Abstract:
Provided are techniques for providing a virtual machine (VM) workload partition (WPAR) with an versioned operating system (OS) that is different than a native OS associated with a logical partition (LPAR) corresponding to the WPAR, wherein the versioned OS is an earlier version of the native OS; detecting an executable file associated with the versioned OS that has been designated to be overlaid with a corresponding executable from the native OS; generating a link to the corresponding executable; and installing the link in the WPAR rather than the executable file.

Description:
FIELD OF DISCLOSURE 
       [0001]    The claimed subject matter relates generally to computing systems and, more specifically, to techniques for providing a virtual file space access to files that are not installed within the space. 
       BACKGROUND OF THE INVENTION 
       [0002]    Unlike logical partitions (LPARs), in which computing resources are partitioned with respect to hardware, a virtualized file system is partitioned with respect to software. In addition, unlike LPARs which may have different operating systems, virtualized file system spaces include virtualized operating system (OS) environments within a single instance of an OS. One example of a virtualized file system space, used as an example throughout this Specification, is a workload partition (WPAR). It should be understood that although the claimed subject matter is described with respect to WPARs, the same principles also apply to other types of virtualized file system spaces. 
         [0003]    Basically, there are two types of WPARs, system WPARs and application WPARs. Typically, a system WPAR partitions system resources and an application WPAR isolates and executes one or more application processes. The following description is based upon system WPARs. Each WPAR has a regulated share of system resources and may have unique networks and file systems. In addition, each WPAR may have separate administrative and security domains, with each WPAR having a unique root user, regular users and passwords, its own services such as inetd, cron and syslog, and can be stopped and started on its own. A WPAR does not typically share writable file systems with other WPARs or the global system. WPARs share an operating system and may share underlying file systems, real or virtual disk adapters, processors, memory, paging space and a real or virtual network card. 
         [0004]    Although WPARs within a particular LPAR share one OS, different WPARs within a LPAR may run different versions of a particular OS. Such a WPAR is called a “versioned” WPAR. A versioned WPAR typically runs an older version of an OS than the global, or “native,” LPAR. The versioned WPAR contains commands, shared libraries, and so on of whatever level of OS it is running. However some commands, such as, but not limited to, device drivers and other kernel extensions, within a versioned WPAR are “overlaid,” which means that the WPAR runs the corresponding command in the global LPAR. Typically, this is necessary to keep certain commands in sync with the kernel on the global LPAR because WPARs do not include their own kernel. 
         [0005]    When a file is overlaid in the WPAR, the file is renamed, typically by adding a suffix to the name and a symbolic link to a copy of the native runtime execution wrapper is created with the name of the original file, or legacy binary. Typically, there is one copy of the native execution wrapper for each target binary&#39;s directory path. In addition, actions are taken to reflect these changes in administrative files that an install facility uses to track the state of all installed files on the system by replacing references to the original name with the new name with the added suffix. The wrapper mechanism typically works as follows: 1) The path of the native library is pre-pended to the LIBPATH parameter; 2) The name of the executable that invoked the wrapper is identified; and 3) A special new “native runtime exec( ) interface” is called to execute the corresponding native binary. 
       SUMMARY 
       [0006]    As the Inventors herein have realized, the overlay mechanism described above assumes there is a file installed in the WPAR that is to be overlaid. Typically, there are base filesets explicitly installed in versioned WPARs and all the files are overlaid so that the latest version of those files present in the global LPAR are executed. In this situation, there may be executables from these filesets that are installed in the WPAR but never executed. In addition, these techniques tie the service stream for the versioned WPAR product to the OS support process. Every time there is an update to one of those base filesets, a repackaging of the versioned WPAR product filesets is triggered. 
         [0007]    Provided are techniques for providing a virtual machine (VM) workload partition (WPAR) with an versioned operating system (OS) that is different than a native OS associated with a logical partition (LPAR) corresponding to the WPAR, wherein the versioned OS is an earlier version of the native OS; detecting an executable file associated with the versioned OS that has been designated to be overlaid with a corresponding executable from the native OS; generating a link to the corresponding executable; and installing the link in the WPAR rather than the executable file. 
