Patent Publication Number: US-9900374-B2

Title: Application bundle management across mixed file system types

Description:
The following disclosure(s) are submitted under 35 U.S.C. 102(b)( 1 )(A): An open invitation to beta-test IBM InfoSphere Streams, Oct. 20, 2014. 
     BACKGROUND 
     This disclosure relates generally to computer systems and, more particularly, relates to stream computing. Database systems are typically configured to separate the process of storing data from accessing, manipulating, or using data stored in a database. More specifically, database systems use a model in which data is first stored and indexed in a memory before subsequent querying and analysis. In general, database systems may not be well suited for performing real-time processing and analyzing streaming data. In particular, database systems may be unable to store, index, and analyze large amounts of streaming data efficiently or in real time. 
     SUMMARY 
     Aspects of the disclosure include managing a file system having a cluster of compute nodes to process a stream of tuples using an application bundle. A cluster bundle directory is established on the cluster of compute nodes. A host bundle library is established on a first compute node of the cluster of compute nodes. The stream of tuples to be processed by a plurality of processing elements operating on the cluster of compute nodes including the first compute node is received. Using the cluster bundle directory, it is detected that the application bundle is not installed on the first compute node. Using both the cluster bundle directory and the host bundle library, a determination is made to initiate a sourcing operation with respect to the application bundle. In response to initiating the sourcing operation, the stream of tuples is processed using the application bundle. 
     Aspects of the disclosure include a multilevel directory/library structure having a global directory for a cluster of compute nodes and a local library on hosts (e.g., one or more hosts). The global directory has information with respect to which hosts have an application bundle installed in them and the local library has information with respect to which hosts share application bundle(s). Hosts have access to a local library (e.g., host bundle library) somewhere in the cluster, but it may not be unique to that local host, as one or more hosts may share the local library. Hosts can determine which other hosts are sharing by examining the host catalog section. Hosts can register its intended use of the local library at start-up (e.g., by signing its host identifier into the host catalog section). If the application bundle is shared by other hosts, it can be identified via the registration entries. A bundle controller can use the information to determine sourcing operations with respect to sharing or installation (e.g., sharing a particular application bundle in response to the particular application bundle being installed). Aspects of the disclosure may provide performance or efficiency benefits when managing one or more application bundles (e.g., speed, flexibility, responsiveness, resource usage). 
     The above summary is not intended to describe each illustrated embodiment or every implementation of the present disclosure. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The drawings included in the present application are incorporated into, and form part of, the specification. They illustrate embodiments of the present disclosure and, along with the description, serve to explain the principles of the disclosure. The drawings are only illustrative of certain embodiments and do not limit the disclosure. 
         FIG. 1  illustrates a computing infrastructure configured to execute a stream computing application according to various embodiments. 
         FIG. 2  illustrates a more detailed view of a compute node of  FIG. 1  according to various embodiments. 
         FIG. 3  illustrates a more detailed view of the management system of  FIG. 1  according to various embodiments. 
         FIG. 4  illustrates a more detailed view of the compiler system of  FIG. 1  according to various embodiments. 
         FIG. 5  illustrates an operator graph for a stream computing application according to various embodiments. 
         FIG. 6  shows an example system for using application bundle management with respect to executing a stream computing application according to embodiments. 
         FIG. 7  is a flowchart illustrating a method for processing a stream of tuples using an application bundle according to embodiments. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention. 
     DETAILED DESCRIPTION 
     Aspects of the disclosure include a multilevel directory/library structure having a global directory for a cluster of compute nodes and a local library on hosts (e.g., one or more hosts). The global directory has information with respect to which hosts have an application bundle installed in them and the local library has information with respect to which hosts share application bundle(s). Hosts have access to a local library (e.g., host bundle library) somewhere in the cluster, but it may not be unique to that local host, as one or more hosts may share the local library. Hosts can determine which other hosts are sharing by examining the host catalog section. Hosts can register its intended use of the local library at start-up (e.g., by signing its host identifier into the host catalog section). If the application bundle is shared by other hosts, it can be identified via the registration entries. A bundle controller can use the information to determine sourcing operations with respect to sharing or installation (e.g., sharing a particular application bundle in response to the particular application bundle being installed). Aspects of the disclosure may provide performance or efficiency benefits when managing one or more application bundles (e.g., speed, flexibility, responsiveness, resource usage). 
     Stream-based computing and stream-based database computing are emerging as a developing technology for database systems. Products are available which allow users to create applications that process and query streaming data before it reaches a database file. With this emerging technology, users can specify processing logic to apply to inbound data records while they are “in flight,” with the results available in a very short amount of time, often in fractions of a second. Constructing an application using this type of processing has opened up a new programming paradigm that will allow for development of a broad variety of innovative applications, systems, and processes, as well as present new challenges for application programmers and database developers. 
     In a stream computing application, stream operators are connected to one another such that data flows from one stream operator to the next (e.g., over a TCP/IP socket). When a stream operator receives data, it may perform operations, such as analysis logic, which may change the tuple by adding or subtracting attributes, or updating the values of existing attributes within the tuple. When the analysis logic is complete, a new tuple is then sent to the next stream operator. Scalability is achieved by distributing an application across nodes by creating executables (i.e., processing elements), as well as replicating processing elements on multiple nodes and load balancing among them. Stream operators in a stream computing application can be fused together to form a processing element that is executable. Doing so allows processing elements to share a common process space, resulting in much faster communication between stream operators than is available using inter-process communication techniques (e.g., using a TCP/IP socket). Further, processing elements can be inserted or removed dynamically from an operator graph representing the flow of data through the stream computing application. A particular stream operator may not reside within the same operating system process as other stream operators. In addition, stream operators in the same operator graph may be hosted on different nodes, e.g., on different compute nodes or on different cores of a compute node. 
