Patent Publication Number: US-10331460-B2

Title: Upgrading customized configuration files

Description:
RELATED APPLICATION 
     Benefit is claimed under 35 U.S.C. 119(a)-(d) to Foreign Application Serial No. 201641033264 filed in India entitled “UPGRADING CUSTOMIZED CONFIGURATION FILES”, filed on Sep. 29, 2016, by VMware, Inc., which is herein incorporated in its entirety by reference for all purposes. 
     BACKGROUND 
     Software products typically include configuration files. Configuration files can be used with applications, services, processes and operating systems, among others. The configuration file can define the behavior of the application, service, process, operating system, etc. Some configuration files are used at startup while others are read periodically to check for changes. 
     A configuration file includes configuration property values that define various parameters and initial settings. Examples of configuration file properties include IP address of an endpoint, a number of threads to be started for a service, a number of connections allowed for a particular database, etc. Some applications provide tools to create or customize the configuration property values of a configuration file (e.g., via a graphical user interface or text editor). 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a flow chart illustrating a method of upgrading a customized configuration file according to a number of embodiments of the present disclosure. 
         FIG. 2  is a block diagram of a truth table for a three-way merge algorithm according to a number of embodiments of the present disclosure. 
         FIG. 3  is a block diagram of a system for upgrading a customized configuration file according to a number of embodiments of the present disclosure. 
         FIG. 4  is a diagram of a system for upgrading a customized configuration file according to a number of embodiments of the present disclosure. 
         FIG. 5  is a diagram of a machine for upgrading a customized configuration file according to a number of embodiments of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     In many instances, some of the configuration property values in a configuration file are customized by a user or administrator based on their computing environment. For example, a configuration property comprising an IP address for a particular endpoint may be customized with a particular configuration property value (e.g., a specific IP address). When a configuration property value is customized, the configuration file may be referred to as a customized configuration file. The previous version configuration file (in some instances, an original configuration file) can be customized with different configuration property values than were included in the previous version configuration file. 
     The previous version configuration file may include default configuration property values. In some instances, a particular configuration property value may be empty (null) in the previous version configuration file. In either case, the configuration property value may be customized (either added or changed) to suit the needs of a particular computing environment. 
     Configuration files as a whole may be upgraded either independently or as part of an upgrade to the software underlying the configuration file (e.g., application, service, process, operating system, etc.). For example, the upgrade can be a release of a new version of the software. However, if the upgraded configuration file replaces a customized configuration file, the customized configuration property values may be lost or replaced. This can have the undesirable side effect of forcing the user or administrator to have to manually change the configuration property values back to their preferred customized values. 
     Some previous approaches to retaining such custom configuration settings may apply a two-way merge mechanism. However, such approaches cannot automatically merge customized configuration property values correctly when the default value changes during multiple releases of the configuration file. With a two-way merge, there is no way to detect whether the configuration property value changes as part of a newer version of the configuration file or as a result of it being customized in a previous version configuration file. In such instances, the configuration file, or the application underlying the configuration file, would have to explicitly handle the reconfiguration in the code in order to retain the customized configuration. In contrast, at least one embodiment of the present disclosure can perform a three-way merge of the upgraded configuration file, a previous version configuration file, and the customized configuration file to yield a customized upgraded configuration file that retains the customized configuration after an upgrade when appropriate. As used herein, “configuration file” is inclusive of entries (such as key and value pairs) in a registry such as Windows Registry. 
     The present disclosure is not limited to particular devices or methods, which may vary. The terminology used herein is for the purpose of describing particular embodiments, and is not intended to be limiting. As used herein, the singular forms “a”, “an”, and “the” include singular and plural referents unless the content clearly dictates otherwise. Furthermore, the words “can” and “may” are used throughout this application in a permissive sense (i.e., having the potential to, being able to), not in a mandatory sense (i.e., must). The term “include,” and derivations thereof, mean “including, but not limited to.” 