         [0008]    This summary is not intended as a comprehensive description of the claimed subject matter but, rather, is intended to provide a brief overview of some of the functionality associated therewith. Other systems, methods, functionality, features and advantages of the claimed subject matter will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0009]    A better understanding of the claimed subject matter can be obtained when the following detailed description of the disclosed embodiments is considered in conjunction with the following figures, in which: 
           [0010]      FIG. 1  is a block diagram of a computing system architecture that may implement the claimed subject matter. 
           [0011]      FIG. 2  is a block diagram of a workload partition (WPAR) Overlay Manager (OM), introduced above in  FIG. 1 , in greater detail. 
           [0012]      FIG. 3  is a flowchart of one example of a Create WPAR process that may implement aspects of the claimed subject matter. 
           [0013]      FIG. 4  is a flowchart of one example of a Fileset (FS) Overlay process that may implement aspects of the claimed subject matter. 
       
    
    
     DETAILED DESCRIPTION 
       [0014]    As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as a “circuit,” “module” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon. 
         [0015]    Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the computer readable storage medium would include the following: an electrical connection having one or more wires, 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), an optical fiber, a portable compact disc read-only memory (CD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain, or store a program for use by or in connection with an instruction execution system, apparatus, or device. 
         [0016]    A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device. 
         [0017]    Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fiber cable, RF, etc. or any suitable combination of the foregoing. 
         [0018]    Computer program code for carrying out operations for aspects of the present invention may be 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 program code 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). 
         [0019]    Aspects of the present invention are described below 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 program instructions. These computer 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. 
         [0020]    These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks. 
         [0021]    The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational actions to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks. It should also be understood that, although described with respect to WPARs, the claimed subject matter is equally applicable to other types of virtualized file system spaces. 
         [0022]    Turning now to the figures,  FIG. 1  is a block diagram of one example of a computing system architecture  100  that may incorporate the claimed subject matter. A computing system  102  includes a central processing unit (CPU)  104 , coupled to a monitor  106 , a keyboard  108  and a pointing device, or “mouse,”  110 , which together facilitate human interaction with the elements of computing system  100  and client system  102 . Also included in client system  102  and attached to CPU  104  are computer-readable storage mediums (CRSMs), specifically a CRSM — 1  111 , a CRSM — 2  112  and a CRSM — 3  113 . Each of CRSMs  111 - 113  may either be incorporated into client system  102 , i.e. an internal device, or attached externally to CPU  104  by means of various, commonly available connection devices such as but not limited to, a universal serial bus (USB) port (not shown). 
         [0023]    CRSM — 1  111  is illustrated storing a logical partition (LPAR)  114 , which includes an operating system (OS)  116 , a shared memory  118 , a WPAR Overlay Manager (OLM)  120  and a number of workload partitions (WPARs), i.e. a WPAR — 1  121 , a WPAR — 2  122  and a WPAR — 3  123 . In the following examples, WPAR OLM  120  is configured to implement the claimed subject matter. In addition, WPAR — 1  121  is a versioned WPAR, i.e., running a less current version of OS  116  than LPAR  114 . In conjunction with the versioning of WPAR — 1  121 , WPAR — 1  121  includes overlaid filesets (OFS), i.e. an OFS  126 . In this example, WPAR — 2  122  and WPAR — 3  123  are native WPARs, i.e. running the same version of OS  116  as LPAR  114 . The implementation and maintenance of WPAR  121  is explained in more detail below in conjunction with  FIGS. 2-4 . 
         [0024]    Computing system  102  is also coupled to the Internet  130 , which is in turn coupled to two (2) other computing systems, i.e. a client  132  and a server  134 . Although in this example, computing system  102  and computing systems  132  and  134  are communicatively coupled via the Internet  130 , they could also be coupled through any number of communication mediums such as, but not limited to, a local area network (LAN) (not shown). Computing devices  132  and  134  are used as examples of resources that may be available to computing system  102  and serve as potential access points to computing system  102 . It should be noted that a typical computing system would typically include many addition elements, but for the sake of simplicity only a few are shown. 