     Data flows from one stream operator to another in the form of a “tuple.” A tuple is a sequence of one or more attributes associated with an entity. Attributes may be any of a variety of different types, e.g., integer, float, Boolean, string, etc. The attributes may be ordered. In addition to attributes associated with an entity, a tuple may include metadata, i.e., data about the tuple. A tuple may be extended by adding one or more additional attributes or metadata to it. As used herein, “stream” or “data stream” refers to a sequence of tuples. Generally, a stream may be considered a pseudo-infinite sequence of tuples. 
     Tuples are received and output by stream operators and processing elements. An input tuple corresponding with a particular entity that is received by a stream operator or processing element, however, is generally not considered to be the same tuple that is output by the stream operator or processing element, even if the output tuple corresponds with the same entity or data as the input tuple. An output tuple need not be changed in some way from the input tuple. 
     Nonetheless, an output tuple may be changed in some way by a stream operator or processing element. An attribute or metadata may be added, deleted, or modified. For example, a tuple will often have two or more attributes. A stream operator or processing element may receive the tuple having multiple attributes and output a tuple corresponding with the input tuple. The stream operator or processing element may only change one of the attributes so that all of the attributes of the output tuple except one are the same as the attributes of the input tuple. 
     Generally, a particular tuple output by a stream operator or processing element may not be considered to be the same tuple as a corresponding input tuple even if the input tuple is not changed by the processing element. However, to simplify the present description and the claims, an output tuple that has the same data attributes or is associated with the same entity as a corresponding input tuple will be referred to herein as the same tuple unless the context or an express statement indicates otherwise. 
     Stream computing applications handle massive volumes of data that need to be processed efficiently and in real time. For example, a stream computing application may continuously ingest and analyze hundreds of thousands of messages per second and up to petabytes of data per day. Accordingly, each stream operator in a stream computing application may be required to process a received tuple within fractions of a second. Unless the stream operators are located in the same processing element, it is necessary to use an inter-process communication path each time a tuple is sent from one stream operator to another. Inter-process communication paths can be a critical resource in a stream computing application. According to various embodiments, the available bandwidth on one or more inter-process communication paths may be conserved. Efficient use of inter-process communication bandwidth can speed up processing. 
     A streams processing job has a directed graph of processing elements that send data tuples between the processing elements. The processing element operates on the incoming tuples, and produces output tuples. A processing element has an independent processing unit and runs on a host. The streams platform can be made up of a collection of hosts that are eligible for processing elements to be placed upon. When a job is submitted to the streams run-time, the platform determines the desired placement of the processing elements in the job and schedules the processing elements for execution on the decided host. Each host in the cluster may have zero or more processing elements placed for execution. 
     In order for the processing element to be run on a host, access is had to its associated application binaries (application bundles). A streams processing application may be executed on a potentially large set of hosts. When a new job is submitted into the system, the associated application bundle is to be made available to all hosts that will run this aspect. Availability can be performed by provisioning (e.g., file transfer) of the application bundle to the desired hosts, or by placing the application bundle in a shared file system location that is accessible to the target hosts. Application bundles can be relatively large, so there is a measurable cost of moving application bundles between hosts and for storing them on a host. 
     Provisioned application bundles and shared file application bundles both have performance or efficiency impacts based on particular configurations. Provisioned application bundles can include efficient storage access speed and local control while consuming resources when provisioning and in storage redundancies. Shared application bundles can efficiently use storage and efficiently start-up while management, maintenance, and file access speeds may present challenges. Whether or not to use a shared or non-shared file system may have performance or efficiency benefits if it is a host independent choice. 
     For example, while the cluster administrator may select to use shared file system wherever possible, some hosts may have limited capability for using the shared file system. Some hosts may have limited storage, so those hosts may desire to use a shared file system location. Also, individual hosts may not want to make a host-wide decision of which file system type to use. Individualized choices for each of the file system segments that it has can be utilized (e.g., some shared, some not shared). Regardless that the choice is made independently by each host, the knowledge of which choice was made can be communicated throughout the cluster. As such, the application bundles may be managed differently if they are shared or not shared. 
     Application bundles may be handled by a group of operations. When a processing element is started, a bundle controller can determine if the related application bundle already exists on this host. If the bundle controller determines it is not on this host, it can determine if it already exists in shared storage and therefore does not need to be installed into the storage. Also, the bundle controller can determine if it is a new request to this host and the application bundle is to be downloaded into its storage. In embodiments where the application bundle is installed within a shared file system, possible file latency may be desired to be accounted for. When a processing element is terminated, the bundle controller may determine if the application bundle can be uninstalled (or not uninstalled if there a sharing host that still needs it). 
     A cluster-wide, master application bundle directory can be maintained having a directory of install hosts for every application bundle, a set of hosts that share the application bundle storage, and a methodology for describing the application bundle storage. For instance, there may be multiple application bundle storage units per host, with different sharing partners. For example, the application bundle storage may include a computer network address for the shared file system server along with a relative file system path (the absolute file system path may be different on each host, but still sharing via relative paths, whose root location can be host dependent). 
     A determination can be made as to whether file latency has been accounted for on shared application bundle storage locations. File data latency can occur on shared file systems, where the data is present in one view of the file system data on one system, but it may not be fully available yet on a different host that is sharing this file system. To implement and maintain a master application bundle directory can have challenges. Each host administrator may be required to communicate with other host administrators to determine the shared file system configuration and gain assent on an application bundle storage format and contents to use to describe it. If a particular host administrator decides to change its configuration, communicate of these changes would then occur. As such, challenges are presented such as a burdensome master cluster directory implementation, close communication between cluster host administrators, burdensome maintenance operations to master cluster directory such as adding a new file system segment to a subset of hosts that will be shared, or manual maintenance of configuration having a risk of error. 