     The figures herein follow a numbering convention in which the first digit or digits correspond to the drawing figure number and the remaining digits identify an element or component in the drawing. Similar elements or components between different figures may be identified by the use of similar digits. For example,  114  may reference element “14” in  FIG. 1 , and a similar element may be referenced as  214  in  FIG. 2 . As used herein, the designators “M” and “N”, particularly with respect to reference numerals in the drawings, indicates that a number of the particular feature so designated can be included. As will be appreciated, elements shown in the various embodiments herein can be added, exchanged, and/or eliminated so as to provide a number of additional embodiments of the present disclosure. In addition, as will be appreciated, the proportion and the relative scale of the elements provided in the figures are intended to illustrate certain embodiments of the present invention, and should not be taken in a limiting sense. 
       FIG. 1  is a flow chart illustrating a method of upgrading a customized configuration file according to a number of embodiments of the present disclosure. At  102 , a software installation can begin. The software can include a configuration file. In some embodiments, the configuration file can be a previous version configuration file (with respect to a later-customized configuration file), such as an original configuration file. Although an original configuration file is used as an example, embodiments are not so limited. The “original” configuration file represents any prior version configuration file. 
     At  104 , the original configuration  106  can be backed up. Backing up the original configuration file  106  can include storing a copy of the original configuration file  106  and/or storing the configuration property values contained in the original configuration file  106 . Backing up the original configuration file  106  can preserve the configuration property values contained therein for a later three-way merge  118  with other configuration property values. 
     At  108 , the configuration file can be customized. Customizing the configuration file can include receiving customized configuration property values and replacing corresponding configuration property values in the original configuration file therewith. The customized configuration property values can be received from a user, an administrator, or another source. The customized configuration property values can be specific to a computing environment in which the configuration file will be used, as opposed to what may be generic configuration property values in the original configuration file. In some embodiments, the original configuration file can include one or more null configuration property values. The configuration property values that are null in the original configuration file may not be needed in all computing environments, but may be customized for particular computing environments where specifying such values is advantageous. For example, a default configuration property value for a maximum number of connections to a database may not be provided in an original configuration file such that the default is an unlimited number of connections. However, in a particular computing environment, it may be desirable to limit the number of connections to a particular database to preserve its quality of service. 
     At  110 , an upgrade of the configuration file with a new, upgraded configuration file can be initiated. In at least one embodiment, the upgraded configuration file can be included in a new software release to which the configuration file pertains. In some embodiments, the upgraded configuration file can be a standalone upgrade (e.g., without upgrading the software underlying the configuration file). In response to the upgrade being initiated, the customized configuration file  114  can be backed up at  112 . Backing up the customized configuration file  114  can preserve the configuration property values contained therein for a later three-way merge  118  with other configuration property values. After the customized configuration file is backed up, the upgraded configuration file can replace the customized configuration file at  116 . Although backing up the original configuration file and the customized configuration file is described herein, such backup is not mandatory for all embodiments. 
     At  118  a three-way merge can be performed. In at least one embodiment, the three-way merge can be performed on the backed up original configuration file  106  (or configuration property values therefrom), the backed up custom configuration file  114  (or configuration property values therefrom) and the upgraded configuration file (e.g., in runtime of the upgraded configuration file). The algorithm for the three-way merge is described in more detail with respect to  FIG. 2 . As a result of the three-way merge algorithm, the customized configuration file can be upgraded while preserving the customization, where appropriate. For example, at least one customized configuration property value from the customized configuration file can replace a corresponding configuration property value from the upgraded configuration file to yield the final configuration file  120 . The final configuration file  120  is the state oaf the configuration file after the three-way merge is performed. As used herein, the state of the configuration file refers to the specific configuration property values contained therein. 
