InfoScale™ 9.0 Cluster Server Agent Developer's Guide - AIX, Linux, Solaris, Windows

Last Published:
Product(s): InfoScale & Storage Foundation (9.0)
Platform: AIX,Linux,Solaris,Windows
  1. Introduction
    1.  
      About VCS agents
    2. How agents work
      1.  
        About the agent framework
      2.  
        About intelligent monitoring framework (IMF)
      3.  
        Resource type definitions
      4.  
        About agent functions (entry points)
      5.  
        About on-off, on-only, and persistent resources
      6. About attributes
        1.  
          Attribute data types
        2.  
          Attribute dimensions
        3.  
          Attribute scope across systems: global and local attributes
        4.  
          Attribute life: temporary attributes
      7.  
        About intentional offline of applications
    3. About developing an agent
      1.  
        Considerations for the application
      2. High-level overview of the agent development process
        1.  
          Creating the type definition file
        2.  
          Developing the entry points
        3.  
          Building the agent
        4.  
          Testing the agent
  2. Agent entry point overview
    1. About agent entry points
      1.  
        Supported entry points
      2.  
        How the agent framework interacts with entry points
    2. Agent entry points described
      1.  
        About the open entry point
      2.  
        About the monitor entry point
      3.  
        About the online entry point
      4.  
        About the offline entry point
      5.  
        About the clean entry point
      6. About the action entry point
        1.  
          Return values for action entry point
      7. About the info entry point
        1.  
          Return values for info entry point
        2.  
          About the ResourceInfo attribute
        3.  
          Invoking the info entry point
      8.  
        About the attr_changed entry point
      9.  
        About the close entry point
      10.  
        About the shutdown entry point
      11.  
        About the imf_init entry point
      12.  
        About the imf_register entry point
      13.  
        About the imf_getnotification entry point
      14.  
        About the migrate entry point
      15.  
        About the meter entry point
    3.  
      Return values for entry points
    4. Considerations for using C++ or script entry points
      1. About the VCSAgStartup routine
        1.  
          If you implement entry points using scripts
        2.  
          If you implement all or some of the entry points in C++
        3.  
          Example: VCSAgStartup with C++ and script entry points
    5. About the agent information file
      1. Example agent information file (UNIX)
        1.  
          Agent information
        2.  
          Attribute argument details
      2.  
        Implementing the agent XML information file
    6. About the ArgList and ArgListValues attributes
      1.  
        ArgListValues attribute for agents registered as V50 and later
      2. Overview of the name-value tuple format
        1.  
          Scalar attribute format
        2.  
          Vector attribute format
        3.  
          Keylist attribute format
        4.  
          Association attribute format
      3.  
        ArgListValues attribute for different agents versions
      4.  
        About the entry point timeouts
  3. Creating entry points in C++
    1. About creating entry points in C++
      1.  
        Entry point examples in this chapter
    2.  
      Data Structures
    3. Syntax for C++ entry points
      1.  
        Syntax for C++ VCSAgStartup
      2.  
        Syntax for C++ monitor
      3. Syntax for C++ info
        1.  
          resinfo_op
        2.  
          info_output
        3.  
          opt_update_args
        4.  
          opt_add_args
        5.  
          Example: info entry point implementation in C++
      4.  
        Syntax for C++ online
      5.  
        Syntax for C++ offline
      6.  
        Syntax for C++ clean
      7.  
        Syntax for C++ action
      8.  
        Syntax for C++ attr_changed
      9.  
        Syntax for C++ open
      10.  
        Syntax for C++ close
      11.  
        Syntax for C++ shutdown
      12.  
        Syntax for C++ migrate
      13.  
        Syntax for C++ meter
    4. Agent framework primitives
      1.  
        VCSAgGetMonitorLevel
      2.  
        VCSAgGetFwVersion
      3.  
        VCSAgGetRegVersion
      4.  
        VCSAgRegisterEPStruct
      5.  
        VCSAgSetCookie2
      6.  
        VCSAgRegister
      7.  
        VCSAgUnregister
      8.  
        VCSAgGetCookie
      9.  
        VCSAgStrlcpy
      10.  
        VCSAgStrlcat
      11.  
        VCSAgSnprintf
      12.  
        VCSAgCloseFile
      13.  
        VCSAgDelString
      14.  
        VCSAgExec
      15.  
        VCSAgExecWithTimeout
      16.  
        VCSAgGenSnmpTrap
      17.  
        VCSAgSendTrap
      18.  
        VCSAgLockFile
      19.  
        VCSAgInitEntryPointStruct
      20.  
        VCSAgSetStackSize
      21.  
        VCSAgUnlockFile
      22.  
        VCSAgValidateAndSetEntryPoint
      23.  
        VCSAgSetLogCategory
      24.  
        VCSAgGetProductName
      25.  
        VCSAgMonitorReturn
      26.  
        VCSAgSetResEPTimeout
      27.  
        VCSAgDecryptKey
      28.  
        VCSAgGetConfDir
      29.  
        VCSAgGetHomeDir
      30.  
        VCSAgGetLogDir
      31.  
        VCSAgGetSystemName
      32.  
        VCSAG_CONSOLE_LOG_MSG
      33.  
        VCSAG_LOG_MSG
      34.  
        VCSAG_LOGDBG_MSG
      35.  
        VCSAG_RES_LOG_MSG
    5. Agent Framework primitives for container support
      1.  
        VCSAgIsContainerUp
      2.  
        VCSAgGetContainerTypeEnum
      3.  
        VCSAgExecInContainer2
      4.  
        VCSAgIsContainerCapable
      5.  
        VCSAgExecInContainerWithTimeout