     Aspects of the multilevel directory/library structure disclosed herein can address the challenges of the cluster-wide, master application bundle directory. Aspects of the disclosure may provide performance or efficiency benefits when managing one or more application bundles using a multilevel directory/library structure having a global directory for a cluster of compute nodes and a local library on hosts. Such performance or efficiency benefits can be related to speed, flexibility, responsiveness, or resource usage. 
       FIG. 1  illustrates one exemplary computing infrastructure  100  that may be configured to execute a stream computing application, according to some embodiments. The computing infrastructure  100  includes a management system  105  and two or more compute nodes  110 A- 110 D—i.e., hosts—which are communicatively coupled to each other using one or more communications networks  120 . The communications network  120  may include one or more servers, networks, or databases, and may use a particular communication protocol to transfer data between the compute nodes  110 A- 110 D. A compiler system  102  may be communicatively coupled with the management system  105  and the compute nodes  110  either directly or via the communications network  120 . 
     The communications network  120  may include a variety of types of physical communication channels or “links.” The links may be wired, wireless, optical, or any other suitable media. In addition, the communications network  120  may include a variety of network hardware and software for performing routing, switching, and other functions, such as routers, switches, or bridges. The communications network  120  may be dedicated for use by a stream computing application or shared with other applications and users. The communications network  120  may be any size. For example, the communications network  120  may include a single local area network or a wide area network spanning a large geographical area, such as the Internet. The links may provide different levels of bandwidth or capacity to transfer data at a particular rate. The bandwidth that a particular link provides may vary depending on a variety of factors, including the type of communication media and whether particular network hardware or software is functioning correctly or at full capacity. In addition, the bandwidth that a particular link provides to a stream computing application may vary if the link is shared with other applications and users. The available bandwidth may vary depending on the load placed on the link by the other applications and users. The bandwidth that a particular link provides may also vary depending on a temporal factor, such as time of day, day of week, day of month, or season. 
       FIG. 2  is a more detailed view of a compute node  110 , which may be the same as one of the compute nodes  110 A- 110 D of  FIG. 1 , according to various embodiments. The compute node  110  may include, without limitation, one or more processors (CPUs)  205 , a network interface  215 , an interconnect  220 , a memory  225 , and a storage  230 . The compute node  110  may also include an I/O device interface  210  used to connect I/O devices  212 , e.g., keyboard, display, and mouse devices, to the compute node  110 . 
     Each CPU  205  retrieves and executes programming instructions stored in the memory  225  or storage  230 . Similarly, the CPU  205  stores and retrieves application data residing in the memory  225 . The interconnect  220  is used to transmit programming instructions and application data between each CPU  205 , I/O device interface  210 , storage  230 , network interface  215 , and memory  225 . The interconnect  220  may be one or more busses. The CPUs  205  may be a single CPU, multiple CPUs, or a single CPU having multiple processing cores in various embodiments. In one embodiment, a processor  205  may be a digital signal processor (DSP). One or more processing elements  235  (described below) may be stored in the memory  225 . A processing element  235  may include one or more stream operators  240  (described below). In one embodiment, a processing element  235  is assigned to be executed by only one CPU  205 , although in other embodiments the stream operators  240  of a processing element  235  may include one or more threads that are executed on two or more CPUs  205 . The memory  225  is generally included to be representative of a random access memory, e.g., Static Random Access Memory (SRAM), Dynamic Random Access Memory (DRAM), or Flash. The storage  230  is generally included to be representative of a non-volatile memory, such as a hard disk drive, solid state device (SSD), or removable memory cards, optical storage, flash memory devices, network attached storage (NAS), or connections to storage area network (SAN) devices, or other devices that may store non-volatile data. The network interface  215  is configured to transmit data via the communications network  120 . 
     A stream computing application may include one or more stream operators  240  that may be compiled into a “processing element” container  235 . The memory  225  may include two or more processing elements  235 , each processing element having one or more stream operators  240 . Each stream operator  240  may include a portion of code that processes tuples flowing into a processing element and outputs tuples to other stream operators  240  in the same processing element, in other processing elements, or in both the same and other processing elements in a stream computing application. Processing elements  235  may pass tuples to other processing elements that are on the same compute node  110  or on other compute nodes that are accessible via communications network  120 . For example, a processing element  235  on compute node  110 A may output tuples to a processing element  235  on compute node  110 B. 
     The storage  230  may include a buffer  260 . Although shown as being in storage, the buffer  260  may be located in the memory  225  of the compute node  110  or in a combination of both memories. Moreover, storage  230  may include storage space that is external to the compute node  110 , such as in a cloud. 
     The compute node  110  may include one or more operating systems  262 . An operating system  262  may be stored partially in memory  225  and partially in storage  230 . Alternatively, an operating system may be stored entirely in memory  225  or entirely in storage  230 . The operating system provides an interface between various hardware resources, including the CPU  205 , and processing elements and other components of the stream computing application. In addition, an operating system provides common services for application programs, such as providing a time function. 
       FIG. 3  is a more detailed view of the management system  105  of  FIG. 1  according to some embodiments. The management system  105  may include, without limitation, one or more processors (CPUs)  305 , a network interface  315 , an interconnect  320 , a memory  325 , and a storage  330 . The management system  105  may also include an I/O device interface  310  connecting I/O devices  312 , e.g., keyboard, display, and mouse devices, to the management system  105 . 