       FIG. 2  is a block diagram of a truth table for a three-way merge algorithm according to a number of embodiments of the present disclosure. The table includes five examples of cases illustrating application of the three-way merge algorithm to corresponding configuration property values of the original configuration file  206  (the previous version configuration file), the customized configuration file  214 , and the upgraded configuration file  222  to yield the final configuration file  220  (the customized upgraded configuration file). A configuration file can include more than one configuration property value because it can have different configuration property values for different configuration properties. As such, the configuration property values for each case illustrated in  FIG. 2  are referred to as “corresponding” because they correspond to the same configuration property. The different cases illustrated in  FIG. 2  could all correspond to different configuration properties of the same configuration file. For example, case 1 could be an IP address, case 2 could be a maximum number of database connections, case 3 could be a number of threads to be started for a service, case 4 could be a path to a directory used to store public key data, and case 5 could be a definition of a port used by a communication interface. Embodiments are not limited to these specific examples. Or, the different cases illustrated in  FIG. 2  could correspond to the same configuration property of different configuration files. For example, cases 1-5 are each respective IP addresses for different configuration files. 
     In the first case, the corresponding configuration property values of the original configuration file  206 , the customized configuration file  214 , and the upgraded configuration file  222  are all the same (e.g., “X”). When the configuration property value is static as such (e.g., where there is no customized configuration), then the final configuration property value does not change. In other words, the configuration property value of the upgraded configuration file  222  can be maintained for the final configuration file  220  (e.g., “X”). The configuration property value of the upgraded configuration file  222  is referred to as being maintained because it is the configuration property value that is in place at runtime when the three-way merge takes place, as described above. 
     In the second case, the corresponding configuration property values of the original configuration file  206  and the customized configuration file  214  are the same (e.g., “X”), but the configuration property value of the upgraded configuration file  222  is different (e.g., “Y”) than both the original configuration file  206  and the custom configuration file  214 . This case represents a static configuration property value (e.g., where there is no customized configuration), however, the configuration property value is changed by the new version. In this case, the configuration property value of the upgraded configuration file can be maintained for the final configuration file  220  (e.g., “Y”). Because there was no custom configuration, it is presumed that the user would want to adopt the upgraded value. 
     In the third case, the corresponding configuration property value of the original configuration file  206  (e.g., “X”) and the configuration property value of the customized configuration file  214  (e.g., “V”) are different. This indicates that the customized configuration file has indeed been customized for this particular configuration property value. The configuration property value of the upgraded configuration file  222  (e.g., “X”) is the same as that of the original configuration file  206 , but different than that of the customized configuration file  214 . This indicates that the new version did not update this particular configuration property value. As such, it is presumed that the user would prefer to keep the customized configuration property value for the computing environment. Thus, the configuration property value of the upgraded configuration file  222  is replaced with the configuration property value of the customized configuration file  214  to yield the configuration property value of the final configuration file  220  (e.g., “Y”). 
     In the fourth case, the corresponding configuration property value of the original configuration file  206  (e.g., “X”) and the configuration property value of the customized configuration file  214  (e.g., “Y”) are different. This indicates that the customized configuration file has indeed been customized for this particular configuration property value. The configuration property value of the upgraded configuration file  222  (e.g., “Y”) is different than that of the original configuration file  206 , but the same as the customized configuration file  214 . This may indicate that the customized configuration property value set by the user was adopted by the developer and built into the new version. In any event, for this case, the configuration property value of the updated configuration file  222  can be maintained to yield the same configuration property value for the final configuration file  220  (e.g., “Y”). This may be regarded as preserving the customization of the user. 
     In the fifth case, each of the corresponding configuration property values of the original configuration file  206  (e.g., “X”), the customized configuration file  214  (e.g., “Y”), and the upgraded configuration file  222  (e.g., “Z”) are different. This indicates that the customized configuration file has been customized for this particular configuration property value, but it was also updated differently in the new version. Accordingly, it may be presumed that the user would prefer to use the further updated configuration property value (e.g., with the new version of the software). As such, the configuration property value of the upgraded configuration file  222  can be maintained as the configuration property value of the final configuration file  220  (e.g., “Z”). 