      6.  
        VCSAgGetUID
      7.  
        VCSAgIsPidInContainer
      8.  
        VCSAgIsProcInContainer
      9.  
        VCSAgGetContainerID2
      10.  
        VCSAgGetContainerName2
      11.  
        VCSAgGetContainerBasePath
      12.  
        VCSAgGetContainerEnabled
  4. Creating entry points in scripts
    1. About creating entry points in scripts
      1. Rules for using script entry points
        1.  
          On UNIX platforms
      2.  
        Parameters and values for script entry points
      3.  
        ArgList attributes
      4.  
        Examples
    2. Syntax for script entry points
      1.  
        Syntax for the monitor script
      2.  
        Syntax for the online script
      3.  
        Syntax for the offline script
      4.  
        Syntax for the clean script
      5.  
        Syntax for the action script
      6.  
        Syntax for the attr_changed script
      7.  
        Syntax for the info script
      8.  
        Syntax for the open script
      9.  
        Syntax for the close script
      10.  
        Syntax for the shutdown script
      11.  
        Syntax for the imf_init script
      12.  
        Syntax for the imf_register script
      13.  
        Syntax for the imf_getnotification script
      14.  
        Syntax for migrate script
      15.  
        Syntax for meter script
    3. Agent framework primitives
      1.  
        VCSAG_GET_MONITOR_LEVEL
      2.  
        VCSAG_GET_AGFW_VERSION
      3.  
        VCSAG_GET_REG_VERSION
      4.  
        VCSAG_SET_RES_EP_TIMEOUT
      5. VCSAG_GET_ATTR_VALUE
        1.  
          To get number of keys in the key list attribute and the index of attribute in argument list
        2.  
          To get a particular key in the key list and vector attribute
        3.  
          To get the number of keys in the association attribute, and index of attribute in the argument list
        4.  
          To get a particular key or value in the association attribute:
      6.  
        VCSAG_SET_RESINFO
      7.  
        VCSAG_MONITOR_EXIT
      8.  
        VCSAG_SYSTEM
      9.  
        VCSAG_SU
      10.  
        VCSAG_RETURN_IMF_RESID
      11.  
        VCSAG_RETURN_IMF_EVENT
      12.  
        VCSAG_BLD_PSCOMM
      13.  
        VCSAG_PHANTOM_STATE
      14.  
        VCSAG_SET_ENVS
      15.  
        VCSAG_LOG_MSG
      16.  
        VCSAG_LOGDBG_MSG
      17.  
        VCSAG_SQUEEZE_SPACES
    4. Agent Framework primitives with container support
      1.  
        VCSAG_GET_CONTAINER_BASE_PATH
      2.  
        VCSAG_GET_CONTAINER_INFO
      3.  
        VCSAG_IS_PROC_IN_CONTAINER
      4.  
        VCSAG_EXEC_IN_CONTAINER
    5. Example script entry points
      1.  
        Online entry point for FileOnOff
      2.  
        Monitor entry point for FileOnOff
      3.  
        Monitor entry point with intentional offline
      4.  
        Offline entry point for FileOnOff
      5.  
        Monitor entry point for agent having basic (level-1) and detailed (level-2) monitoring
  5. Logging agent messages
    1.  
      About logging agent messages
    2. Logging in C++ and script-based entry points
      1. Agent messages: format
        1.  
          Timestamp
        2.  
          Mnemonic
        3.  
          Severity
        4.  
          UMI
        5.  
          Message text
      2.  
        Log unification of VCS agent's entry points
    3. C++ agent logging APIs
      1.  
        Agent application logging macros for C++ entry points
      2.  
        Agent debug logging macros for C++ entry points
      3.  
        Severity arguments for C++ macros
      4.  
        Initializing function_name using VCSAG_LOG_INIT
      5.  
        Log category
      6.  
        Examples of logging APIs used in a C++ agent
    4. Script entry point logging functions
      1.  
        Using functions in scripts
      2. VCSAG_SET_ENVS
        1.  
          VCSAG_SET_ENVS examples, Shell script entry points
        2.  
          VCSAG_SET_ENVS examples, Perl script entry points
        3.  
          VCSAG_SET_ENVS examples, Python script entry points
      3. VCSAG_LOG_MSG
        1.  
          VCSAG_LOG_MSG examples, Shell script entry points
        2.  
          VCSAG_LOG_MSG examples, Perl script entry points
        3.  
          VCSAG_LOG_MSG examples, Python script entry points
      4. VCSAG_LOGDBG_MSG
        1.  
          VCSAG_LOGDBG_MSG examples, Shell script entry points
        2.  
          VCSAG_LOGDBG_MSG examples, Perl script entry points
        3.  
          VCSAG_LOGDBG_MSG examples, Python script entry points
      5.  
        Example of logging functions used in a script agent
  6. Building a custom agent
    1. Files for use in agent development
      1.  
        Script based agent binaries
      2.  
        C++ based agent binaries
    2. Creating the type definition file for a custom agent
      1.  
        Naming convention for the type definition file
      2.  
        Example: FileOnOffTypes.cf
      3.  
        Example: Type definition for a custom agent that supports intentional offline
      4.  
        Requirements for creating the agentTypes.cf file
      5.  
        Adding the custom type definition to the configuration
    3. Building a custom agent on UNIX
      1.  
        Implementing entry points using scripts
      2.  
        Example: Using script entry points on UNIX
      3.  
        Example: Using VCSAgStartup() and script entry points on UNIX
      4.  
        Implementing entry points using C++
      5.  
        Example: Using C++ entry points on UNIX
      6.  
        Example: Using C++ and script entry points on UNIX
    4.  
      Installing the custom agent
    5. Defining resources for the custom resource type
      1. Sample resource definition
        1.  
          How the FileOnOff agent uses configuration information
    6.  
      Agent framework versions details
  7. Building a script based IMF-aware custom agent