     Each CPU  305  retrieves and executes programming instructions stored in the memory  325  or storage  330 . Similarly, each CPU  305  stores and retrieves application data residing in the memory  325  or storage  330 . The interconnect  320  is used to move data, such as programming instructions and application data, between the CPU  305 , I/O device interface  310 , storage unit  330 , network interface  315 , and memory  325 . The interconnect  320  may be one or more busses. The CPUs  305  may be a single CPU, multiple CPUs, or a single CPU having multiple processing cores in various embodiments. In one embodiment, a processor  305  may be a DSP. Memory  325  is generally included to be representative of a random access memory, e.g., SRAM, DRAM, or Flash. The storage  330  is generally included to be representative of a non-volatile memory, such as a hard disk drive, solid state device (SSD), removable memory cards, optical storage, Flash memory devices, network attached storage (NAS), connections to storage area-network (SAN) devices, or the cloud. The network interface  315  is configured to transmit data via the communications network  120 . 
     The memory  325  may store a stream manager  134 . Additionally, the storage  330  may store an operator graph  335 . The operator graph  335  may define how tuples are routed to processing elements  235  ( FIG. 2 ) for processing. 
     The management system  105  may include one or more operating systems  332 . An operating system  332  may be stored partially in memory  325  and partially in storage  330 . Alternatively, an operating system may be stored entirely in memory  325  or entirely in storage  330 . The operating system provides an interface between various hardware resources, including the CPU  305 , and processing elements and other components of the stream computing application. In addition, an operating system provides common services for application programs, such as providing a time function. 
       FIG. 4  is a more detailed view of the compiler system  102  of  FIG. 1  according to some embodiments. The compiler system  102  may include, without limitation, one or more processors (CPUs)  405 , a network interface  415 , an interconnect  420 , a memory  425 , and storage  430 . The compiler system  102  may also include an I/O device interface  410  connecting I/O devices  412 , e.g., keyboard, display, and mouse devices, to the compiler system  102 . 
     Each CPU  405  retrieves and executes programming instructions stored in the memory  425  or storage  430 . Similarly, each CPU  405  stores and retrieves application data residing in the memory  425  or storage  430 . The interconnect  420  is used to move data, such as programming instructions and application data, between the CPU  405 , I/O device interface  410 , storage unit  430 , network interface  415 , and memory  425 . The interconnect  420  may be one or more busses. The CPUs  405  may be a single CPU, multiple CPUs, or a single CPU having multiple processing cores in various embodiments. In one embodiment, a processor  405  may be a DSP. Memory  425  is generally included to be representative of a random access memory, e.g., SRAM, DRAM, or Flash. The storage  430  is generally included to be representative of a non-volatile memory, such as a hard disk drive, solid state device (SSD), removable memory cards, optical storage, flash memory devices, network attached storage (NAS), connections to storage area-network (SAN) devices, or to the cloud. The network interface  415  is configured to transmit data via the communications network  120 . 
     The compiler system  102  may include one or more operating systems  432 . An operating system  432  may be stored partially in memory  425  and partially in storage  430 . Alternatively, an operating system may be stored entirely in memory  425  or entirely in storage  430 . The operating system provides an interface between various hardware resources, including the CPU  405 , and processing elements and other components of the stream computing application. In addition, an operating system provides common services for application programs, such as providing a time function. 
     The memory  425  may store a compiler  136 . The compiler  136  compiles modules, which include source code or statements, into the object code, which includes machine instructions that execute on a processor. In one embodiment, the compiler  136  may translate the modules into an intermediate form before translating the intermediate form into object code. The compiler  136  may output a set of deployable artifacts that may include a set of processing elements and an application description language file (ADL file), which is a configuration file that describes the stream computing application. In some embodiments, the compiler  136  may be a just-in-time compiler that executes as part of an interpreter. In other embodiments, the compiler  136  may be an optimizing compiler. In various embodiments, the compiler  136  may perform peephole optimizations, local optimizations, loop optimizations, inter-procedural or whole-program optimizations, machine code optimizations, or any other optimizations that reduce the amount of time required to execute the object code, to reduce the amount of memory required to execute the object code, or both. The output of the compiler  136  may be represented by an operator graph, e.g., the operator graph  335 . 
     The compiler  136  may also provide the application administrator with the ability to optimize performance through profile-driven fusion optimization. Fusing operators may improve performance by reducing the number of calls to a transport. While fusing stream operators may provide faster communication between operators than is available using inter-process communication techniques, any decision to fuse operators requires balancing the benefits of distributing processing across multiple compute nodes with the benefit of faster inter-operator communications. The compiler  136  may automate the fusion process to determine how to best fuse the operators to be hosted by one or more processing elements, while respecting user-specified constraints. This may be a two-step process, including compiling the application in a profiling mode and running the application, then re-compiling and using the optimizer during this subsequent compilation. The end result may, however, be a compiler-supplied deployable application with an optimized application configuration. 
       FIG. 5  illustrates an exemplary operator graph  500  for a stream computing application beginning from one or more sources  135  through to one or more sinks  504 ,  506 , according to some embodiments. This flow from source to sink may also be generally referred to herein as an execution path. In addition, a flow from one processing element to another may be referred to as an execution path in various contexts. Although  FIG. 5  is abstracted to show connected processing elements PE 1 -PE 10 , the operator graph  500  may include data flows between stream operators  240  ( FIG. 2 ) within the same or different processing elements. Typically, processing elements, such as processing element  235  ( FIG. 2 ), receive tuples from the stream as well as output tuples into the stream (except for a sink—where the stream terminates, or a source—where the stream begins). While the operator graph  500  includes a relatively small number of components, an operator graph may be much more complex and may include many individual operator graphs that may be statically or dynamically linked together. 