     A method of upgrading a customized configuration file can include replacing the customized configuration file with an upgraded configuration file and comparing configuration property values of the upgraded configuration file with corresponding configuration property values of a previous version configuration file and the customized configuration file. The method can include replacing a first configuration property value of the upgraded configuration file in response to the comparison indicating that a first corresponding configuration property value of the previous version configuration file is the same as the first configuration property value of the upgraded configuration file and indicating that a first corresponding configuration property value of the customized configuration file is different than the first configuration property value of the upgraded configuration file. The method can include maintaining a second configuration property value of the upgraded configuration file in response to the comparison indicating that a second corresponding configuration property value of the previous version configuration file being the same as a second corresponding configuration property value of the customized configuration file and indicating that the second configuration property value of the upgraded configuration file being different than the second corresponding configuration property values of the previous version and the customized configuration files. 
     The method can further include maintaining a third configuration property value of the upgraded configuration file in response to the comparison indicating that the third configuration property value of the upgraded configuration file is the same as a third corresponding configuration property value of the customized configuration file and indicating that the third configuration property value of the upgraded configuration file is different than a third corresponding configuration property value of the previous version configuration file. The method can further include maintaining a fourth configuration property value of the upgraded configuration file in response to the comparison indicating that a fourth corresponding configuration property value of the customized configuration file is different than the fourth configuration property value of the upgraded configuration file, indicating that a fourth corresponding configuration property value of the previous version configuration file is different than the fourth configuration property value of the upgraded configuration file, and indicating that the fourth corresponding configuration property value of the customized configuration file is different than the fourth corresponding configuration property value of the previous version configuration file. The method can further include maintaining a fifth configuration property value of the upgraded configuration file in response to the comparison indicating that the fifth configuration property value of the upgraded configuration file is the same as a fifth corresponding configuration property value of the previous version configuration file and the same as a fifth corresponding configuration property value of the customized configuration file. 
     The method can further include customizing the previous version configuration file after backing up the previous version configuration file, backing up the customized configuration file prior to replacing the customized configuration file with the upgraded configuration file, and performing the comparison using the backup of the previous version configuration file, the backup of the customized configuration file, and the upgraded version of the configuration file. Performing the comparison can comprise performing the comparison in runtime of an application that references the customized configuration file. Customizing the previous version configuration file can comprise receiving and setting at least one configuration property value for the configuration file. 
       FIG. 3  is a block diagram of a system for upgrading a customized configuration file according to a number of embodiments of the present disclosure. The system can include a host  324  with processing resources  326  (e.g., a number of processors), memory resources  328 , and a network interface  330 . The host  324  can be coupled to a management server  342 . Although not specifically illustrated, the management server can include processing resources, memory resources, and a network interface. 
     The host  324  can be included in a software defined data center. A data center is a facility that houses servers, data storage devices, and/or other associated components such as backup power supplies, redundant data communications connections, environmental controls such as air conditioning and/or tire suppression, and/or various security systems. A data center may be maintained by an information technology (IT) service provider. An enterprise may purchase data storage and/or data processing services from the provider in order to run applications that handle the enterprises&#39; core business and operational data. The applications may be proprietary and used exclusively by the enterprise or made available through a network for anyone to access and use. A software defined data center can extend virtualization concepts such as abstraction, pooling, and automation to data center resources and services to provide information technology as a service (ITaaS). In a software defined data center, infrastructure, such as networking, processing, and security, can be virtualized and delivered as a service. A software defined data center can include software defined networking and/or software defined storage. In some embodiments, components of a software defined data center can be provisioned, operated, and/or managed through an application programming interface (API). 