    1.  
      About building a script based IMF-aware custom agent
    2.  
      Linking AMF plugins with script agent
    3. Creating XML file required for AMF plugins to do resource registration for online and offline state monitoring
      1.  
        Example of amfregister.xml for registration of process-based resource with AMF for online monitoring
      2.  
        Example of amfregister.xml for registration of process-based resource with AMF for offline monitoring
      3.  
        Example of amfregister.xml for online and offline IMF monitoring for a given process
      4.  
        Examples for adding RepearName tag in amfregister.xml
    4.  
      Adding IMF and IMFRegList attributes in configuration
    5.  
      Monitor without IMF integration
    6.  
      Monitor without IMF but with LevelTwo monitor frequency
    7.  
      Monitor with IMF integration
    8.  
      Monitor with IMF but with LevelTwo monitor frequency
    9.  
      Installing the IMF-aware script-based custom agent
  8. Testing agents
    1.  
      About testing agents
    2. Using debug messages
      1.  
        Debugging agent functions (entry points).
      2.  
        Debugging the agent framework
    3. Debugging using AdvDbg attribute
      1. Working of AdvDbg attribute
        1.  
          Working of pstack action
        2.  
          Working of core action
      2.  
        Impact of AdvDbg attribute on existing functionality of the entry point
    4. Using the engine process to test agents
      1.  
        Test commands
  9. Static type attributes
    1. About static attributes
      1.  
        Overriding static type attributes
    2. Static type attribute definitions
      1.  
        ActionTimeout
      2. AdvDbg
        1.  
          Configuring AdvDbg attribute and formatting the individual key
        2.  
          Recommended steps for configuring AdvDbg attribute for monitor entry points
      3.  
        AEPTimeout
      4.  
        AgentClass
      5.  
        AgentDirectory
      6.  
        AgentFailedOn
      7.  
        AgentFile
      8.  
        AgentPriority
      9.  
        AgentReplyTimeout
      10.  
        AgentStartTimeout
      11.  
        AlertOnMonitorTimeouts
      12. ArgList
        1.  
          ArgList reference attributes
      13.  
        AttrChangedTimeout
      14.  
        AvailableMeters
      15.  
        CleanRetryLimit
      16.  
        CleanTimeout
      17.  
        CloseTimeout
      18.  
        ContainerOpts
      19.  
        ConfInterval
      20.  
        EPClass
      21.  
        EPPriority
      22.  
        ExternalStateChange
      23.  
        FaultOnMonitorTimeouts
      24.  
        FaultPropagation
      25.  
        FireDrill
      26.  
        IMF
      27.  
        IMFRegList
      28.  
        InfoInterval
      29.  
        InfoTimeout
      30.  
        IntentionalOffline
      31.  
        LevelTwoMonitorFreq
      32.  
        LogDbg
      33.  
        LogFileSize
      34.  
        LogViaHalog
      35.  
        ManageFaults
      36.  
        Meters
      37.  
        MeterControl
      38.  
        MeterRegList
      39.  
        MeterRetryLimit
      40.  
        MeterTimeout
      41.  
        MonitorInterval
      42.  
        MonitorStatsParam
      43.  
        MonitorTimeout
      44.  
        MigrateTimeout
      45.  
        MigrateWaitLimit
      46.  
        NumThreads
      47.  
        OfflineMonitorInterval
      48.  
        OfflineTimeout
      49.  
        OfflineWaitLimit
      50.  
        OnlineClass
      51.  
        OnlinePriority
      52.  
        OnlineRetryLimit
      53.  
        OnlineTimeout
      54.  
        OnlineWaitLimit
      55.  
        OpenTimeout
      56.  
        Operations
      57.  
        RegList
      58.  
        RestartLimit
      59.  
        ScriptClass
      60.  
        ScriptPriority
      61.  
        SourceFile
      62.  
        SupportedActions
      63.  
        SupportedOperations
      64.  
        ToleranceLimit
  10. State transition diagram
    1.  
      State transitions
    2.  
      State transitions with respect to ManageFaults attribute
  11. Internationalized messages
    1.  
      About internationalized messages
    2. Creating SMC files
      1.  
        SMC format
      2.  
        Example SMC file
      3.  
        Formatting SMC files
      4.  
        Naming SMC files, BMC files
      5.  
        Message examples
      6.  
        Using format specifiers
    3. Converting SMC files to BMC files
      1. Storing BMC files
        1.  
          VCS languages
      2.  
        Displaying the contents of BMC files
    4. Using BMC Map Files
      1.  
        Location of BMC Map Files
      2.  
        Creating BMC Map Files
      3.  
        Example BMC Map File
    5.  
      Updating BMC Files
  12. Troubleshooting VCS resource's unexpected behavior using First Failure Data Capture (FFDC)
    1.  
      Enhancing First Failure Data Capture (FFDC) to troubleshoot VCS resource's unexpected behavior
  13. Appendix A. Using pre-5.0 VCS agents
    1. Using pre-5.0 VCS agents and registering them with V50 or later
      1.  
        Outline of steps to change V40 agents to V50 or later
      2.  
        Example script in V40 and V50 or later
      3.  
        Sourcing ag_i18n_inc modules in script entry points
    2.  
      Guidelines for using pre-VCS 4.0 Agents
    3. Log messages in pre-VCS 4.0 agents
      1.  
        Mapping of log tags (pre-VCS 4.0) to log severities (VCS 4.0)
      2.  
        How Pre-VCS 4.0 Messages are Displayed by VCS 4.0 and Later
      3.  
        Comparing Pre-VCS 4.0 APIs and VCS 4.0 Logging Macros
    4. Pre-VCS 4.0 Message APIs
      1.  
        VCSAgLogConsoleMsg
      2.  
        VCSAgLogI18NMsg
      3.  
        VCSAgLogI18NMsgEx
      4.  
        VCSAgLogI18NConsoleMsg
      5.  
        VCSAgLogI18NConsoleMsgEx