     The example operator graph shown in  FIG. 5  includes ten processing elements (labeled as PE 1 -PE 10 ) running on the compute nodes  110 A- 110 D. A processing element may include one or more stream operators fused together to form an independently running process with its own process ID (PID) and memory space. In cases where two (or more) processing elements are running independently, inter-process communication may occur using a “transport,” e.g., a network socket, a TCP/IP socket, or shared memory. Inter-process communication paths used for inter-process communications can be a critical resource in a stream computing application. However, when stream operators are fused together, the fused stream operators can use more rapid communication techniques for passing tuples among stream operators in each processing element. 
     The operator graph  500  begins at a source  135  and ends at a sink  504 ,  506 . Compute node  110 A includes the processing elements PE 1 , PE 2 , and PE 3 . Source  135  flows into the processing element PE 1 , which in turn outputs tuples that are received by PE 2  and PE 3 . For example, PE 1  may split data attributes received in a tuple and pass some data attributes in a new tuple to PE 2 , while passing other data attributes in another new tuple to PE 3 . As a second example, PE 1  may pass some received tuples to PE 2  while passing other tuples to PE 3 . Tuples that flow to PE 2  are processed by the stream operators contained in PE 2 , and the resulting tuples are then output to PE 4  on compute node  110 B. Likewise, the tuples output by PE 4  flow to operator sink PE 6   504 . Similarly, tuples flowing from PE 3  to PE 5  also reach the operators in sink PE 6   504 . Thus, in addition to being a sink for this example operator graph, PE 6  could be configured to perform a join operation, combining tuples received from PE 4  and PE 5 . This example operator graph also shows tuples flowing from PE 3  to PE 7  on compute node  110 C, which itself shows tuples flowing to PE 8  and looping back to PE 7 . Tuples output from PE 8  flow to PE 9  on compute node  110 D, which in turn outputs tuples to be processed by operators in a sink processing element, for example PE 10   506 . 
     Processing elements  235  ( FIG. 2 ) may be configured to receive or output tuples in various formats, e.g., the processing elements or stream operators could exchange data marked up as XML documents. Furthermore, each stream operator  240  within a processing element  235  may be configured to carry out any form of data processing functions on received tuples, including, for example, writing to database tables or performing other database operations such as data joins, splits, reads, etc., as well as performing other data analytic functions or operations. 
     The stream manager  134  of  FIG. 1  may be configured to monitor a stream computing application running on compute nodes, e.g., compute nodes  110 A- 110 D, as well as to change the deployment of an operator graph, e.g., operator graph  132 . The stream manager  134  may move processing elements from one compute node  110  to another, for example, to manage the processing loads of the compute nodes  110 A- 110 D in the computing infrastructure  100 . Further, stream manager  134  may control the stream computing application by inserting, removing, fusing, un-fusing, or otherwise modifying the processing elements and stream operators (or what tuples flow to the processing elements) running on the compute nodes  110 A- 110 D. 
     Because a processing element may be a collection of fused stream operators, it is equally correct to describe the operator graph as one or more execution paths between specific stream operators, which may include execution paths to different stream operators within the same processing element.  FIG. 5  illustrates execution paths between processing elements for the sake of clarity. 
       FIG. 6  shows an example system  600  for using application bundle management with respect to executing a stream computing application according to embodiments. The example system  600  can include a mixed file system type (e.g., shared/non-shared). Aspects of the example system  600  may implement a multi-level directory structure. The multi-level directory structure can include a global directory/library/catalog for cluster and local directory/library/catalog on each host. The multi-level directory structure may be constructed as part of a management system  605 , compute nodes  610 A/ 610 B/ 610 C/ 610 D, and with respect to network  602 . 
     A local directory (e.g., host bundle library  611 D,  611 A) has information with respect to which hosts share application bundle(s) and can include self-registration section for sharing hosts (e.g., host identifiers  616 /hosts catalog  618 ). In embodiments, the local directory may be shared by a plurality of hosts (e.g., host bundle library  611 BC which can be shared by compute nodes  610 B,  610 C and may illustratively have library data storage on compute node  610 B accessible by compute node  610 C without library data storage on compute node  610 C). Hosts can register its intended use of the local library at start-up (e.g., by signing its host identifier into the host catalog section). If the application bundle is shared by other hosts, it can be detected/identified via the registration entries (e.g., hosts can determine which other hosts are sharing by examining the host catalog section). A bundle controller of the management system  605  can use local directory sharing information (e.g., bundle identifiers  612 ) to determine sharing sets (which use bundle images  614 ) or sourcing operations with respect to sharing or installation (e.g., sharing a particular application bundle in response to the particular application bundle being installed). The bundle controller can also use such information in a manner consistent with the global application bundle directory information (e.g., cluster bundle directory  620  having bundle identifiers  622 /host identifiers  624 ). 
     For instance, the cluster bundle directory  620  may be stored in one location and can include the bundle identifiers  622  (e.g., names for particular application bundles) and host identifiers  624  (e.g., a list of hosts that application bundle has been installed on). To illustrate, a first record may have AB#1 on HostD &amp; HostB; a second record may have AB#2 on HostC &amp; HostD; a third record may have AB#3 on HostD &amp; HostB; and, a fourth record may have AB#4 on HostC. The host bundle library  611 D may have the host identifiers  616  which indicate hosts that are using the application bundle library  611 D (e.g., sharing hosts for a shared file system), the hosts catalog  618  which can include a file named for the using hosts (e.g., HostD, HostB), the bundle identifiers  612  (e.g., AB#1, AB#2, AB#3), and the bundle images  614  (e.g., Image1, Image2, Image3). As such, HostC may have a separate host bundle library. In embodiments, the first host to be initiated may create the host bundle library (for the shared file system). In certain embodiments, the host identifiers  616  and the hosts catalog  618  may be a single component (e.g., one data object). 