     The host  324  can incorporate a hypervisor  332  that can execute a first number of virtual computing instances (VCIs)  334 - 1 ,  334 - 2 , . . . ,  334 -N (referred to generally as VCIs  334 ). VCIs, such as virtual machines, virtual workloads, data compute nodes, clusters, and containers, among others, have been introduced to lower data center capital investment in facilities and operational expenses and reduce energy consumption. A VCI is a software implementation of a computer that executes application software analogously to a physical computer. VCIs have the advantage of not being bound to physical resources, which allows VCIs to be moved around and scaled to meet changing demands of an enterprise without affecting the use of the enterprise&#39;s applications. 
     The term “virtual computing instance” covers a range of computing functionality. The term “virtual machine” refers generally to an isolated user space instance, which can be executed within a virtualized environment. Other technologies aside from hardware virtualization can provide isolated user space instances, also referred to as data compute nodes. Data compute nodes may include non-virtualized physical hosts, virtual machines (VMs), containers that run on top of a host operating system without a hypervisor or separate operating system, and/or hypervisor kernel network interface modules, among others. Hypervisor kernel network interface modules are non-VM data compute nodes that include a network stack with a hypervisor kernel network interface and receive/transmit threads. 
     The VCIs  334  can be provisioned with processing resources  326  and/or memory resources  328  and can communicate via the network interface  330 . The processing resources  326  and the memory resources  328  provisioned to the VCIs  334  can be local an or remote to the host  324 . For example, in a software defined data center, the VCIs  334  can be provisioned with resources that are generally available to the software defined data center and not tied to any particular hardware device. By way of example, the memory resources  328  can include volatile and/or non-volatile memory available to the VCIs  334 . The VCIs  334  can be moved to different hosts (not specifically illustrated), such that a different hypervisor manages the VCIs  334 . 
     VCIs  334 , in some embodiments, operate with their own guest operating systems  336  on the host  324  using processing resources  326 , memory resources  328 , and a network interface  330  of the host  324  virtualized by visualization software (e.g., a hypervisor  332 , virtual machine monitor, etc.). The tenant (i.e., the owner of the VCI  334 ) can choose which applications to operate on top of the guest operating system  336 . Some containers, on the other hand, are constructs that run on top of a host operating system without the need for a hypervisor or separate guest operating system. The host operating system can use name spaces to isolate the containers from each other and therefore can provide operating system level segregation of the different groups of applications that operate within different containers. This segregation is akin to the VM segregation that may be offered in hypervisor-virtualized environments that virtualize system hardware, and thus can be viewed as a form of virtualization that isolates different groups of applications that operate in different containers. Such containers may be more lightweight than VMs. 
     The guest operating systems  336  can include configuration files  338  as described herein. The configuration files  338  can include a plurality of configuration property values  340 - 1 ,  340 - 2 , . . .  340 -M (referred to generally as configuration property values  340 ). The management server  342  can be generally responsible for maintaining and distributing software for the VCIs  334  on hosts  324  managed by the management server  342 . In some embodiments, the management server can manage many hosts  324  and many VCIs  334  (e.g., hundreds or thousands). The management server  342  can be configured to provide an upgraded configuration file to the hypervisor  332  for a guest operating system  336  running on each of the VCIs  336 . The hypervisor  332  can be configured to replace a respective customized configuration file with the upgraded configuration file for each of the VCIs  336 . The hypervisor  332  can be configured to perform a respective three-way merge of the upgraded configuration file, a previous version configuration file, and the respective customized configuration file for each of the VCIs  336  as described with respect to  FIG. 2 . For example, the hypervisor  332  can be configured to compare configuration property values of the upgraded configuration file with corresponding configuration property values of a previous version configuration file and the respective customized configuration files. The hypervisor  332  can be configured to replace respective configuration property values of the previous version configuration file with respective customized configuration property values for each of the VCIs  334  to yield the respective customized configuration file for each of the VCIs  334 . 
     The management server  342  can be configured to back up the previous version configuration file and the upgraded configuration file. In some embodiments, the management server  342  can store various configuration files and/or configuration property values for a plurality of VCIs  334 . The management server can be configured to provide the backup previous version configuration file to the hypervisor  332  with the upgraded configuration file for the three-way merge. 
