenclature should be understood to imply that one or more distinct server devices, data storage devices, and cluster routers may be involved in server device operations. 
     Data storage  204  may be data storage arrays that include drive array controllers configured to manage read and write access to groups of hard disk drives and/or solid state drives. The drive array controllers, alone or in conjunction with server devices  202 , may also be configured to manage backup or redundant copies of the data stored in data storage  204  to protect against drive failures or other types of failures that prevent one or more of server devices  202  from accessing units of data storage  204 . Other types of memory aside from drives may be used. 
     Routers  206  may include networking equipment configured to provide internal and external communications for server cluster  200 . For example, routers  206  may include one or more packet-switching and/or routing devices (including switches and/or gateways) configured to provide (i) network communications between server devices  202  and data storage  204  via local cluster network  208 , and/or (ii) network communications between the server cluster  200  and other devices via communication link  210  to network  212 . 
     Additionally, the configuration of routers  206  can be based at least in part on the data communication requirements of server devices  202  and data storage  204 , the latency and throughput of the local cluster network  208 , the latency, throughput, and cost of communication link  210 , and/or other factors that may contribute to the cost, speed, fault-tolerance, resiliency, efficiency and/or other design goals of the system architecture. 
     As a possible example, data storage  204  may include any form of database, such as a structured query language (SQL) database. Various types of data structures may store the information in such a database, including but not limited to tables, arrays, lists, trees, and tuples. Furthermore, any databases in data storage  204  may be monolithic or distributed across multiple physical devices. 
     Server devices  202  may be configured to transmit data to and receive data from data storage  204 . This transmission and retrieval may take the form of SQL queries or other types of database queries, and the output of such queries, respectively. Additional text, images, video, and/or audio may be included as well. Furthermore, server devices  202  may organize the received data into web page representations. Such a representation may take the form of a markup language, such as the hypertext markup language (HTML), the extensible markup language (XML), or some other standardized or proprietary format. Moreover, server devices  202  may have the capability of executing various types of computerized scripting languages, such as but not limited to Perl, Python, PHP Hypertext Preprocessor (PHP), Active Server Pages (ASP), JavaScript, and so on. Computer program code written in these languages may facilitate the providing of web pages to client devices, as well as client device interaction with the web pages. 
     III. Example Remote Network Management Architecture 
       FIG.  3    depicts a remote network management architecture, in accordance with example embodiments. This architecture includes three main components, managed network  300 , remote network management platform  320 , and third-party networks  340 , all connected by way of Internet  350 . 
     Managed network  300  may be, for example, an enterprise network used by an entity for computing and communications tasks, as well as storage of data. Thus, managed network  300  may include various client devices  302 , server devices  304 , routers  306 , virtual machines  308 , firewall  310 , and/or proxy servers  312 . Client devices  302  may be embodied by computing device  100 , server devices  304  may be embodied by computing device  100  or server cluster  200 , and routers  306  may be any type of router, switch, or gateway. 
     Virtual machines  308  may be embodied by one or more of computing device  100  or server cluster  200 . In general, a virtual machine is an emulation of a computing system, and mimics the functionality (e.g., processor, memory, and communication resources) of a physical computer. One physical computing system, such as server cluster  200 , may support up to thousands of individual virtual machines. In some embodiments, virtual machines  308  may be managed by a centralized server device or application that facilitates allocation of physical computing resources to individual virtual machines, as well as performance and error reporting. Enterprises often employ virtual machines in order to allocate computing resources in an efficient, as needed fashion. Providers of virtualized computing systems include VMWARE® and MICROSOFT®. 
     Firewall  310  may be one or more specialized routers or server devices that protect managed network  300  from unauthorized attempts to access the devices, applications, and services therein, while allowing authorized communication that is initiated from managed network  300 . Firewall  310  may also provide intrusion detection, web filtering, virus scanning, application-layer gateways, and other applications or services. In some embodiments not shown in  FIG.  3   , managed network  300  may include one or more virtual private network (VPN) gateways with which it communicates with remote network management platform  320  (see below). 
     Managed network  300  may also include one or more proxy servers  312 . An embodiment of proxy servers  312  may be a server device that facilitates communication and movement of data between managed network  300 , remote network management platform  320 , and third-party networks  340 . In particular, proxy servers  312  may be able to establish and maintain secure communication sessions with one or more computational instances of remote network management platform  320 . By way of such a session, remote network management platform  320  may be able to discover and manage aspects of the architecture and configuration of managed network  300  and its components. Possibly with the assistance of proxy servers  312 , remote network management platform  320  may also be able to discover and manage aspects of third-party networks  340  that are used by managed network  300 . 
     Firewalls, such as firewall  310 , typically deny all communication sessions that are incoming by way of Internet  350 , unless such a session was ultimately initiated from behind the firewall (i.e., from a device on managed network  300 ) or the firewall has been explicitly configured to support the session. By placing proxy servers  312  behind firewall  310  (e.g., within managed network  300  and protected by firewall  310 ), proxy servers  312  may be able to initiate these communication sessions through firewall  310 . Thus, firewall  310  might not have to be specifically configured to support incoming sessions from remote network management platform  320 , thereby avoiding potential security risks to managed network  300 . 
     In some cases, managed network  300  may consist of a few devices and a small number of networks. In other deployments, managed network  300  may span multiple physical locations and include hundreds of networks and hundreds of thousands of devices. Thus, the architecture depicted in  FIG.  3    is capable of scaling up or down by orders of magnitude. 
     Furthermore, depending on the size, architecture, and connectivity of managed network  300 , a varying number of proxy servers  312  may be deployed therein. For example, each one of proxy servers  312  may be responsible for communicating with remote network management platform  320  regarding a portion of managed network  300 . Alternatively or additionally, sets of two or more proxy servers may be assigned to such a portion of managed network  300  for purposes of load balancing, redundancy, and/or high availability. 
     Remote network management platform  320  is a hosted environment that provides aPaaS services to users, particularly to the operators of managed network  300 . These services may take the form of web-based portals, for instance. Thus, a user can securely access remote network management platform  320  from, for instance, client devices  302 , or potentially from a client device outside of managed network  300 . By way of the web-based portals, users may design, test, and deploy applications, generate reports, view analytics, and perform other tasks. 
     As shown in  FIG.  3   , remote network management platform  320  includes four computational instances  322 ,  324 ,  326 , and  328 . Each of these instances may represent a set of web portals, services, and applications (e.g., a wholly-functioning aPaaS system) available to a particular customer. In some cases, a single customer may use multiple computational instances. For example, managed network  300  may be an enterprise customer of remote network management platform  320 , and may use computational instances  322 ,  324 , and  326 . The reason for providing multiple instances to one customer is that the customer may wish to independently develop, test, and deploy its applications and services. Thus, computational instance  322  may be dedicated to application development related to managed network  300 , computational instance  324  may be dedicated to testing these applications, and computational instance  326  may be dedicated to the live operation of tested applications and services. A computational instance may also be referred to as a hosted instance, a remote instance, a customer instance, or by some other designation. Any application deployed onto a computational instance may be a scoped application, in that its access to databases within the computational instance can be restricted to certain elements therein (e.g., one or more particular database tables or particular rows with one or more database tables). 
     The multi-instance architecture of remote network management platform  320  is in contrast to conventional multi-tenant architectures, over which multi-instance architectures have several advantages. In multi-tenant architectures, data from different customers (e.g., enterprises) are comingled in a single database. While these customers&#39; data are separate from one another, the separation is enforced by the software that operates the single database. As a consequence, a security breach in this system may impact all customers&#39; data, creating additional risk, especially for entities subject to governmental, healthcare, and/or financial regulation. Furthermore, any database operations that impact one customer will likely impact all customers sharing that database. Thus, if there is an outage due to hardware or software errors, this outage affects all such customers. Likewise, if the database is to be upgraded to meet the needs of one customer, it will be unavailable to all customers during the upgrade process. Often, such maintenance windows will be long, due to the size of the shared database. 
     In contrast, the multi-instance architecture provides each customer with its own database in a dedicated computing instance. This prevents comingling of customer data, and allows each instance to be independently managed. For example, when one customer&#39;s instance experiences an outage due to errors or an upgrade, other computational instances are not impacted. Maintenance down time is limited because the database only contains one customer&#39;s data. Further, the simpler design of the multi-instance architecture allows redundant copies of each customer database and instance to be deployed in a geographically diverse fashion. This facilitates high availability, where the live version of the customer&#39;s instance can be moved when faults are detected or maintenance is being performed. 
     In some embodiments, remote network management platform  320  may include one or more central instances, controlled by the entity that operates this platform. Like a computational instance, a central instance may include some number of physical or virtual servers and database devices. Such a central instance may serve as a repository for data that can be shared amongst at least some of the computational instances. For instance, definitions of common security threats that could occur on the computational instances, software packages that are commonly discovered on the computational instances, and/or an application store for applications that can be deployed to the computational instances may reside in a central instance. Computational instances may communicate with central instances by way of well-defined interfaces in order to obtain this data. 
     In order to support multiple computational instances in an efficient fashion, remote network management platform  320  may implement a plurality of these instances on a single hardware platform. For example, when the aPaaS system is implemented on a server cluster such as server cluster  200 , it may operate a virtual machine that dedicates varying amounts of computational, storage, and communication resources to instances. But full virtualization of server cluster  200  might not be necessary, and other mechanisms may be used to separate instances. In some examples, each instance may have a dedicated account and one or more dedicated databases on server cluster  200 . Alternatively, computational instance  322  may span multiple physical devices. 
     In some cases, a single server cluster of remote network management platform  320  may support multiple independent enterprises. Furthermore, as described below, remote network management platform  320  may include multiple server clusters deployed in geographically diverse data centers in order to facilitate load balancing, redundancy, and/or high availability. 
     Third-party networks  340  may be remote server devices (e.g., a plurality of server clusters such as server cluster  200 ) that can be used for outsourced computational, data storage, communication, and service hosting operations. These servers may be virtualized (i.e., the servers may be virtual machines). Examples of third-party networks  340  may include AMAZON WEB SERVICES® and MICROSOFT® Azure. Like remote network management platform  320 , multiple server clusters supporting third-party networks  340  may be deployed at geographically diverse locations for purposes of load balancing, redundancy, and/or high availability. 