     Accordingly, aspects of example system  600  may provide performance or efficiency benefits (e.g., speed, flexibility, responsiveness, resource usage) when managing an application bundle. Aspects can be implemented locally in an efficient manner. Global communication between cluster host administrators may be positively impacted. File storage configurations, and communications pertaining to such, may be efficiently performed. Multiple file storage segments per host can be supported for performance or efficiency benefits. 
     Consider an operative example where both the cluster bundle directory and the host bundle library have been established. Reception of stream of tuples to be processed by a plurality of processing elements operating on the cluster of compute nodes including the first compute node can occur. It can be detected, using the cluster bundle directory, that the application bundle desired for processing the stream of tuples is not installed on the first compute node. If none of the sharing hosts in the host bundle library are listed in the cluster bundle directory as having the application bundle, the application bundle is downloaded to the first compute node from a non-sharing host listed in the cluster bundle directory. If a sharing host in the host bundle library is listed in the cluster bundle directory as having the application bundle, the application bundle may be sourced via sharing. 
       FIG. 7  is a flowchart illustrating a method  700  for processing a stream of tuples using an application bundle according to embodiments. Aspects of method  700  can manage a file system having a cluster of compute nodes to process a stream of tuples using an application bundle. Aspects can include a directory available across all hosts to indicate which bundles are on which hosts and a library on each host itself to indicate which hosts are being shared. In certain embodiments, user/administrator/host may have a choice for a file system unique to itself or to a shared configuration. Method  700  may begin at block  701 . 
     At block  710 , a cluster bundle directory is established. The cluster bundle directory is established on the cluster of compute nodes. For example, in one location separate from a plurality of compute nodes and associated with an application bundle controller (e.g., on the same system as the application bundle controller). In embodiments, the cluster bundle directory indicates installation of at least one application bundle on a subgroup of the cluster of compute nodes at block  715 . For instance, if the cluster has 10 nodes, 3 of those nodes may have one or more application bundles installed. 
     The cluster bundle directory may be maintained at a cluster level. It can be accessible to a plurality of (e.g., all) hosts in the cluster. The cluster bundle directory may identify/detail where (e.g., which compute nodes) one or more application bundles are currently installed at. In certain embodiments, it may keep historical data which can serve as a predictive baseline with respect to particular jobs/tasks. As one or more application bundles are installed/uninstalled in the various compute nodes of the cluster, the cluster bundle directory may be updated (see herein). 
     At block  720 , a host bundle library is established. The host bundle library is established on a first compute node of the cluster of compute nodes. A plurality (e.g., each) of the cluster of compute nodes may have host bundle libraries which are specific to the particular compute node. In embodiments, the host bundle library indicates a set of application bundle sharing states which map to the cluster of compute nodes at block  725 . For instance, the host bundle library on the first compute node can indicate/signal/denote/track that a particular compute node of the cluster shares one or more application bundles. 
     The host bundle library may be maintained at a host level. When a host (e.g., particular compute node) is started-up, it can register/identify its usage of the bundle library by placing/inserting a file/object/identifer with a matching host name/identifier into a sharing hosts section (of the host bundle library). The application bundle itself (e.g., application bundle image) can be placed into a library section. As one or more hosts register their usage (e.g., by writing a file which can be identified/named the same as the host) any/other hosts can see which hosts they are sharing the bundle library with. 
     At block  730 , a stream of tuples is received. The stream of tuples is to be processed by a plurality of processing elements operating on the cluster of compute nodes including the first compute node. The stream of tuples may be received consistent with the description herein including  FIGS. 1-6 . Current/future processing by the plurality of processing elements may be performed consistent with the description herein including  FIGS. 1-6 . The set of compute nodes may include a shared pool of configurable computing resources. For example, the set of compute nodes can be a public cloud environment, a private cloud environment, or a hybrid cloud environment. In certain embodiments, each of the set of compute nodes are physically separate from one another. 
     At block  740 , the cluster bundle directory is used to detect that the application bundle is not installed on the first compute node. For instance, the cluster bundle directory can be searched for compute nodes having the application bundle. In embodiments, a request may be sent to a bundle controller associated with the cluster bundle directory. If the search fails to return the first compute node as a result, then it may be sensed that the application bundle is not installed on the first compute node. Various methodologies for reading the cluster bundle directory may be used. Also, publish-subscribe or push-pull models are considered with respect to collecting information from the cluster bundle directory. For example, when a processing element is to be started on a specific host, it can detect whether the application bundle is available with respect to the specific host (e.g., check cluster bundle directory to see if the application bundle is installed on the specific host). In such example, if the application bundle is installed it may be used and the methodology may exit; if the application bundle is not installed the methodology may continue. 
     At block  750 , both the cluster bundle directory and the host bundle library are used to determine to initiate a sourcing operation with respect to the application bundle. For instances when the application bundle is not installed on the first compute node, sharing host(s) may be retrieved from the host bundle library (e.g., extracting sharing host data from a repository). Also, the cluster bundle directory may be examined/checked to ascertain if the application bundle is installed on at least one of the sharing hosts (e.g., query a database for the sharing hosts with respect to the application bundle). 
     If the application bundle is installed on at least one of the sharing hosts, then an installation on the first compute node may be absent from the sourcing operation. The sourcing operation can include accessing/using the application bundle on a particular host which shares the application bundle. Shared storage associated with the particular host/application bundle may be analyzed/checked. The analysis can identify whether any file system latency exists or has been resolved (e.g., by using file system locking mechanisms). 
     If the application bundle is not installed on any sharing hosts, then the sourcing operation may include the application bundle may be downloaded from one of the locations noted the cluster bundle directory to the appropriate place in the host bundle library. In response to initiating the sourcing operation, the cluster bundle directory may be updated at block  755 . Updating can include adding/modifying an entry for the particular host and application bundle with respect to the cluster bundle directory (e.g., regardless of whether the application bundle was installed on at least one of the sharing hosts). 