       FIG. 4  is a diagram of a system for upgrading a customized configuration file according to a number of embodiments of the present disclosure. The system  450  can include a storage location  458 , a subsystem  452 , and/or a number of engines, for example configuration property value replacement engine  454  and/or configuration property value maintenance engine  456  and can be in communication with the storage location  458  via a communication link. The system  450  can include additional or fewer engines than illustrated to perform the various functions described herein. The system can represent program instructions and/or hardware of a machine (e.g., machine  560  as referenced in  FIG. 5 , etc.). As used herein, an “engine” can include program instructions and/or hardware, but at least includes hardware. Hardware is a physical component of a machine that enables it to perform a function. Examples of hardware can include a processing resource, a memory resource, a logic gate, etc. 
     The number of engines can include a combination of hardware and program instructions that is configured to perform a number of functions described herein. The program instructions (e.g., software, firmware, etc.) can be stored in a memory resource (e.g., machine-readable medium) as well as hard-wired program (e.g., logic). Hard-wired program instructions (e.g., logic) can be considered as both program instructions and hardware. 
     In some embodiments, the configuration property value replacement engine  454  can include a combination of hardware and program instructions that is configured to replace the customized configuration file with an upgraded configuration file. The configuration property value replacement engine  454  can include a combination of hardware and program instructions that is configured to replace the configuration property value of the upgraded configuration file with the corresponding configuration property value of the customized configuration file in response to the configuration property value of the upgraded configuration file being the same as the corresponding configuration property value of the previous version configuration file and in response to the configuration property value of the upgraded configuration file being different than the corresponding configuration property value of the customized configuration file. 
     In some embodiments, the configuration property value maintenance engine  456  can include a combination of hardware and program instructions that is configured to maintain a configuration property value of the upgraded configuration file in response to a corresponding configuration property value of the customized configuration file being different than the configuration property value of the upgraded configuration file, a corresponding configuration property value of a previous version configuration file being different than the configuration property value of the upgraded configuration file, and the corresponding configuration property value of the customized configuration file being different thin the corresponding configuration property value of the previous version configuration file. 
     The configuration property value maintenance engine  456  can include a combination of hardware and program instructions that is configured to maintain the configuration property value of the upgraded configuration file in response to the corresponding configuration property value of the previous version configuration file being the same as the corresponding configuration property value of the customized configuration file and in response to the configuration property value of the upgraded configuration file being different than the corresponding configuration property values of the previous version and the customized configuration files. 
     The configuration property value maintenance engine  456  can include combination of hardware and program instructions that is configured to maintain the configuration property value of the upgraded configuration file in response to the corresponding configuration property value of the customized configuration file being the same as the configuration property value of the upgraded configuration file. The instructions to maintain the configuration property value of the upgraded configuration file in response to the corresponding configuration property value of the customized configuration file being the same as the configuration property value of the upgraded configuration file further comprise instructions to maintain the configuration property value of the upgraded configuration file regardless of whether the corresponding configuration property value of the previous version configuration file is different than the configuration property value of the upgraded configuration file. 
     The configuration property value maintenance engine  456  can include a combination of hardware and program instructions that is configured to maintain the configuration property value of the upgraded configuration file in response to an absence of the corresponding configuration property value of the previous version configuration file. 
       FIG. 5  is a diagram of a machine for upgrading a customized configuration file according to a number of embodiments of the present disclosure. The machine  560  can utilize software, hardware, firmware, and/or logic to perform a number of functions. The machine  560  can be a combination of hardware and program instructions configured to perform a number of functions (e.g., actions). The hardware, for example, can include a number of processing resources  526  and a number of memory resources  528 , such as a machine-readable medium (MRM) or other memory resources  528 . The memory resources  528  can be internal and/or external to the machine  560  (e.g., the machine  560  can include internal memory resources and have access to external memory resources). In some embodiments, the machine  560  can be a VCI. The program instructions (e.g., machine-readable instructions (MRI)) can include instructions stored on the MRM to implement a particular function (e.g., an action such as upgrading a customized configuration file). The set of MRI can be executable by one or more of the processing resources  526 . The memory resources  528  can be coupled to the machine  560  in a wired and/or wireless manner. For example, the memory resources  528  can be an internal memory, a portable memory, a portable disk, and/or a memory associated with another resource, e.g., enabling MRI to be transferred and/or executed across a network such as the Internet. As used herein, a “module” can include program instructions and/or hardware, but at least includes program instructions. 