Considerations for the application

The application for which an agent for VCS is developed must lend itself to being controlled by the agent and be able to operate in a cluster environment. The following criteria describe an application that can successfully operate in a cluster:

  • The application must be capable of being started by a defined procedure if new agent is of type OnOff or OnOnly. There must be some means of starting the application's external resources such as file systems that store databases, or IP addresses used for listener processes, and so on.

  • Each instance of an application must be capable of being stopped by a defined procedure if new agent is of type OnOff. Other instances of the application must not be affected.

  • The application must be capable of being stopped cleanly, by forcible means if necessary.

  • Each instance of an application must be capable of being monitored uniquely. Monitoring can be simple or in-depth so as to achieve a high level of confidence in the operation of the application. Monitoring an application becomes more effective when the monitoring procedure resembles the actual activity of the application's user.

  • For failover capability, the application must be capable of storing data on shared disks rather than locally or in memory, and each system must be capable of accessing the data and all information required to run the application.

  • The application must be crash-tolerant. It must be capable of being run on a system that crashes and of being started on a failover node in a known state. This typically means that data is regularly written to shared storage rather than stored in memory.

  • The application must be host-independent within a cluster; that is, there are no licensing requirements or host name dependencies that prevent successful failover.

  • The application must run properly with other applications in the cluster.

  • The applications configured under VCS control must not write data on stdout and stderr stream. This may interfere with VCS agent functionality. For such applications to run under VCS control, you must redirect the application's stdout and stderr stream.