     In embodiments, determining, using both the cluster bundle directory and the host bundle library, to initiate the sourcing operation with respect to the application bundle can include a first set of determinations. A first determination of the first set of determinations may be made to install the application bundle on the first compute node at block  751  (e.g., analysis indicates installation of the application bundle outweighs feasibility of using the application bundle from a shared computing environment). A second determination of the first set of determinations may be made to download the application bundle from a second compute node based on the cluster bundle directory at block  752  (e.g., analysis of the cluster bundle directory indicates download from the second compute node is possible and may be efficient with respect to performance relative to other possible download sources). 
     Accordingly, the sourcing operation can include a first set of components. A first component of the first set of components can include downloading the application bundle from a second compute node at block  753  (e.g., transmitting a request for the application bundle and receiving the application bundle in response to the request). A second component of the first set of components may include installing the application bundle on the first compute node at block  754  (e.g., initiating deployment of the application bundle on the first compute node to be executed when processing the stream of tuples). 
     In embodiments, determining, using both the cluster bundle directory and the host bundle library, to initiate the sourcing operation with respect to the application bundle can include a second set of determinations. A first determination of the second set of determinations may determine/identify/resolve/ascertain an application bundle sharing state at block  756  (e.g., an indication that at least one application bundle is shared by a specific host by may be indicated by a first value, and an indication that at least one application bundle is not shared may be indicated by a second value which may include a lack of an entry). The first determination of the second set of determinations may be based on the host bundle library (e.g., the host bundle library may be analyzed with respect to the first/second values). The application bundle sharing state can map to the second compute node. A second determination of the second set of determinations may determine that the second compute node shares the application bundle at block  757  (e.g., the second compute node can be shared-from in order to run the application bundle on another compute node such as the first compute node). The second determination of the second set of determinations may be based on the cluster bundle directory (e.g., the cluster bundle directory may indicate the second compute node has the application bundle). 
     Accordingly, the sourcing operation can include a second set of components. A first component of the second set of components can include analyzing a latency element (e.g., a temporal period related to installation/runtime/removal with respect to data transfer speed/bandwidth/performance/efficiency that may be predicted/current/historical) associated with a second compute node and comparing the latency element with a threshold latency (e.g., a tolerated temporal period for data transfer which may be historically-based or user-defined) at block  758 . A second component of the second set of components can include accessing the application bundle on the second compute node at block  759  (e.g., reading shared data, providing inputs and gathering outputs, configuring to process the stream of tuples using the application bundle on the second compute node). The second component of the second set of components may be performed in response to the threshold latency exceeding the latency element (e.g., bandwidth is acceptable for using sharing via the application bundle on the second compute node). The application bundle may be accessed without downloading the application bundle from the second compute node and without installing the application bundle on the first compute node (e.g., the application bundle is physically absent from the first compute node). In certain embodiments, sharing may initially be indicated but the latency element may have such a predicted impact on performance/efficiency such that downloading the application bundle is determined to be appropriate. 
     At block  760 , in response to initiating the sourcing operation, the stream of tuples is processed using the application bundle. The stream of tuples may be processed consistent with the description herein including  FIGS. 1-6 . In various embodiments, a set of operations may occur in response to processing the stream of tuples using the application bundle. In embodiments, based on both the cluster bundle directory and the host bundle library, a triggering event may be detected at block  770 . The triggering event can occur when a last/final processing element of a last/final job that uses a particular application bundle on a particular host gets canceled or is no longer utilized/needed. In response to detecting the triggering event, it may be determined to remove the application bundle at block  780 . 
     The detection/determination can include checking to resolve whether the application bundle may be uninstalled from the host bundle library (e.g., get sharing hosts from host bundle library). The detection/determination may include checking the cluster bundle directory to identify entries that exist for any/other of the sharing hosts (e.g., ascertain if the only host entry is for itself). For instance, if a particular compute node ascertains that the only host entry is for itself, then it may be resolved that the application bundle (e.g., and associated data) may be uninstalled/removed/deleted from the host bundle library. In response to determining to remove the application bundle, the application bundle can be removed at block  790 . Removing the application bundle can include editing the cluster bundle directory to remove/delete the particular host-bundle entry. 
     Method  700  concludes at block  799 . Aspects of method  700  may provide performance or efficiency benefits for processing a stream of tuples using an application bundle. For example, aspects of method  700  may include positive impacts on resource usage with respect to maintenance operations or responsiveness with respect to various communications. Altogether, performance or efficiency benefits when managing application bundle(s) may occur (e.g., speed, flexibility, responsiveness, resource usage). 
     In addition to embodiments described above, other embodiments having fewer operational steps, more operational steps, or different operational steps are contemplated. Also, some embodiments may perform some or all of the above operational steps in a different order. The modules are listed and described illustratively according to an embodiment and are not meant to indicate necessity of a particular module or exclusivity of other potential modules (or functions/purposes as applied to a specific module). 
     In the foregoing, reference is made to various embodiments. It should be understood, however, that this disclosure is not limited to the specifically described embodiments. Instead, any combination of the described features and elements, whether related to different embodiments or not, is contemplated to implement and practice this disclosure. Many modifications and variations may be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. Furthermore, although embodiments of this disclosure may achieve advantages over other possible solutions or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of this disclosure. Thus, the described aspects, features, embodiments, and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). 
     The present invention may be a system, a method, and/or a computer program product. The computer program product may include a computer readable storage medium (or media) having computer readable program instructions thereon for causing a processor to carry out aspects of the present invention. 