     Managed network  300  may use one or more of third-party networks  340  to deploy applications and services to its clients and customers. For instance, if managed network  300  provides online music streaming services, third-party networks  340  may store the music files and provide web interface and streaming capabilities. In this way, the enterprise of managed network  300  does not have to build and maintain its own servers for these operations. 
     Remote network management platform  320  may include modules that integrate with third-party networks  340  to expose virtual machines and managed services therein to managed network  300 . The modules may allow users to request virtual resources and provide flexible reporting for third-party networks  340 . In order to establish this functionality, a user from managed network  300  might first establish an account with third-party networks  340 , and request a set of associated resources. Then, the user may enter the account information into the appropriate modules of remote network management platform  320 . These modules may then automatically discover the manageable resources in the account, and also provide reports related to usage, performance, and billing. 
     Internet  350  may represent a portion of the global Internet. However, Internet  350  may alternatively represent a different type of network, such as a private wide-area or local-area packet-switched network. 
       FIG.  4    further illustrates the communication environment between managed network  300  and computational instance  322 , and introduces additional features and alternative embodiments. In  FIG.  4   , computational instance  322  is replicated across data centers  400 A and  400 B. These data centers may be geographically distant from one another, perhaps in different cities or different countries. Each data center includes support equipment that facilitates communication with managed network  300 , as well as remote users. 
     In data center  400 A, network traffic to and from external devices flows either through VPN gateway  402 A or firewall  404 A. VPN gateway  402 A may be peered with VPN gateway  412  of managed network  300  by way of a security protocol such as Internet Protocol Security (IPSEC) or Transport Layer Security (TLS). Firewall  404 A may be configured to allow access from authorized users, such as user  414  and remote user  416 , and to deny access to unauthorized users. By way of firewall  404 A, these users may access computational instance  322 , and possibly other computational instances. Load balancer  406 A may be used to distribute traffic amongst one or more physical or virtual server devices that host computational instance  322 . Load balancer  406 A may simplify user access by hiding the internal configuration of data center  400 A, (e.g., computational instance  322 ) from client devices. For instance, if computational instance  322  includes multiple physical or virtual computing devices that share access to multiple databases, load balancer  406 A may distribute network traffic and processing tasks across these computing devices and databases so that no one computing device or database is significantly busier than the others. In some embodiments, computational instance  322  may include VPN gateway  402 A, firewall  404 A, and load balancer  406 A. 
     Data center  400 B may include its own versions of the components in data center  400 A. Thus, VPN gateway  402 B, firewall  404 B, and load balancer  406 B may perform the same or similar operations as VPN gateway  402 A, firewall  404 A, and load balancer  406 A, respectively. Further, by way of real-time or near-real-time database replication and/or other operations, computational instance  322  may exist simultaneously in data centers  400 A and  400 B. 
     Data centers  400 A and  400 B as shown in  FIG.  4    may facilitate redundancy and high availability. In the configuration of  FIG.  4   , data center  400 A is active and data center  400 B is passive. Thus, data center  400 A is serving all traffic to and from managed network  300 , while the version of computational instance  322  in data center  400 B is being updated in near-real-time. Other configurations, such as one in which both data centers are active, may be supported. 
     Should data center  400 A fail in some fashion or otherwise become unavailable to users, data center  400 B can take over as the active data center. For example, domain name system (DNS) servers that associate a domain name of computational instance  322  with one or more Internet Protocol (IP) addresses of data center  400 A may re-associate the domain name with one or more IP addresses of data center  400 B. After this re-association completes (which may take less than one second or several seconds), users may access computational instance  322  by way of data center  400 B. 
       FIG.  4    also illustrates a possible configuration of managed network  300 . As noted above, proxy servers  312  and user  414  may access computational instance  322  through firewall  310 . Proxy servers  312  may also access configuration items  410 . In  FIG.  4   , configuration items  410  may refer to any or all of client devices  302 , server devices  304 , routers  306 , and virtual machines  308 , any applications or services executing thereon, as well as relationships between devices, applications, and services. Thus, the term “configuration items” may be shorthand for any physical or virtual device, or any application or service remotely discoverable or managed by computational instance  322 , or relationships between discovered devices, applications, and services. Configuration items may be represented in a configuration management database (CMDB) of computational instance  322 . 
     As noted above, VPN gateway  412  may provide a dedicated VPN to VPN gateway  402 A. Such a VPN may be helpful when there is a significant amount of traffic between managed network  300  and computational instance  322 , or security policies otherwise suggest or require use of a VPN between these sites. In some embodiments, any device in managed network  300  and/or computational instance  322  that directly communicates via the VPN is assigned a public IP address. Other devices in managed network  300  and/or computational instance  322  may be assigned private IP addresses (e.g., IP addresses selected from the 10.0.0.0-10.255.255.255 or 192.168.0.0-192.168.255.255 ranges, represented in shorthand as subnets 10.0.0.0/8 and 192.168.0.0/16, respectively). 
     IV. Example Device, Application, and Service Discovery 
     In order for remote network management platform  320  to administer the devices, applications, and services of managed network  300 , remote network management platform  320  may first determine what devices are present in managed network  300 , the configurations and operational statuses of these devices, and the applications and services provided by the devices, and well as the relationships between discovered devices, applications, and services. As noted above, each device, application, service, and relationship may be referred to as a configuration item. The process of defining configuration items within managed network  300  is referred to as discovery, and may be facilitated at least in part by proxy servers  312 . 
     For purpose of the embodiments herein, an “application” may refer to one or more processes, threads, programs, client modules, server modules, or any other software that executes on a device or group of devices. A “service” may refer to a high-level capability provided by multiple applications executing on one or more devices working in conjunction with one another. For example, a high-level web service may involve multiple web application server threads executing on one device and accessing information from a database application that executes on another device. 
       FIG.  5 A  provides a logical depiction of how configuration items can be discovered, as well as how information related to discovered configuration items can be stored. For sake of simplicity, remote network management platform  320 , third-party networks  340 , and Internet  350  are not shown. 
     In  FIG.  5 A , CMDB  500  and task list  502  are stored within computational instance  322 . Computational instance  322  may transmit discovery commands to proxy servers  312 . In response, proxy servers  312  may transmit probes to various devices, applications, and services in managed network  300 . These devices, applications, and services may transmit responses to proxy servers  312 , and proxy servers  312  may then provide information regarding discovered configuration items to CMDB  500  for storage therein. Configuration items stored in CMDB  500  represent the environment of managed network  300 . 
     Task list  502  represents a list of activities that proxy servers  312  are to perform on behalf of computational instance  322 . As discovery takes place, task list  502  is populated. Proxy servers  312  repeatedly query task list  502 , obtain the next task therein, and perform this task until task list  502  is empty or another stopping condition has been reached. 
     To facilitate discovery, proxy servers  312  may be configured with information regarding one or more subnets in managed network  300  that are reachable by way of proxy servers  312 . For instance, proxy servers  312  may be given the IP address range 192.168.0/24 as a subnet. Then, computational instance  322  may store this information in CMDB  500  and place tasks in task list  502  for discovery of devices at each of these addresses. 
       FIG.  5 A  also depicts devices, applications, and services in managed network  300  as configuration items  504 ,  506 ,  508 ,  510 , and  512 . As noted above, these configuration items represent a set of physical and/or virtual devices (e.g., client devices, server devices, routers, or virtual machines), applications executing thereon (e.g., web servers, email servers, databases, or storage arrays), relationships therebetween, as well as services that involve multiple individual configuration items. 
     Placing the tasks in task list  502  may trigger or otherwise cause proxy servers  312  to begin discovery. Alternatively or additionally, discovery may be manually triggered or automatically triggered based on triggering events (e.g., discovery may automatically begin once per day at a particular time). 
     In general, discovery may proceed in four logical phases: scanning, classification, identification, and exploration. Each phase of discovery involves various types of probe messages being transmitted by proxy servers  312  to one or more devices in managed network  300 . The responses to these probes may be received and processed by proxy servers  312 , and representations thereof may be transmitted to CMDB  500 . Thus, each phase can result in more configuration items being discovered and stored in CMDB  500 . 
     In the scanning phase, proxy servers  312  may probe each IP address in the specified range of IP addresses for open Transmission Control Protocol (TCP) and/or User Datagram Protocol (UDP) ports to determine the general type of device. The presence of such open ports at an IP address may indicate that a particular application is operating on the device that is assigned the IP address, which in turn may identify the operating system used by the device. For example, if TCP port 135 is open, then the device is likely executing a WINDOWS® operating system. Similarly, if TCP port 22 is open, then the device is likely executing a UNIX® operating system, such as LINUX®. If UDP port 161 is open, then the device may be able to be further identified through the Simple Network Management Protocol (SNMP). Other possibilities exist. Once the presence of a device at a particular IP address and its open ports have been discovered, these configuration items are saved in CMDB  500 . 
     In the classification phase, proxy servers  312  may further probe each discovered device to determine the version of its operating system. The probes used for a particular device are based on information gathered about the devices during the scanning phase. For example, if a device is found with TCP port 22 open, a set of UNIX®-specific probes may be used. Likewise, if a device is found with TCP port 135 open, a set of WINDOWS®-specific probes may be used. For either case, an appropriate set of tasks may be placed in task list  502  for proxy servers  312  to carry out. These tasks may result in proxy servers  312  logging on, or otherwise accessing information from the particular device. For instance, if TCP port 22 is open, proxy servers  312  may be instructed to initiate a Secure Shell (SSH) connection to the particular device and obtain information about the operating system thereon from particular locations in the file system. Based on this information, the operating system may be determined. As an example, a UNIX® device with TCP port 22 open may be classified as AIX®, HPUX, LINUX®, MACOS®, or SOLARIS®. This classification information may be stored as one or more configuration items in CMDB  500 . 