     Memory resources  528  can be non-transitory and can include volatile and/or non-volatile memory. Volatile memory can include memory that depends upon power to store information, such as various types of dynamic random access memory (DRAM) among others. Non-volatile memory can include memory that does not depend upon power to store information. Examples of non-volatile memory can include solid state media such as flash memory, electrically erasable programmable read-only memory (EEPROM), phase change random access memory (PCRAM), magnetic memory, optical memory, and/or a solid state drive (SSD), etc., as well as other types of machine-readable media. 
     The processing resources  526  can be coupled to the memory resources  528  via a communication path  566 . The communication path  566  can be local or remote to the machine  560 . Examples of a local communication path  566  can include an electronic bus internal to a machine, where the memory resources  528  are in communication with the processing resources  526  via the electronic bus. Examples of such electronic buses can include Industry Standard Architecture (ISA), Peripheral Component Interconnect (PCI), Technology Attachment (ATA), Small Computer System Interface (SCSI), Universal Serial Bus (USB), among other types of electronic buses and variants thereof. The communication path  566  can be such that the memory resources  528  are remote from the processing resources  526 , such as in a network connection between the memory resources  528  and the processing resources  526 . That is, the communication path  566  can be a network connection. Examples of such a network connection can include a local area network (LAN), wide area network (WAN), personal area network (PAN), and the Internet, among others. 
     As shown in  FIG. 5 , the MRI stored in the memory resources  528  can be segmented into a number of modules  562 ,  564  that when executed by the processing resources  526  can perform a number of functions. As used herein a module includes a set of instructions included to perform a particular task or action. The number of modules  562 ,  564  can be sub-modules of other modules. For example, the configuration property value replacement module  562  can be a sub-module of the configuration property value maintenance module  564  and/or can be contained within a single module. Furthermore, the number of modules  562 ,  564  can comprise individual modules separate and distinct from one another. Examples are not limited to the specific modules  562 ,  564  illustrated in  FIG. 5 . 
     Each of the number of modules  562 ,  564  can include program instructions and/or a combination of hardware and program instructions that, when executed by a processing resource  526 , can function as a corresponding engine as described with respect to  FIG. 4 . For example, the configuration property value replacement module  562  can include program instructions and/or a combination of hardware and program instructions that, when executed by a processing resource  526 , can function as the configuration property value replacement engine  454  and/or the configuration property value maintenance module  564  can include program instructions and/or a combination of hardware and program instructions that, when executed by a processing resource  526 , can function as the configuration property value maintenance engine  456 . 
     Although specific embodiments have been described above, these embodiments are not intended to limit the scope of the present disclosure, even where only a single embodiment is described with respect to a particular feature. Examples of features provided in the disclosure are intended to be illustrative rather than restrictive unless stated otherwise. The above description is intended to cover such alternatives, modifications, and equivalents as would be apparent to a person skilled in the art having the benefit of this disclosure. 
     The scope of the present disclosure includes any feature or combination of features disclosed herein (either explicitly or implicitly), or any generalization thereof, whether or not it mitigates any or all of the problems addressed herein. Various advantages of the present disclosure have been described herein, but embodiments may provide some, all, or none of such advantages, or may provide other advantages. 
     In the foregoing Detailed Description, some features, are grouped together in a single embodiment for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the disclosed embodiments of the present disclosure have to use more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus, the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separate embodiment.