         [0025]      FIG. 2  is a block diagram of WPAR OLM  120 , introduced above in  FIG. 1 , in greater detail. WPAR OLM  120  includes an input/output (I/O) module  140 , a data module  142 , an overlay module  144  and operation logic  146 . Although there may be other components of WPAR OLM  120 , for the sake of simplicity, only components  140 ,  142 ,  144  and  146  are illustrated and described. For the sake of the following examples, logic associated with WPAR OLM  120  is assumed to execute on one or more processors (not shown) of computing system  102  ( FIG. 1 ) and to be stored on CRSM — 1  111  ( FIG. 1 ). It should be understood that the claimed subject matter can be implemented in many types of computing systems and data storage structures but, for the sake of simplicity, is described only in terms of computing system  102  and system architecture  100  ( FIG. 1 ). Further, the representation of WPAR OLM  120  in  FIG. 2  is a logical model. In other words, components  140 ,  142 ,  144  and  146  may be stored in the same or separates files and loaded and/or executed within computing system  102  and architecture  100  either as a single system or as separate processes interacting via any available inter process communication (IPC) techniques. 
         [0026]    I/O module  140  handles any communication WPAR OLM  1240  has with other components of computing system  102  and architecture  100 . Data module  142  is a data repository for information and parameters that WPAR OLM  120  requires during operation. Examples of the types of information stored in data module  142  include WPAR data  152 . version data  154 , fileset data  156  and option data  158 . 
         [0027]    WPAR data  152  stores information relating to established WPARs such as WPARs  121 - 123 , including, but not limited to, various resources that may be allocated to each of WPARs  121 - 123  and whether or not the WPAR is a versioned or native WPAR. Version data  154  stores information on the specific version of OS  116  that each WPAR  121 - 123  is currently executing. Fileset data  156  stores information about the filesets installed in each of WPARs  121 - 123  as well as the specific filesets that have been overlaid in accordance with the claimed subject matter. Option data  158  stores user and administrative operating parameters that may control the operation of WPAR OLM  120 . 
         [0028]    Overlay module  144  stores logic responsible for installing the appropriate filesets in versioned WPARs such as WPAR  121  in accordance with the claimed subject matter. Operation logic  148  stores logic associated with implementation of the claimed subject matter as well as logic responsible for the typical logic associated with the installation and updating of WPARs such as WPARs  121 - 123 . Components  142 ,  144 ,  146 ,  152 ,  154 ,  156  and  158  are described in more detail below in conjunction with  FIGS. 3-4 . 
         [0029]      FIG. 3  is a flowchart of one example of a Create WPAR process  200  that may implement aspects of the claimed subject matter. In this example, process  200  is associated with logic stored on CRSM — 1  111  ( FIG. 1 ) in conjunction with WPAR OLM  120  ( FIG. 1 ) and executed on one or more processors (not shown) of CPU  104  ( FIG. 1 ) of computing system  102  ( FIG. 1 ). 
         [0030]    Process  200  begins in a “Begin Create WPAR” block  202  and proceeds immediately to a “Receive Request”block  204 . During processing associated with block  204 , a request to generate a new WPAR is received at WPAR OLM  120  ( FIGS. 1 and 2 ). During processing associated with a “Generate WPAR” block  206 , procedures that are familiar to those with skill in the relevant arts allocate and populate memory and update relevant files associated with the new WPAR are implemented. 
         [0031]    During processing associated with a “Native WPAR?” block, a determination is made as to whether or not the WPAR requested during processing associated with block  204  and generated during processing associated with block  206  is native, i.e., configured to run the current version of OS  116 , or non-native, i.e., configured to run an older version of OS  116 . If non-native, control proceeds to a “Retrieve Overlay List” block  210 . During processing associated with block  210 , information that specifies those files and their corresponding filesets within the WPAR that need to be overlaid with current files corresponding to the current OS (see  154  and  156 ,  FIG. 2 ) is retrieved. 
         [0032]    During processing associated with a “Get Next File” block  212 , the next file listed in the information retrieved during processing associated with block  210  is selected for processing. Of course, the during the first iteration through block  212 , this would typically be the first file in the list. During processing associated with a “Generate Overlay” block  214 , the file selected for processing during processing associated with block  212  is processed (see  250 ,  FIG. 4 ). During processing associated with a “More Files?” block  216 , a determination is made as to whether or not there are additional, unprocessed files listed in the information retrieved during processing associated with block  210 . If so, control returns to block  212 , the next file is selected for processing and processing continues as described above. 