     In the identification phase, proxy servers  312  may determine specific details about a classified device. The probes used during this phase may be based on information gathered about the particular devices during the classification phase. For example, if a device was classified as LINUX®, a set of LINUX®-specific probes may be used. Likewise if a device was classified as WINDOWS® 2012, as a set of WINDOWS®-2012-specific probes may be used. As was the case for the classification phase, an appropriate set of tasks may be placed in task list  502  for proxy servers  312  to carry out. These tasks may result in proxy servers  312  reading information from the particular device, such as basic input/output system (BIOS) information, serial numbers, network interface information, media access control address(es) assigned to these network interface(s), IP address(es) used by the particular device and so on. This identification information may be stored as one or more configuration items in CMDB  500 . 
     In the exploration phase, proxy servers  312  may determine further details about the operational state of a classified device. The probes used during this phase may be based on information gathered about the particular devices during the classification phase and/or the identification phase. Again, an appropriate set of tasks may be placed in task list  502  for proxy servers  312  to carry out. These tasks may result in proxy servers  312  reading additional information from the particular device, such as processor information, memory information, lists of running processes (applications), and so on. Once more, the discovered information may be stored as one or more configuration items in CMDB  500 . 
     Running discovery on a network device, such as a router, may utilize SNMP. Instead of or in addition to determining a list of running processes or other application-related information, discovery may determine additional subnets known to the router and the operational state of the router&#39;s network interfaces (e.g., active, inactive, queue length, number of packets dropped, etc.). The IP addresses of the additional subnets may be candidates for further discovery procedures. Thus, discovery may progress iteratively or recursively. 
     Once discovery completes, a snapshot representation of each discovered device, application, and service is available in CMDB  500 . For example, after discovery, operating system version, hardware configuration and network configuration details for client devices, server devices, and routers in managed network  300 , as well as applications executing thereon, may be stored. This collected information may be presented to a user in various ways to allow the user to view the hardware composition and operational status of devices, as well as the characteristics of services that span multiple devices and applications. 
     Furthermore, CMDB  500  may include entries regarding dependencies and relationships between configuration items. More specifically, an application that is executing on a particular server device, as well as the services that rely on this application, may be represented as such in CMDB  500 . For instance, suppose that a database application is executing on a server device, and that this database application is used by a new employee onboarding service as well as a payroll service. Thus, if the server device is taken out of operation for maintenance, it is clear that the employee onboarding service and payroll service will be impacted. Likewise, the dependencies and relationships between configuration items may be able to represent the services impacted when a particular router fails. 
     In general, dependencies and relationships between configuration items may be displayed on a web-based interface and represented in a hierarchical fashion. Thus, adding, changing, or removing such dependencies and relationships may be accomplished by way of this interface. 
     Furthermore, users from managed network  300  may develop workflows that allow certain coordinated activities to take place across multiple discovered devices. For instance, an IT workflow might allow the user to change the common administrator password to all discovered LINUX® devices in single operation. 
     In order for discovery to take place in the manner described above, proxy servers  312 , CMDB  500 , and/or one or more credential stores may be configured with credentials for one or more of the devices to be discovered. Credentials may include any type of information needed in order to access the devices. These may include userid/password pairs, certificates, and so on. In some embodiments, these credentials may be stored in encrypted fields of CMDB  500 . Proxy servers  312  may contain the decryption key for the credentials so that proxy servers  312  can use these credentials to log on to or otherwise access devices being discovered. 
     The discovery process is depicted as a flow chart in  FIG.  5 B . At block  520 , the task list in the computational instance is populated, for instance, with a range of IP addresses. At block  522 , the scanning phase takes place. Thus, the proxy servers probe the IP addresses for devices using these IP addresses, and attempt to determine the operating systems that are executing on these devices. At block  524 , the classification phase takes place. The proxy servers attempt to determine the operating system version of the discovered devices. At block  526 , the identification phase takes place. The proxy servers attempt to determine the hardware and/or software configuration of the discovered devices. At block  528 , the exploration phase takes place. The proxy servers attempt to determine the operational state and applications executing on the discovered devices. At block  530 , further editing of the configuration items representing the discovered devices and applications may take place. This editing may be automated and/or manual in nature. 
     The blocks represented in  FIG.  5 B  are for purpose of example. Discovery may be a highly configurable procedure that can have more or fewer phases, and the operations of each phase may vary. In some cases, one or more phases may be customized, or may otherwise deviate from the exemplary descriptions above. 
     V. CMDB Identification Rules and Reconciliation 
     A CMDB, such as CMDB  500 , provides a repository of configuration items, and when properly provisioned, can take on a key role in higher-layer applications deployed within or involving a computational instance. These applications may relate to enterprise IT service management, operations management, asset management, configuration management, compliance, and so on. 
     For example, an IT service management application may use information in the CMDB to determine applications and services that may be impacted by a component (e.g., a server device) that has malfunctioned, crashed, or is heavily loaded. Likewise, an asset management application may use information in the CMDB to determine which hardware and/or software components are being used to support particular enterprise applications. As a consequence of the importance of the CMDB, it is desirable for the information stored therein to be accurate, consistent, and up to date. 
     A CMDB may be populated in various ways. As discussed above, a discovery procedure may automatically store information related to configuration items in the CMDB. However, a CMDB can also be populated, as a whole or in part, by manual entry, configuration files, and third-party data sources. Given that multiple data sources may be able to update the CMDB at any time, it is possible that one data source may overwrite entries of another data source. Also, two data sources may each create slightly different entries for the same configuration item, resulting in a CMDB containing duplicate data. When either of these occurrences takes place, they can cause the health and utility of the CMDB to be reduced. 
     In order to mitigate this situation, these data sources might not write configuration items directly to the CMDB. Instead, they may write to an identification and reconciliation application programming interface (API). This API may use a set of configurable identification rules that can be used to uniquely identify configuration items and determine whether and how they are written to the CMDB. 
     In general, an identification rule specifies a set of configuration item attributes that can be used for this unique identification. Identification rules may also have priorities so that rules with higher priorities are considered before rules with lower priorities. Additionally, a rule may be independent, in that the rule identifies configuration items independently of other configuration items. Alternatively, the rule may be dependent, in that the rule first uses a metadata rule to identify a dependent configuration item. 
     Metadata rules describe which other configuration items are contained within a particular configuration item, or the host on which a particular configuration item is deployed. For example, a network directory service configuration item may contain a domain controller configuration item, while a web server application configuration item may be hosted on a server device configuration item. 
     A goal of each identification rule is to use a combination of attributes that can unambiguously distinguish a configuration item from all other configuration items, and is expected not to change during the lifetime of the configuration item. Some possible attributes for an example server device may include serial number, location, operating system, operating system version, memory capacity, and so on. If a rule specifies attributes that do not uniquely identify the configuration item, then multiple components may be represented as the same configuration item in the CMDB. Also, if a rule specifies attributes that change for a particular configuration item, duplicate configuration items may be created. 
     Thus, when a data source provides information regarding a configuration item to the identification and reconciliation API, the API may attempt to match the information with one or more rules. If a match is found, the configuration item is written to the CMDB. If a match is not found, the configuration item may be held for further analysis. 
     Configuration item reconciliation procedures may be used to ensure that only authoritative data sources are allowed to overwrite configuration item data in the CMDB. This reconciliation may also be rules-based. For instance, a reconciliation rule may specify that a particular data source is authoritative for a particular configuration item type and set of attributes. Then, the identification and reconciliation API will only permit this authoritative data source to write to the particular configuration item, and writes from unauthorized data sources may be prevented. Thus, the authorized data source becomes the single source of truth regarding the particular configuration item. In some cases, an unauthorized data source may be allowed to write to a configuration item if it is creating the configuration item or the attributes to which it is writing are empty. 
     Additionally, multiple data sources may be authoritative for the same configuration item or attributes thereof. To avoid ambiguities, these data sources may be assigned precedences that are taken into account during the writing of configuration items. For example, a secondary authorized data source may be able to write to a configuration item&#39;s attribute until a primary authorized data source writes to this attribute. Afterward, further writes to the attribute by the secondary authorized data source may be prevented. 
     In some cases, duplicate configuration items may be automatically detected by reconciliation procedures or in another fashion. These configuration items may be flagged for manual de-duplication. 
     VI. Example Discovery of a Software Bus Application 
     Discovery patterns define various operations, processes, and rules that may be used to discover computing devices, software application, databases, and other entities within a managed network. The discovery patterns may also discover the relationships between these entities. In the case of software applications, for example, a particular discovery pattern may be tailored to a corresponding software application to account for the manner in which information needed for discovery of that software application is stored and made accessible. Accordingly, discovering multiple different software applications, for example, ordinarily involves multiple different discovery patterns. 
     However, when a plurality of software applications is interconnected by a software bus application, the software bus application may already contain or be aware of the information (or at least a portion thereof) usable for discovery of each of these software applications. Similarly, when a plurality of databases is managed by a database manager, the database manager may contain information (or at least a portion thereof) usable for discovery of these databases. Accordingly, a discovery pattern for the software bus application may be configured to leverage the information stored by the software bus to simultaneously discover the software bus and the software application interconnected thereby. Similarly, a discovery pattern for the database manager may be configured to leverage the information stored by the database manager to simultaneously discover the database manager and the databases managed thereby. 
     Additionally, the discovery pattern for the software bus and the discovery pattern for the database manager may be used in combination to determine relationships between the software applications and the databases. When discovery patterns are used independently of one another, generation of configuration items using one discovery pattern does not depend on information gathered by another discovery pattern. However, this independent approach may sometimes omit discovery of certain relationships between configuration items. In the example at hand, this independent approach might not be able to identify the specific databases used by a particular software application interconnected by a software bus. 
     Specifically, because the databases and software applications communicate indirectly by way of the database manager and the software bus, the specific software application and/or database to or from which a network packet is addressed might not be identifiable based on analysis of network traffic alone. Namely, a portion of the routing of data may be internal to the software bus and/or database manager, and thus not observable by monitoring network traffic. However, the software bus and the database manager may track this information, allowing for network traffic to be mapped to specific applications and databases. Accordingly, the data gathered by one discovery pattern may be correlated with or mapped to data gathered by the other discovery pattern, thus allowing a discovery application to identify the databases used by a particular software application, and vice versa. 