     The computer readable storage medium can be a tangible device that can retain and store instructions for use by an instruction execution device. The computer readable storage medium may be, for example, but is not limited to, an electronic storage device, a magnetic storage device, an optical storage device, an electromagnetic storage device, a semiconductor storage device, or any suitable combination of the foregoing. A non-exhaustive list of more specific examples of the computer readable storage medium includes the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a static random access memory (SRAM), a portable compact disc read-only memory (CD-ROM), a digital versatile disk (DVD), a memory stick, a floppy disk, a mechanically encoded device such as punch-cards or raised structures in a groove having instructions recorded thereon, and any suitable combination of the foregoing. A computer readable storage medium, as used herein, is not to be construed as being transitory signals per se, such as radio waves or other freely propagating electromagnetic waves, electromagnetic waves propagating through a waveguide or other transmission media (e.g., light pulses passing through a fiber-optic cable), or electrical signals transmitted through a wire. 
     Computer readable program instructions described herein can be downloaded to respective computing/processing devices from a computer readable storage medium or to an external computer or external storage device via a network, for example, the Internet, a local area network, a wide area network and/or a wireless network. The network may comprise copper transmission cables, optical transmission fibers, wireless transmission, routers, firewalls, switches, gateway computers and/or edge servers. A network adapter card or network interface in each computing/processing device receives computer readable program instructions from the network and forwards the computer readable program instructions for storage in a computer readable storage medium within the respective computing/processing device. 
     Computer readable program instructions for carrying out operations of the present invention may be assembler instructions, instruction-set-architecture (ISA) instructions, machine instructions, machine dependent instructions, microcode, firmware instructions, state-setting data, or either source code or object code written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like, and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The computer readable program instructions may execute entirely on the user&#39;s computer, partly on the user&#39;s computer, as a stand-alone software package, partly on the user&#39;s computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user&#39;s computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer (for example, through the Internet using an Internet Service Provider). In some embodiments, electronic circuitry including, for example, programmable logic circuitry, field-programmable gate arrays (FPGA), or programmable logic arrays (PLA) may execute the computer readable program instructions by utilizing state information of the computer readable program instructions to personalize the electronic circuitry, in order to perform aspects of the present invention. 
     Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer readable program instructions. 
     These computer readable program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. These computer readable program instructions may also be stored in a computer readable storage medium that can direct a computer, a programmable data processing apparatus, and/or other devices to function in a particular manner, such that the computer readable storage medium having instructions stored therein comprises an article of manufacture including instructions which implement aspects of the function/act specified in the flowchart and/or block diagram block or blocks. 
     The computer readable program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other device to cause a series of operational steps to be performed on the computer, other programmable apparatus or other device to produce a computer implemented process, such that the instructions which execute on the computer, other programmable apparatus, or other device implement the functions/acts specified in the flowchart and/or block diagram block or blocks. 
     Embodiments according to this disclosure may be provided to end-users through a cloud-computing infrastructure. Cloud computing generally refers to the provision of scalable computing resources as a service over a network. More formally, cloud computing may be defined as a computing capability that provides an abstraction between the computing resource and its underlying technical architecture (e.g., servers, storage, networks), enabling convenient, on-demand network access to a shared pool of configurable computing resources that can be rapidly provisioned and released with minimal management effort or service provider interaction. Thus, cloud computing allows a user to access virtual computing resources (e.g., storage, data, applications, and even complete virtualized computing systems) in “the cloud,” without regard for the underlying physical systems (or locations of those systems) used to provide the computing resources. 
     Typically, cloud-computing resources are provided to a user on a pay-per-use basis, where users are charged only for the computing resources actually used (e.g., an amount of storage space used by a user or a number of virtualized systems instantiated by the user). A user can access any of the resources that reside in the cloud at any time, and from anywhere across the Internet. In context of the present disclosure, a user may access applications or related data available in the cloud. For example, the nodes used to create a stream computing application may be virtual machines hosted by a cloud service provider. Doing so allows a user to access this information from any computing system attached to a network connected to the cloud (e.g., the Internet). 
     Embodiments of the present disclosure may also be delivered as part of a service engagement with a client corporation, nonprofit organization, government entity, internal organizational structure, or the like. These embodiments may include configuring a computer system to perform, and deploying software, hardware, and web services that implement, some or all of the methods described herein. These embodiments may also include analyzing the client&#39;s operations, creating recommendations responsive to the analysis, building systems that implement portions of the recommendations, integrating the systems into existing processes and infrastructure, metering use of the systems, allocating expenses to users of the systems, and billing for use of the systems. 
     The flowchart and block diagrams in the Figures illustrate the architecture, functionality, and operation of possible implementations of systems, methods, and computer program products according to various embodiments of the present invention. In this regard, each block in the flowchart or block diagrams may represent a module, segment, or portion of instructions, which comprises one or more executable instructions for implementing the specified logical function(s). In some alternative implementations, the functions noted in the block may occur out of the order noted in the figures. For example, two blocks shown in succession may, in fact, be executed substantially concurrently, or the blocks may sometimes be executed in the reverse order, depending upon the functionality involved. It will also be noted that each block of the block diagrams and/or flowchart illustration, and combinations of blocks in the block diagrams and/or flowchart illustration, can be implemented by special purpose hardware-based systems that perform the specified functions or acts or carry out combinations of special purpose hardware and computer instructions. 
     While the foregoing is directed to exemplary embodiments, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow. The descriptions of the various embodiments of the present disclosure have been presented for purposes of illustration, but are not intended to be exhaustive or limited to the embodiments disclosed. Many modifications and variations will be apparent to those of ordinary skill in the art without departing from the scope and spirit of the described embodiments. The terminology used herein was chosen to explain the principles of the embodiments, the practical application or technical improvement over technologies found in the marketplace, or to enable others of ordinary skill in the art to understand the embodiments disclosed herein.