         [0033]    Finally, if during processing associated with block  216  a determination is made as that there are no more files to process or, if during processing associated with block  208 , a determination is made that the WPAR being created is native, control proceeds to an “End Create WPAR” block  219  in which process  200  is complete. 
         [0034]      FIG. 4  is a flowchart of one example of a Generate Overlay process  250  that may implement aspects of the claimed subject matter. Process  250  corresponds to Generate Overlay block  214  ( FIG. 3 ) of Create WPAR process  200  ( FIG. 3 ). Like process  200 , in this example, process  250  is associated with logic stored on CRSM — 1  111  ( FIG. 1 ) in conjunction with WPAR OLM  120  ( FIG. 1 ) and executed on one or more processors (not shown) of CPU  104  ( FIG. 1 ) of computing system  102  ( FIG. 1 ). 
         [0035]    Process  250  begins in a “Begin Generate Overlay” block  252  and proceeds immediately to a “Fileset (FS) Present?” block  254 . During processing associated with block  254 , a determination is made as to whether or not the file being processed (see  212 ,  FIG. 3 ) is a member of a filesset that is already present in the WPAR being generated (see  206 ,  FIG. 3 ). As explained above, information on the files of the WPAR (see  154  and  156 ,  FIGS. 2 and 210 ,  FIG. 3 ) includes the fileset to which the file belongs. It should also be noted that, although not illustrated in this particular diagram, if a particular file is not present and not part of a mandatory fileset, the file is not needed and therefore no overlay is created. 
         [0036]    If the fileset is present, control proceeds to a “Save Original File” block  256 . During processing associated with block  256 , the file that is already installed is renamed, typically by adding a suffix to the original name. In addition, references to the file in any files that track the file for administrative purposes are also modified to reflect the new name so that, when the original file is to be updated, the original file is updated rather than the file identified by the link. If, during processing associated with block  254  a determination is made that the fileset to which the file belongs is not present, control proceeds to an “FS Mandatory?” block  258 . During processing associated with block  258 , a determination is made as to whether or not the fileset that was determined not to be present during processing associated with block  254  is a required fileset. If so, or if during processing associated with block  256  the original file has been saved under a new name, control proceeds to a “File Binary?” block  260 . During processing associated with block  260 , a determination is made as to whether or not the file being processed is binary or not, i.e. a script file. If the file is binary, control proceeds to a “Create Link to Runtime Execution Wrapper (RTEW)” block  262 . During processing associated with block  262 , a link to the RTEW is generated, having the original name of the file. If a determination is made, during processing associated with block  260 , that the file being processed in not binary, then control proceeds to “Create Link to Global Script File (GSF)?” block  264 . During processing associated with block  264 , a link is created to the corresponding global script file. It should be noted that a script file does not need to employ a RTEW so the link points directly to the corresponding GSF of the native OS. 
         [0037]    In addition, if a determination was made during processing associated with block  254 , that the file was not present and during processing associated with block  258  that the file was mandatory, then the original file did not need to be renamed because the file was not in memory. In this manner, files that do not need to be installed and will never be used are not installed and do not consume computing resources. 
         [0038]    Once a either link to a RTEW has been created during processing associated with block  262  or a link to a GSF created during block  264 , control proceeds to an “End Generate Overlay” block  279  during which process  250  is complete. Files handled in accordance with the disclosed technology eliminate work the WPAR OLM  120  would typically need to perform because original files are not installed and thus do not need to be overlaid during updates. Concerns that overlaid files are over-written are also eliminated. In addition, any updates to files in the global LPAR  114  are automatically applied because the WPAR  121  will point to the updated binaries and scripts as soon as they are placed in the LPAR  121 . 
         [0039]    The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
         [0040]    The corresponding structures, materials, acts, and equivalents of all means or step plus function elements in the claims below are intended to include any structure, material, or act for performing the function in combination with other claimed elements as specifically claimed. The description of the present invention has been presented for purposes of illustration and description, but is not intended to be exhaustive or limited to the invention in the form 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 invention. The embodiment was chosen and described in order to best explain the principles of the invention and the practical application, and to enable others of ordinary skill in the art to understand the invention for various embodiments with various modifications as are suited to the particular use contemplated. 
         [0041]    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 code, which comprises one or more executable instructions for implementing the specified logical function(s). It should also be noted that, 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 combinations of special purpose hardware and computer instructions.