       FIG.  6    illustrates an example arrangement of a software bus application within a managed network. Software bus application  600  may be disposed on a server device or other computing device within managed network  300 . Software bus application  600  may be referred to as a software bus, for short, or an enterprise service bus (ESB). Software bus application  600  may communicatively connect a plurality of different software applications  602 ,  604 ,  606 ,  608 ,  610 ,  612 ,  614 ,  616 ,  618 , and  620  (i.e., applications  602 - 620 ) within managed network  300 . Applications  602 - 620  may be installed and configured to execute on one or more different computing devices within managed network  300 . 
     Applications  602 - 620  may communicate using different combinations of messaging formats, communication protocols, and other standards, as indicated by the patterns of the respective lines connecting applications  602 - 620  to software bus application  600 . Software bus protocol key  630  shows the format, protocol, or standard corresponding to each line pattern. Namely, applications  602 ,  604 , and  606  are configured to communicate according to a representational state transfer (REST) standard. Applications  608  and  610  are configured to communicate according to a raw native interface (RNI) standard. Applications  612  and  614  are configured to communicate according to a simple object access protocol (SOAP). Finally, applications  616 ,  618 , and  620  are configured to communicate according to a JAVA® native interface (JNI) standard. Applications may also be configured to communicate according to other formats, protocols, or standards not mentioned herein. 
     Software bus application  600  may, among other functions, facilitate communication and integration among applications that utilize different communication formats, protocols, or standards. For example, software bus application  600  may translate messages provided by application  602  into a format that application  620  is configured to interpret, parse, or otherwise understand. In general, software bus application  600  may be configured to route messages between applications  602 - 620  and to translate messages between the different formats, protocols, or standards shown in key  630 , for example. Accordingly, the communication formats, protocols, and standards of each of applications  602 - 620  may be modified without also having to modify the remaining applications to take into account this change. Instead, this change may be accounted for by software bus application  600 . 
     Software bus application  600  may provide a plurality of network ports for software applications  602 - 620  to use when connecting to software bus application  600 . In one example, each of the plurality of ports may be associated with a corresponding message format, protocol, and/or other standards. Thus, for example, in order to communicate by way of software bus application  600 , software application  610  is configured to address its communications to a network port assigned to the RNI standard. Each of applications  602 - 620  may be preconfigured with a list of the network ports on which software bus application  600  listens and the format, protocol, or standard associated with each port. Accordingly, software bus application  600  may determine the format, protocol, and/or standard used by a particular software application based on the port number to which the particular software application addresses its message. Alternatively, software bus application  600  may provide a plurality of universal network ports that can be used regardless of the format, protocol, or standard of a given software application. Each transmission may instead be decoded by software bus application  600  based on the contents thereof. 
     Notably, software bus application  600  may store (e.g., in a file) data that identifies each of software applications  602 - 620  and the attributes and parameters associated therewith. For example, this data may identify the services offered by a given software application and the communication format, protocol, and/or standard used thereby. The data may be generated and/or updated as each software application is first configured (e.g., by way of an initialization or setup procedure) to communicate by way of software bus application  600 . The data for a given software application may be updated as the given software application communicates by way of software bus application  600 . For example, when the given software application uses a network port assigned to a different communication format or protocol than it used previously, the data may be updated to reflect this change. Software bus application  600  may use this data to facilitate the communications between applications  602 - 620 . Additionally, this data may be usable by the discovery pattern to discover applications  602 - 620  by way of software bus application  600  as part of one discovery process. 
     Software bus application  600  may be connected to database system  622 , which may provide persistent data storage for one or more of applications  602 - 620 . Notably, database system  622  may represent one or more databases managed by a shared database manager. Applications  602 - 620  may access database system  622  by way of software bus application  600 . That is, in order to communicate with database system  622 , the data sent by each of applications  602 - 620  may first be transmitted to software bus application  600 . Software bus application  600  may then forward this data on to databases system  622 , reformatting the data as needed according to the message format, communication protocol, and/or other standards utilized by database system  622 . However, in some cases applications  602 - 620  may also be able to access database system  622  directly. Notably,  FIG.  8    illustrates an example architecture of database system  622 , which will be discussed in more detail below. 
     Software bus application  600  may provide additional functionality such as, for example, message queuing, exception or error handling, and enforcement of quality of communication service, among other possibilities. One example of software bus application  600  is RED HAT® JBOSS® Fuse which provides a platform for integration of software applications, services, and microservices (e.g., containerized software applications). Software bus application  600 , applications  602 - 620 , database system  622 , and the connections therebetween may be discovered and mapped by way of a discovery application. The discovery application may implement discovery patterns adapted for each of the configuration items sought to be discovered. For example, the discovery application may implement a discovery pattern configured to (i) identify that a software bus application is JBOSS® Fuse and (ii) execute a discovery procedure specific to JBOSS® Fuse to discover the structure, attributes, and parameters specific thereto. 
       FIG.  7    illustrates an example message flow diagram that details the discovery process of software bus application  600  and software applications  602 - 620 . Discovery of software bus application  600  and software applications  602 - 620  may be facilitated by discovery application  702 . Discovery application  702  may be disposed within remote network management platform  320  (e.g., within computational instance  322 ) or within managed network  300  (e.g., on proxy servers  312 ). However, in some implementations, aspects of discovery application  702  may also be distributed between remote network management platform  320 , managed network  300 , and/or other computing devices. 
     Configuration management database (CMDB)  704  may be configured to store configuration items representing any entities discovered in, for example, managed network  300 . Like discovery application  702 , CMDB  704  may be disposed within remote network management platform  320 , within managed network  300 , or distributed therebetween. Software bus application  600  may be hosted or disposed on server device  700  which, in turn, may form part of managed network  300 . 
     Discovery of software bus application  600  may be initiated by discovery application  702  obtaining or receiving access credentials for server  700 , as indicated by block  706 . The credentials may be, for example, secure socket shell (SSH) credentials that discovery application  702  may use to remotely access server device  700  by way of an SSH connection. In response to or based on obtaining the credentials at block  706 , discovery application  702  may transmit, to server device  700 , a request to establish a connection therewith using the credentials obtained at block  706 , as indicated by arrow  707 . Server  700  may validate the credentials and, if valid credentials were provided, establish the requested connection. Server device  700  may be configured to confirm establishment of the connection by transmitting, to discovery application  702 , and acknowledgement (ACK) of the established connection, as indicated by arrow  708 . 
     In response to or based on establishing the connection, discovery application  702  may be configured to probe server device  700  according to one or more discovery patterns to identify software bus application  600 , as indicated by arrow  709 . The probing may involve, for example, transmitting, to server device  700 , instructions configured to cause an operating system of server device  700  to identify software processes executing on server device  700  and/or scan various directories or files of server device  700  according to predetermined criteria. For example, discovery application  702  may initially detect software bus application  600  on server device  700  by searching a list of processes executing on server device  700  for processes whose names or parameters (e.g., working directory, command used to invoke the process, etc.) match those defined by the one or more discovery patterns. In another example, discovery application  702  may detect or gather additional information about software bus application  600  by scanning for directories or files whose names match or are similar to names defined within the one or more discovery patterns (e.g., directories whose names include “jboss” or “fuse,” in the case of JBOSS® Fuse). In response to or based on the probes, server device  700  may be configured to transmit, to discover application  702 , corresponding responses to the probes, as indicated by arrow  710 . 
     Based on or in response to such probing, discovery application may be configured to select one or more files to access within directories associated with software bus application  600 , as indicated by block  712 . The files and the directories may be selected based on one or more discovery patterns specific to software bus application  600 , which define operations, rules, and patterns for discovering software bus application  600  (rather than other applications). Notably, different discovery patterns may be used to discover software bus application  600  depending on the provider (e.g., RED HAT® vs ORACLE®), name (JBOSS® Fuse vs MULESOFT® ESB), or version (e.g., release version 1.5 vs release version 2.0) of software bus application  600  being discovered. 
     The one or more directories may be selected, for example, from a list of directories discovered on server device  700  by the probes at arrow  709 . In another example, the one or more directories may be selected bases on one or more software processes executing on sever device  700 . Namely, the probes at arrow  709  may be configured to cause server device  700  to identify one or more software processes executing thereon and corresponding to software bus application  600 . Each respective software process may be associated with corresponding attributes, which server device  700  may similarly be caused to identify. For example, the attributes for a respective software process may include a process identifier, a command used to invoke execution of the respective software process, a working directory associated with the respective software process, and/or files opened by the respective software process (along with their respective file system paths), among other possibilities. Discovery application  702  may be configured to select the one or more directories based on these attributes. For example, the one or more directories may include (i) the working directory of the respective process and (ii) any directories containing files opened by the respective process. 
     Accordingly, in one example, the one or more directories may include a directory in which software bus application  600  is installed and thus stores a portion of its files (e.g., a parent directory of the working directory). The one or more directories may also include a configuration directory (e.g., within the install directory) in which software bus application  600  stores various configuration files or other descriptive files (e.g., README files) that contain information regarding installation, configuration, and operation of software bus application  600 . The one or more directories may further involve system directories (e.g., /etc on LINUX® devices) shared by multiple different software applications in which the operating system stores various definitions, attributes, and parameters associated with software bus application  600 . For example, the “/etc” directory may contain a “services” file that defines network port numbers (e.g., TCP or UDP) that various services or applications configured for execution on server device  700  use to listen for incoming network traffic. 
     The one or more files selected to be accessed may include any files that store or are expected to store information necessary for discovering software bus application  600  and its connections with applications both inside and outside of managed network  300 . For example, README or configuration files may provide information regarding the name of software bus application  600 , the provider or vendor of software bus application  600 , the release version of software bus application  600 , and/or any plug-ins or add-ons used by software bus application  600 , among other information. The “services” file in the “/etc” directory may allow discovery application  702  to determine network ports on which software bus application  600  listens for connections from applications  602 - 620 , database system  622 , and/or other entities with which software bus application  600  interacts. For example, the services file (or another similar file) may define network ports on which software bus application  600  listens for communications from applications  602 - 620  and, for each of these network ports, the corresponding format, protocol, or standard (e.g., from software bus protocol key  630 ) assigned thereto. 
     The one or more selected files may also identify software applications  602 - 620  that are configured to communicate by way of software bus application  600 . For example, the one or more files may define, for each of software applications  602 - 620 , the communication format, protocol, and/or standard used thereby as well as any other identifiers, parameters, or attributes associated therewith. Thus, by accessing the information in such files, software applications  602 - 620  may be discovered by way of software bus application  600 . Notably, software applications  602 - 620  may be discovered without employing a separate discovery pattern for each of software applications  602 - 620  (although such separate patterns may nevertheless be used to supplement the information discovered by way of software bus application  600 ). 
     The specific directories and files that contain information involved in discovery of software bus application  600  and applications  602 - 620  may vary between different implementations of software bus application  600 . Accordingly, different discovery patterns may be developed to specify what files to access and where these files are located for a given implementation of software bus application  600 . 
     In response to or based on selecting the files to access at block  712 , discovery application  702  may be configured to transmit, to server device  700 , a request to access the selected files, as indicated by arrow  714 . This request may indicate specific information to be retrieved from the one or more files (e.g., portions of the file indicative of a type, name, provider, or version of software bus application  600 ). In response to or based on the request at arrow  714 , server device  700  may be configured to access the selected files to determine attributes of software bus application  600 , as indicated by block  716 . Specifically, server device  700  may access the selected files and extract or collect therefrom attributes identified by the discovery pattern. Server device  700  may access the files directly, by opening and reading their contents, or indirectly, by using one or more application programming interfaces (APIs) provided by software bus application  600 , for example. Notably, in some implementations, a portion of the information useful in determining the attributes identified by the discovery pattern may be stored in other ways such as, for example, in one or more databases. Nevertheless, this information may be accessible by way of the APIs or other means provided by software bus application  600 . 
     In response to or based on accessing the selected files and gathering the attributes of software bus application  600 , server device  700  may be configured to transmit, to discovery application  702 , data identifying the plurality of attributes, as indicated by arrow  718 . As discussed above, the attributes may include a provider, name, or version of software bus application  600 , network ports used by software bus application  600  to listen for incoming connections, and/or identifiers of software applications  602 - 620 , among other possibilities. In response to or based on receiving the data at arrow  718 , discovery application  702  may be configured to transmit, to server device  700 , a request to identify communicative connections established between or among software applications  602 - 620  by way of software bus application  600 , as indicated by arrow  720 . 
     The content and/or format of the request at arrow  720  may be based on the plurality of attributes provided to discovery application  702  at arrow  718 . Discovery application  702  may request that server device  700  and/or software bus application  600  monitor and log any messages and/or network traffic exchanged between or among application  602 - 620  by way of software bus application  600 . In response to or based on the request at arrow  720 , server device and/or software bus application  600  may be configured to generate and store data representing communicative connections established between or among applications  602 - 620  by way of software bus application  600 , as indicated by block  722 . 
     Communication among applications  602 - 620  may involve at least two steps. In one example, application  602  may be communicating with application  618 . Application  602  first transmits to software bus application  600  a first request to initiate a communicative connection therewith (e.g., a TCP SYN packet). The first request may be addressed to an IP address (e.g., 192.0.0.1) associated with server device  700  and a network port number (e.g., TCP port 81) (i) associated with software bus application  600  and (ii) corresponding to the communication format, protocol, or standard used by application  602 . The first request may originate from an IP address (e.g., 192.0.0.2) associated with a computing device on which application  602  is disposed and a network port assigned to application  602  (e.g., 2041). Once accepted, the first request forms a first communication socket (i.e., 192.0.0.2:2041, 192.0.0.1:81), indicating the two endpoints, source and destination, respectively, of the connection. 
     Application  602  may use this socket to communicate with software bus application  600 , sending messages or packets containing instructions or data intended for application  618 . Software bus application  600  may be configured to (i) identify application  602  as the source of this communication and/or (ii) identify application  618  as the destination or intended recipient of this communication. Software bus application  600  may also be configured to modify the messages as needed in order to translate between the format, protocol, and/or standard utilized by application  602  to the format, protocol, and/or standard utilized by application  618 . 
     Notably, when each listening port of software bus application  600  is assigned for communicating with a corresponding application of applications  602 - 620 , the source of the communication may be identifiable without parsing the message received from the corresponding application. Additionally, in some implementations, application  602  may be aware that one of application  604 - 620  is configured to provide a service sought by application  602 , but might not be aware of the identify of this application. Thus, application  602  may specify the desired service while software bus application  600  may be configured to select the application (e.g.,  618 ) configured to provide this service and transmit an appropriately-translated message thereto. 
     After receiving and translating the message from application  602 , software bus application  600  may then transmit to software application  618  a second request to initiate a communicative connection therewith. The second request may be addressed to an IP address (e.g., 192.0.0.3) associated with a computing device on which application  618  is disposed and a network port number (e.g., TCP port 8081) associated with software application  618 . The second request may originate from the IP address (e.g., 192.0.0.1) associated with server device  700  and a network port assigned thereto (e.g., 4082). Once accepted, the second request forms a second communication socket (i.e., 192.0.0.1:4082, 192.0.0.3:8081). 
     Software bus application  600  may use this socket to send to application  618  the modified message originating from application  602 . Additionally, application  618  may use the second socket to send a response back to software bus application  600 . Software bus application  600  may modify this response as needed in view of the differences between the formats, protocols, and standards used by applications  602  and  618  and transmit the modified response to application  602  by way of the first socket. 
     Accordingly, the data (representing communicative connections between applications  602 - 620 ) generated by server device  700  and/or software bus application  600  may include, for example, the source application (e.g., application  602  identified by its alphanumeric name), format, protocol, and/or standard used by the source application, destination application (e.g., application  618  identified by its alphanumeric name), format, protocol, and/or standard used by the destination application, and transmission time (e.g., start and end times) of messages exchanged among applications  602 - 620  by way of software bus application  600 . The strength or intensity of a communicative relationship between two applications may be estimated by the number of messages exchanged therebetween over a unit of time (e.g., one minute, one hour, one day, etc.) and/or a size of such messages. In some cases, the attributes collected at block  716  may be used to instruct server device  700  and/or software bus application  600  to monitor and log particular types of messages (e.g., messages indicating initiation of a connection between two applications) or information. In some implementations, software bus application  600  may provide an API or similar mechanism that provides a way to control the type of information collected by software bus application  600  and a way to access the collected data. 
     Notably, although any one of applications  602 - 620  may be configured to communicate with any other one of applications  602 - 620  due to the translation provided by software bus application  600 , only some combinations of these applications may actually establish active communicative connections. Because communications among applications  602 - 620  are made by way of software bus application  600 , it may be difficult to discover communicative relationships among applications  602 - 620  without using software bus application  600 . When, for example, a first application requests a service by way of software bus application  600  without specifying a second application that will provide the service, the requested service may appear, from the perspective of the first application, to be provided by software bus application  600 . That is, the first application might not be able to determine the identity of the second application. 
     Thus, a discovery pattern that discovers each of software applications  602 - 620  independently, rather than through software bus application  600 , might not be able to determine which software applications actually communicate with one another. Discovering software applications  602 - 620  by using data and functionality provided by software bus application  600  thus allows for discovery of such communicative connections. Accordingly, the data generated at block  722  may disambiguate pairs of software applications that could potentially communicate from pairs of applications that have successfully communicated in the past. 
     Based on or in response to identifying the communicative connections at block  722 , server device  700  may be configured to transmit, to discovery application  702 , data identifying the communicative connections, as indicated by arrow  724 . Based on or in response to receiving the data at arrow  724 , discovery application  702  may be configured to generate a mapping representing the communicative connections, as indicated by block  726 . The mapping may include, for example, nodes representing software bus application  600  and each of applications  602 - 620 . The mapping may also include connections between theses nodes that represent the communicative connections. Accordingly, the mapping may be configured to be visually rendered to represent the arrangement and relationships among software bus application  600  and applications  602 - 620 . For example, each of applications  602 - 620  may be shown as connected to one or more other applications by a line having a corresponding color and/or pattern that makes the relationship visually discernable. 
     Additionally, the mapping may indicate the respective computing devices on which each of the software application and databases are disposed. For example, the mapping may indicate that software bus application  600  is hosted by server device  700  by, for example, indicating the node of software bus application  600  as a sub-node within a larger node representing server device  700 . Similarly, when one or more of software applications  602 - 620  are distributed among one or more additional server devices, this distribution may be illustrated in a similar manner. Further, the mapping may indicate one or more of the attributes received at arrow  718 , such as, for example, the name, version, and/or provider (e.g., collectively representing the type) of software bus application  600 . 
     Based on or in response to generating the mapping at block  726 , discovery application  702  may be configured to transmit, to CMDB  704 , a request to store the generated mapping in CMDB  704 , as indicated by arrow  728 . In response to or based on the request at arrow  728 , CMDB  704  may be configured to store the mapping as one or more configuration items, as indicated by block  730 . The stored configuration items may be retrieved by one or more client devices to generate a visual representation of software bus application  600  and its relationships with server device  700 , and applications  602 - 620 , among others. 
     Additionally, discovery application  702  may be configured to transmit, to server device  700 , a further request to identify additional communicative connections between software bus application  600  and database system  622 . This request may be generated and transmitted in response to or based on storing the mapping at block  730 , or in response to or based on receiving the data at arrow  718 , for example. 
     The content of the further request may be based on the plurality of attributes provided to discovery application  702  at arrow  718 . Namely, discovery application  702  may request that server device  700  and/or software bus application  600  monitor and log any network traffic exchanged between database system  622  and any of application  602 - 620  by way of software bus application  600 . In response to or based on the further request, server device  700  and/or software bus application  600  may be configured to generate and store data representing additional communicative connections between software bus application  600 , applications  602 - 620 , and database system  622 , among others. 
     Software applications  602 - 620  may communicate with database system  622  (by way of software bus application  600 ) in a manner similar to that described above with respect to communication between two different applications. Namely, in the case of application  604  communicating with database system  622  by way of software bus application  600 , a first communication socket may be established between application  604  and software bus application  600  in response to a request from application  604 . Application  604  may use this socket to transmit any data or instructions intended for database system  622  by way of software bus application  600 . A second communication socket may be established between software bus application  600  and database system  622  in response to a request from software bus application  600 . Software bus application  600  may use this socket to transmit, to database system  622 , the data or instructions originating from application  604 . Notably, software bus application  600  may modify the data and/or instructions according to any differences between the format, protocol, and/or standards used by application  604  and database system  622 . 
     Software bus application  600  may also use the second socket to receive, from database system  622 , any communications responsive to the data and/or instructions. Again, these responsive communications may be modified as needed in view of any differences between the format, protocol, and/or standards used by application  604  and database system  622  and transmitted by software bus application  600  to application  604  by way of the first socket. Thus, software application  604  may, for example, store data in one or more databases of database system  622 , regardless of the format, protocol, and/or standards used by the one or more databases. 
     The data logged by server device  700  and/or software bus application  600  may indicate the source application (e.g., application  604 ) and database system  622  as the destination of the communication. For example, the data may identify the source application based on the first socket or aspects thereof (e.g., a particular application might be assigned a specific listening port of software bus application  600 ) and database system  622  based on the second socket or aspects thereof (e.g., database system  622  may be associated with a particular IP address and one or more port numbers on which database system  622  listens for incoming connections). In order to generate such data, software bus application  600  may be configured to map network traffic received from a software application by way of the first socket to network traffic transmitted to database system  622  by way of the second socket. Thus, network traffic generated by software bus application  600  on behalf of the software application may be mapped back to or otherwise associated with the software application that originated the communication. Additionally, software bus application  600  and/or server device  700  may be configured to track the times at which network packets or messages are transmitted and/or received via the first and second sockets. The logged data may be accessible, for example, by way of an API, command-line interface, or similar mechanism provided by software bus application  600 . 
     The attributes collected at block  716  may be used by server device  700 , software bus application  600 , and/or discovery application  702  to filter the monitored network traffic. For example, network packets that do not originate from and/or are not addressed to software bus application  600 , applications  602 - 620 , and/or database system  622  might not be tracked or logged. Alternatively or additionally, only network packets associated with a subset of applications  602 - 620  might be tracked. The strength or intensity of a communicative relationship between an application and database system  622  (or one or more databases thereof) may be estimated by the number of network packets (e.g., of a particular type) exchanged therebetween over a unit of time (e.g., one minute, one hour, one day, etc.) and/or the size of these packets. 
     Notably, the IP address corresponding to the server device on which database system  622  is located and the port number assigned to database system  622  may be determined using separate discovery patterns, as will be discussed with respect to  FIGS.  8  and  9   . In some implementations, this information may be discovered concurrently, by executing both discovery patterns in parallel. Alternatively, aspects of database system  622  may be discovered at an earlier time, and may be stored in configuration items in a CMDB that discovery application  702  may access. In either case, discovery application  702  may provide the IP address and port number associated with database system  622  to server device  700 , thereby allowing server device  700  to identify the additional communicative connections by monitoring network traffic between database system  622  and software bus application  600 . 
     Based on or in response to identifying the additional communicative connections, server device  700  may be configured to transmit, to discovery application  702 , data identifying the additional communicative connections. Based on or in response to receiving the data, discovery application  702  may be configured to generate an additional mapping representing the additional communicative connections. The additional mapping may include, for example, a node representing database system  622  and connections between this node and the nodes determined at block  726 , thereby representing the additional communicative connections. Namely, the additional mapping may represent communicative connections between database system  622  and software applications  602 - 620 . 
     The additional mapping and the mapping determined at block  726  may be visually rendered to represent the arrangement and relationships among software bus application  600 , applications  602 - 620 , and database system  622 . In some cases, the additional mapping may be expressed as a modification to the mapping generated at block  726 , rather than as a separate mapping. 
     Based on or in response to generating the additional mapping, discovery application  702  may be configured to transmit, to CMDB  704 , a request to store the additional mapping in CMDB  704 . In response to or based on this request, CMDB  704  may be configured to store the additional mapping in one or more additional configuration items. The stored configuration items may be retrieved by one or more client devices to generate a visual representation of software bus application  600  and its relationships with server device  700 , applications  602 - 620 , and database system  622 , among others. 
     Notably, as will be described in more detail below, combining the discovery process shown in  FIG.  7    with a discovery process for database system  622 , as shown in and described with respect to  FIGS.  8  and  9   , may allow for generation of a further mapping that reflects how individual databases that make up database system  622  relate to software bus application  600  and applications  602 - 620 . 
     VII. Example Discovery of a Database Manager 
       FIG.  8    illustrates an example implementation of a database system such as, for example, IBM® INFORMIX®. The database system may represent, for example, database system  622  illustrated in and discussed with respect to  FIGS.  6  and  7   . The database system may include database manager  802  and a plurality of secondary databases  830 ,  840 ,  850 ,  860 ,  870 , and  880  (i.e., hereinafter referred to as databases  830 - 880 ). In one example, databases  830 - 880  may represent different physical databases that are represented as one logical database by database manager  802 . 
     Notably, databases  830 - 880  are herein referred to as “secondary” to distinguish them from CMDB  704  and CMDB  902 . Databases  830 - 880  may be used to store data on behalf of applications  602 - 620 , while CMDB  704  and CMDB  902  are used to store configuration items for managed network  300 . Additionally, databases  830 - 880  may form part of managed network  300  while CMDB  704  and CMDB  902  may be disposed in remote network management platform  320 . However, although secondary databases  830 - 880 , CMDB  704 , and CMDB  902  may store different types of data and may be part of different computing systems, each of these databases may be implemented using similar technologies, techniques, and/or standards (e.g., SQL). 
     Database manager  802  may be disposed on server device  800 , which, in turn, may form part of managed network  300 . In some implementations, however, database manager  802  may be disposed on server device  700  such that it is co-located with software bus application  600  (i.e., server device  800  and server device  700  may represent to the same computing device). Secondary databases  830 ,  840 ,  850 , and  860  may be disposed on server device  800 , while secondary databases  870  and  880  may be disposed on server devices  876  and  886 , respectively. The database system might thus be distributed among multiple computing devices. 
     The database system may be communicatively connected to software applications  816 ,  818 ,  820 , and  822  (i.e., applications  816 - 822 ). Applications  816 - 822  may access corresponding secondary databases  830 - 880  by way of database manager  802 . Database manager  802  may thus operate to manage interactions between software applications seeking to use secondary databases  830 - 880  of the database system. Notably, databases  830 - 880  may be accessible by way of one or more network ports on which database manager  802  listens for incoming connections. In some implementations, applications  816 - 820  may be connected to each other and/or to database manager  802  by way of a software bus application, as shown and discussed with respect to  FIG.  6   . Applications  816 - 822  may thus be analogous to applications  602 - 620 . 
     Database manager  802  may be associated with a plurality of attributes  804  that provide additional descriptive details regarding database manager  802 . Attributes  804  may be used to disambiguate database manager  802  from other database management systems. Attributes  804  may include, for example, an indication of version  806  of database manager  802  being executed on server device  800 , processes  808  associated with database manager  802  that are running on server device  800 , network ports  810  used by database manager  802 , install directory  812  in which database manager  802  is installed, and one or more configuration files  814  that define various parameters according to which database manager  802  is configured to operate, among other attributes. 
     Each of secondary databases  830 - 880  may contain therein data stored on behalf of one or more software applications (e.g., applications  816 ,  818 ,  820 , and  822 ) and may be associated with a corresponding database catalog. Namely, secondary database  830  contains data  834  and is associated with catalog  832 , secondary database  840  contains data  844  and is associated with catalog  842 , secondary database  850  contains data  854  and is associated with catalog  852 , secondary database  860  contains data  864  and is associated with catalog  862 , secondary database  870  contains data  874  and is associated with catalog  872 , and secondary database  880  contains data  884  and is associated with catalog  882 . Notably, the catalogs may be stored in their corresponding databases or as part of database manager  802  (e.g., a part of a master database thereof). 
     Each database catalog may contain metadata that defines or describes the components of the corresponding database and the attributes of those components. For example, catalog  842  may define the tables in database  840 , the rows and columns that make up database  840 , the relationships between the different tables within database  840 , the data types associated with the columns, the model utilized by database  840  to store data  844  (e.g., relational model or object-relational model), and database views (i.e., stored database queries that return a subset of the data, sometimes referred to as virtual tables), among other possibilities. Thus, a database catalog may define a structure of a corresponding database. The catalogs may also track database sessions and activity. For example, catalog  882  may indicate the times at which database  880  was accessed and the operations or transactions carried out at such times. Notably, as described in more detail below, the information stored in the catalogs may be combined with the communicative connections tracked by software bus application  600  and/or server device  700  to determine how databases  830 - 880  relate to applications  602 - 620 . 
       FIG.  9    illustrates an example message flow diagram that details the discovery process of the database system shown in  FIG.  8   , including database manager  802  and secondary databases  830 - 880 . The discovery process may be facilitated by discovery application  900 . In some cases, discovery application  900  may be the same as discovery application  702 , but may utilize a different discovery pattern to discover the database system. Alternatively, the two discovery applications may be different, each implementing a different discovery process specific to the configuration item sought to be discovered. Nevertheless, much like discovery application  702 , discovery application  900  may be disposed within remote network management platform  320 , disposed within managed network  300 , or distributed therebetween. 
     Similarly, CMDB  902  and CMDB  704  may refer to the same database. Alternatively, CMDB  902  and CMDB  704  may represent different databases each configured to store particular types of configuration items (e.g. configuration items representing applications vs configuration items representing databases). CMDB  902  may be disposed in remote network management platform  320 . However, in some implementations, CMDB  902  may alternatively be disposed in managed network  300  or distributed among managed network  300 , remote network management platform  320 , and/or other computing devices. Likewise, server device  800  and server device  700  may represent the same or different server device, depending on the implementation. 
     Discovery of database manager  802  may involve discovery application  900  determining a command configured to cause server device  800  to identify a type of database manager  802 , as indicated by block  904 . The type of database manager  802  may include or be defined by a name (e.g., INFORMIX®) of database manager  802 , a vendor or provider (e.g., IBM®) of database manager  802 , and/or a version (e.g., release 12.0) of database manager  802 , among other possibilities. Discovery application  900  may determine the command based on the results of one or more probes transmitted to server device  800 . As discussed with respect to  FIG.  7   , the probes may contain instructions to identify executing processes, scan various directories, and/or scan various files on server device  800 . Notably, however, in this case, the probes may be configured to scan for processes, directories, and files associated with various types of database managers, rather than software buses. Accordingly, in response to one or more probes detecting database manager  802 , the command may be selected to obtain additional information regarding database manager  802 . 
     Based on or in response to selecting the command at block  904 , discovery application  900  may be configured to transmit, to server device  800 , instructions to execute the command, as indicated by arrow  906 . As in the case of software bus application  600 , the instructions may be transmitted by way of an SSH connection established based on or in response to obtaining valid credentials for connecting to server device  800 . 
     Based on or in response to reception of the instructions at arrow  906 , server device  800  may be configured to execute the command, as indicated by block  908 . The command may involve instructions configured to cause server device  800  to access one or more files, obtain attributes of one or more executing processes, and/or query an API provided by database manager  802  to obtain data indicating the type of database manager  802 . In the case of the IBM® INFORMIX® database system, for example, the command “onstat-g dis” may be executed by server device  800  in an operating system command shell to determine the type of database manager  802  based on, for example, attributes  804  of database manager  802 . Notably, the specific process carried out by server device  800  may depend on the results of the probes transmitted to server device  800  and the discovery patterns used in an attempt to obtain the data indicating version  806 . 
     Based on or in response to executing the command at block  908 , server device  800  may be configured to transmit, to discovery application  900 , first data identifying the type of database manager  802 , as indicated by arrow  910 . Based on or in response to receiving the first data at arrow  910 , discovery application  900  may be configured to select one or more additional commands configured to cause database manager  802  to determine, for each of secondary databases  830 - 880 , a respective catalog, as indicated by block  912 . Discovery application  900  may be configured to select the one or more additional commands based on a discovery pattern corresponding to the type of database manager  802  as identified by the first data. That is, the one or more additional commands may be specific to the type (e.g., version, name, and/or provider) of database manager  802 . 
     Based on or in response to selecting the one or more additional commands at block  912 , discovery application  900  may be configured to transmit, to server device  800 , instructions to execute the one or more additional commands. Based on or in response to receiving the one or more additional commands at arrow  914 , database manager  802  may be configured to execute the one or more additional commands, thereby generating second data indicating the respective catalog for each of databases  830 - 880 . In the case of the IBM® INFORMIX® database system, for example, the second command may be “dbaccess sysmaster,” which may cause database manager  802  to access an internal “master” database in database manager  802  that contains the respective catalogs of databases  830 - 880 . In other cases, the one or more additional commands may cause database manager  802  to retrieve the respective catalogs stored in each of databases  830 - 880 . 
     Based on or in response to execution of the one or more additional commands at block  916 , server device  800  may be configured to transmit, to discovery application  900 , second data identifying database catalogs  832 ,  842 ,  852 ,  862 ,  872 , and  882 , as indicated by arrow  918 . In some implementations, the second data may identify the catalogs (i.e., indicate which catalogs exist) as well as represent the contents thereof. That is, the second data may identify databases  830 - 880  and indicate how each of these databases is structured or organized, what each database contains, and how/when each database has been accessed or updated. 
     Accordingly, each of databases  830 - 880  may thus be discovered using a single discovery process by leveraging database manager  802  and the information stored and/or accessible thereby. That is, discovery application  900  might not have to implement or execute a separate, independent discovery process for each of databases  830 - 880 , much like discovery application  702  might not have to implement a separate discovery process for each of applications  602 - 620 . 
     Based on or in response to receiving the second data at arrow  918 , discovery application  900  may be configured to generate a mapping between database manager  802  and the database catalogs, as indicated by block  920 . The mapping may thus indicate databases  830 - 880  that are managed by database manager  802 , as well as the structure of each of these databases. Based on or in response to generating the mapping at block  920 , discovery application  900  may be configured to transmit, to CMDB  902 , a request to store the mapping in CMDB  902  in one or more configuration items, as indicated by arrow  922 . Based on or in response to the request at arrow  922 , CMDB  902  may be configured to store therein the mapping in the one or more configuration items for later retrieval, as indicated by block  924 . 
     Thus, after discovery, the database system (i.e., database manager  802  and secondary databases  830 - 880 ) and the structure thereof may be visualized by computing devices within, for example, managed network  300  based on the stored configuration items. 
     With the structure of the database system represented in CMDB  902 , the relationships between the database system and other applications and devices within managed network  300  may be visualized as well. Namely, when the database system is utilized by one or more applications connected by way of a software bus application, as discussed with respect to  FIG.  7   , the database manager  802  may be mapped to software bus application  600 . The relationship between database manager  802  and software bus application  600  may be identified based on communicative connections detected therebetween (e.g., as discussed above with respect to  FIG.  7   ). 
     This mapping between software bus application  600  and database manager  802  may generally indicate that applications  602 - 620  may utilize databases  830 - 880 . Notably, as discussed above, the discovery pattern for software bus application  600  may discover that a particular software application communicates with database manager  802  by way of software bus application  600 . However, this discovery pattern, when used independently, might not be able to identify the specific secondary database used by the particular application. On the contrary, when the discovery patterns for each of software bus application  600  and database manager  802  are used in combination, the discovery application may determine how applications  602 - 620  utilize databases  830 - 880 . 
     Namely, the network traffic monitored by server device  700  and/or software bus application  600  may be combined with the information contained in database catalogs  832 ,  842 ,  852 ,  862 ,  872 , and  882  to identify the databases used by a particular application. The data representing the monitored network traffic may indicate, for each network packet, the times at which the network packet was transmitted or received at different points along the transmission path. For example, the data may indicate (i) a first time at which a particular network packet was received by software bus application  600  from a source software application (e.g., one of software applications  602 - 620 ) and/or (ii) a second time at which the particular network packet (which may be modified by software bus application  600 ) was transmitted from software bus application  600  to database manager  802 . Additionally, in implementations where network traffic is also monitored by server device  800  and/or database manager  802 , the data representing the monitored network traffic may also indicate (iii) a third time at which the particular network packet was received from software bus application  600  by database manager  802  and/or (iv) a fourth time at which a further network packet responsive to the communication from the source application was transmitted to software bus application  600 . Further, the data may indicate (v) a fifth time at which the further network packet was received by software bus application  600  from database manager  802  and/or (vi) a sixth time at which the further network packet (which may be modified by software bus application  600 ) was transmitted from software bus application  600  to the source software application. Other times may be tracked as well. 
     Similarly, the database catalog of a particular secondary database may indicate the times at which the particular secondary database was accessed or modified. Accordingly, the first through sixth times associated with the network packets may be correlated with a time of a corresponding transaction, as represented by the database catalog, with the particular secondary database. For example, a first network packet may be correlated with one or more database transactions occurring within a threshold time interval after the first, second, and/or third times and/or before the fourth, fifth, and/or sixth times. Since each network packet is associated with a particular software application (and this association is monitored by software bus application  600 ), as discussed with respect to  FIG.  7   , the particular software application may be mapped to the particular secondary database, indicating a communicative relationship therebetween. 
     In one example, secondary database  840  may be used by application  604  to store data. Application  604  may communicate with database  840  by way of software bus application  600  and database manager  802 . For example, application  604  may generate a request to store particular data in database  840 . Application  604  may establish a first communicative connection with software bus application  600 , forming a first socket, and may transmit the request to software bus application  600  in one or more network packets by way of the first socket. Software bus application  600  may log the time at which the one or more network packets are received thereby and the identity of software application  604  from which the network packets are received. Software bus application  600  may then modify the request and/or the one or more network packets according to any differences between the format, protocol, and/or standards used by application  604  and database manager  802 . 
     Software bus application  600  may establish a second communicative connection with database manager  802 , forming a second socket, and may transmit the modified request in one or more modified network packets to database manager  802  by way of the second socket. Software bus application  600  may log the time at which the one or more modified network packets are transmitted to database manager  802 . 
     In response to receiving the one or more modified network packets, database manager  802  may be configured to comply with the request contained therein and store the particular data in database  840  (provided sufficient storage space is available). The storage transaction of the particular data may be reflected in catalog  842 . Catalog  842  may also indicate the time at which the particular data was stored in database  840  (i.e., the transaction time). Thus, a communicative relationship may be identified between application  604  and database  840  based on (i) the times at which network packets are transmitted by software bus application  600  on behalf of software application  604  and (ii) the transaction times indicated by database catalog  842 . Notably, this communicative relationship may be identified even when communications between database manager  802  and database  840  are difficult to detect (e.g., the communications involve inter-process communication) or are undetectable (e.g., one process handles the described operations of the database system). 
     Database manager  802  may transmit, to software bus application  600  and by way of the second socket, confirmation of successful storage of the particular data. Similarly, software bus application  600  may modify this confirmation and transmit it to software application  604  by way of the first socket. The first and second sockets may be subsequently closed. 
     Application  604  may thus be mapped to database  840 . Notably, by combining (i) the traffic data monitored by software bus application  600  with (ii) the information stored in the catalogs associated with databases  830 - 880 , application  604  may be mapped to database  840  even though application  604  communicates with database  840  by way of software bus application  600  and database manager  802  (rather than communicating with database  840  directly). Thus, by using the information obtained by both discovery patterns in parallel or combination, applications  602 - 620 , which are “hidden” behind software bus application  600 , and secondary databases  830 - 880 , which are “hidden” behind database manager  802 , may be mapped to each other directly. On the contrary, using such patterns individually, without correlating network traffic monitored by software bus application  600  with database transactions indicated by database catalogs, might allow for mapping of software bus application  600  to database manager  802 , but might not unambiguously allow the databases used by a particular application to be identified. 
     VIII. Example Operations 
       FIGS.  10  and  11    are flow charts illustrating an example embodiment. The processes illustrated by  FIGS.  10  and  11    may be carried out by a computing device, such as computing device  100 , and/or a cluster of computing devices, such as server cluster  200 . However, the processes can be carried out by other types of devices or device subsystems. For example, the processes could be carried out by a portable computer, such as a laptop or a tablet device. 
     The embodiments of  FIGS.  10  and  11    may be simplified by the removal of any one or more of the features shown therein. Further, these embodiments may be combined with features, aspects, and/or implementations of any of the previous figures or otherwise described herein. 
     Turning now to  FIG.  10   , block  1000  involves obtaining, by a computing system associated with a remote network management platform that is associated with a managed network, credentials for remotely accessing a server device that (i) is disposed in the managed network and (ii) hosts a software bus application. The managed network includes a plurality of software applications communicatively connected by way of the software bus application. 
     Block  1002  involves selecting, by the computing system and based on a pattern corresponding to the software bus application, one or more files to access. 
     Block  1004  involves transmitting, by the computing system and to the server device, instructions to access the one or more files. 
     Block  1006  involves receiving, by the computing system and from the server device, data identifying a plurality of attributes of the software bus application determined by accessing the one or more files. 
     Block  1008  involves, based on the data identifying the plurality of attributes, transmitting, by the computing system and to the server device, instructions to identify communicative connections established between the plurality of software applications by way of the software bus application. 
     Block  1010  involves receiving, by the computing system and from the server device, data identifying the communicative connections. 
     Block  1012  involves, based on (i) the plurality of attributes and (ii) the communicative connections, generating, by the computing system, a mapping that represents the communicative connections. 
     Block  1014  involves storing, in a configuration management database disposed within the remote network management platform, the mapping in one or more configuration items. 
     In some embodiments, the instructions to identify the communicative connections established between the plurality of software applications may be configured to cause the software bus application to identify an active communicative connection between (i) a first software application of the plurality of software applications and (ii) a second software application of the plurality of software applications based on one or more messages exchanged between the first software application and the second software application by way of the software bus application. 
     In some embodiments, wherein a first subset of the plurality of software applications may be configured to communicate according to a first protocol and a second subset of the plurality of software applications may be configured to communicate according to a second protocol different from the first protocol. The software bus application may be configured to transmit messages between software applications of the first subset and software applications of the second subset by translating the messages between the first protocol and the second protocol. 
     In some embodiments, based on the data identifying the plurality of attributes, instructions to identify additional communicative connections between the software bus application and a database system used by at last one of (i) the software bus application or (ii) the plurality of software applications may be transmitted to the server device. Data identifying the additional communicative connections may be received from the server device. Based on (i) the plurality of attributes and (ii) the additional communicative connections, an additional mapping that represents the additional communicative connections may be generated. The additional mapping may be stored in one or more additional configuration items in the CMDB. 
     In some embodiments, the database system may include a database manager and a plurality of secondary databases managed by the database manager. The additional communicative connections may be established between one or more of the plurality of software applications and one or more corresponding databases of the secondary databases by way of the software bus application and the database manager. 
     In some embodiments, the instructions to identify the additional communicative connections between the software bus application and the database system may be configured to cause the server device to monitor network traffic between the database system and at least one of (i) the plurality of software applications or (ii) the software bus application. 
     In some embodiments, the plurality of attributes may include one or more network ports used by at least one of (i) the software bus application or (ii) the plurality of software applications to establish the communicative connections. 
     In some embodiments, the one or more files may include a configuration file that defines settings according to which the software bus application is configured to operate. 
     In some embodiments, the plurality of attributes may include a type of the software bus application. 
     In some embodiments, the plurality of attributes may include identifiers of each of the plurality of software applications communicatively connected by way of the software bus application. 
     In some embodiments, the mapping may represent a relationship between the software bus application and the server device. 
     In some embodiments, instructions to identify one or more directories that contain the one or more files may be transmitted to the server device. Data identifying the one or more directories may be received from the server device. 
     In some embodiments, the instructions to identify the one or more directories may be configured to (i) cause the server device to identify one or more executing processes corresponding to the software bus application and (ii) identify the one or more directories based on other attributes associated with the one or more executing processes. 
     Turning now to  FIG.  11   , block  1100  involves identifying, by a computing system, a type of a database manager hosted by a server device associated with a managed network. The database manager is configured to manage one or more secondary databases that are configured to store data for software applications executable by the managed network. Identifying the type of the database manager involves causing the server device to execute a command configured to cause the database manager to identifying the type thereof. 
     Block  1102  involves selecting, by the computing system and based on a pattern corresponding to the type of the database manager, one or more additional commands. 
     Block  1104  involves determining, by the computing system, respective database catalogs of the one or more secondary databases by (i) causing the server device to execute the one or more additional commands and (ii) receiving, from the server device, data identifying the respective database catalogs of the one or more secondary databases. Each database catalog identifies a structure of a corresponding secondary database of the one or more secondary databases. 
     Block  1106  involves generating, by the computing system and based on the received data, a mapping between the database manager and each of the respective database catalogs of the one or more secondary databases. 
     Block  1108  involves storing, in a configuration management database that is associated with the managed network and disposed within a computational instance of a remote network management platform, the generated mapping as one or more configuration items. 
     In some embodiments, based on a plurality of network connection parameters associated with the database manager, communicative connections between the software applications and the database manager may be identified. An additional mapping may be generated to indicate the communicative connections. 
     In some embodiments, the server device may be caused to identify a directory containing files associated with the database manager. Based on the pattern corresponding to the type of the database manager, one or more files may be selected to access within the directory to determine the plurality of network connection parameters associated with the database manager. Instructions to access the one or more files may be transmitted to the server device. Additional data identifying the plurality of network connection parameters may be received from the server device. 
     In some embodiments, the software applications may be communicatively connected by way of a software bus application. The additional mapping may indicate that the communicative connections between the software applications and the database manager are by way of the software bus application. 
     In some embodiments, the additional mapping may indicate, for each software application of the software applications, a corresponding communicative connection with a respective secondary database of the one or more secondary databases. 
     In some embodiments, the type of the database manager may indicate a provider of the database manager. 
     In some embodiments, the type of the database manager may indicate a name of the database manager. 
     In some embodiments, the type of the database manager may indicate a release version of the database manager. 
     In some embodiments, the respective database catalog of a particular database of the one or more secondary databases may include metadata identifying respective times of transactions between the particular database and one or more of the software applications. 
     In some embodiments, the respective database catalog of a particular database of the one or more secondary databases may include metadata identifying (i) tables that make up the particular database, (ii) columns that make of the tables, and (iii) data types stored in each of the columns. 
     In some embodiments, the command may include at least one of (i) instructions configured to cause the server device to identify parameters of one or more software processes associated with the database manager, (ii) instructions configured to cause the server device to access one or more files associated with the database manager, or (iii) instructions configured to cause the server device to invoke execution of one or more operations of an application programming interface provided by the database manager. 
     In some embodiments, a first database catalog of a particular database of the one or more secondary databases may indicate that the particular database is configured to store data according to a relational database model. A second database catalog of another database of the one or more secondary databases may indicate that the another database is configured to store data according to an object-relational database model. The mapping may indicate a respective database model for each of the one or more secondary databases. 
     In some embodiments, a communicative connection may be established with the server device based on access credentials. In response to establishing the communicative connection with the server device, the server device may be probed for software products configured to execute thereon. Based on the software products identified by the probes, the command may be determined. 
     IX. Conclusion 
     The present disclosure is not to be limited in terms of the particular embodiments described in this application, which are intended as illustrations of various aspects. Many modifications and variations can be made without departing from its scope, as will be apparent to those skilled in the art. Functionally equivalent methods and apparatuses within the scope of the disclosure, in addition to those described herein, will be apparent to those skilled in the art from the foregoing descriptions. Such modifications and variations are intended to fall within the scope of the appended claims. 
     The above detailed description describes various features and operations of the disclosed systems, devices, and methods with reference to the accompanying figures. The example embodiments described herein and in the figures are not meant to be limiting. Other embodiments can be utilized, and other changes can be made, without departing from the scope of the subject matter presented herein. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations. 
     With respect to any or all of the message flow diagrams, scenarios, and flow charts in the figures and as discussed herein, each step, block, and/or communication can represent a processing of information and/or a transmission of information in accordance with example embodiments. Alternative embodiments are included within the scope of these example embodiments. In these alternative embodiments, for example, operations described as steps, blocks, transmissions, communications, requests, responses, and/or messages can be executed out of order from that shown or discussed, including substantially concurrently or in reverse order, depending on the functionality involved. Further, more or fewer blocks and/or operations can be used with any of the message flow diagrams, scenarios, and flow charts discussed herein, and these message flow diagrams, scenarios, and flow charts can be combined with one another, in part or in whole. 
     A step or block that represents a processing of information can correspond to circuitry that can be configured to perform the specific logical functions of a herein-described method or technique. Alternatively or additionally, a step or block that represents a processing of information can correspond to a module, a segment, or a portion of program code (including related data). The program code can include one or more instructions executable by a processor for implementing specific logical operations or actions in the method or technique. The program code and/or related data can be stored on any type of computer readable medium such as a storage device including RAM, a disk drive, a solid state drive, or another storage medium. 
     The computer readable medium can also include non-transitory computer readable media such as computer readable media that store data for short periods of time like register memory and processor cache. The computer readable media can further include non-transitory computer readable media that store program code and/or data for longer periods of time. Thus, the computer readable media may include secondary or persistent long term storage, like ROM, optical or magnetic disks, solid state drives, compact-disc read only memory (CD-ROM), for example. The computer readable media can also be any other volatile or non-volatile storage systems. A computer readable medium can be considered a computer readable storage medium, for example, or a tangible storage device. 
     Moreover, a step or block that represents one or more information transmissions can correspond to information transmissions between software and/or hardware modules in the same physical device. However, other information transmissions can be between software modules and/or hardware modules in different physical devices. 
     The particular arrangements shown in the figures should not be viewed as limiting. It should be understood that other embodiments can include more or less of each element shown in a given figure. Further, some of the illustrated elements can be combined or omitted. Yet further, an example embodiment can include elements that are not illustrated in the figures. 
     While various aspects and embodiments have been disclosed herein, other aspects and embodiments will be apparent to those skilled in the art. The various aspects and embodiments disclosed herein are for purpose of illustration and are not intended to be limiting, with the true scope being indicated by the following claims.