Job Management Partner 1/Base User's Guide

3.2 Prerequisites for using JP1/Base in a cluster system and the support range

In a cluster system, JP1 runs in a logical host environment to enable failovers. The prerequisites for executing JP1 in a logical host environment are that clustering software can normally control the assignment and deletion of a shared disk or logical IP address and the monitoring of operations.

Note

Even the clustering software supported by JP1 might not satisfy the prerequisites described below depending on the system configuration and environment settings. You should determine the system configuration and environment settings so that the prerequisites are satisfied.

Organization of this section

(1) Prerequisites for a logical host environment

(2) Prerequisites for a physical host environment

(3) Range supported by JP1

(4) Specifying a logical host

(5) Rules for specifying logical host names

(1) Prerequisites for a logical host environment

When operating JP1 in a logical host environment, you must satisfy the following prerequisites for a logical IP address and shared disk:

Table 3-2 Prerequisites for a logical host environment

Logical host component	Prerequisites
Shared disk	A shared disk must be used that can be taken over from the primary server to the secondary server. The shared disk must be assigned before JP1 is started. The assignment of the shared disk must not be canceled while JP1 is running. The assignment of the shared disk must be canceled after JP1 is stopped. The shared disk must be locked so that multiple servers do not inadvertently use it. Files must be protected using a file system with the journal functionality or other measures so that the files will not be lost due to a system failure. Failovers must guarantee that the contents of all files are taken over correctly. Failovers must be forced to occur even when a process is using the shared disk during failover. Clustering software must be responsible for recovery upon the detection of any failure on the shared disk so that JP1 does not need to perform recovery. Clustering software must issue a start or stop request to JP1 if it is necessary to start or stop JP1 as part of recovery.
Logical IP address	Communication must be performed using a logical IP address that can be taken over. The logical IP address must be uniquely determined from the logical host name. The logical IP address must be assigned before JP1 is started. The logical IP address must not be deleted while JP1 is running. The correspondence between the logical host name and logical IP address must not be modified while JP1 is running. The logical IP address must be deleted after JP1 is stopped. Clustering software must be responsible for recovery upon the detection of a network failure so that JP1 does not need to perform a recovery. Clustering software must issue a start or stop request to JP1 if it is necessary to start or stop JP1 as part of recovery.

If any of the above requirements are not satisfied, JP1 might malfunction. For example:

• If data written from the primary server corrupts upon a failover
  JP1 might encounter a problem, such as an error, lost data, or a failure in starting up.
  
• If no recovery is performed when a LAN board fails
  A communication error occurs, preventing JP1 from operating normally until clustering software switches the LAN board or failover to another server occurs.
  

(2) Prerequisites for a physical host environment

The following conditions are the prerequisites for operating JP1 in a physical host environment. If you only execute JP1 in a logical host environment, the following prerequisites must also be satisfied as the system environment.

Table 3-3 Prerequisites for a physical host environment

Physical host component	Prerequisites
Server	A cluster must consist of two or more servers. The CPU performance must be sufficient for the processing to be performed. (For example, the CPU must be able to handle the startup of multiple logical hosts.) The real memory capacity must be sufficient for the processing to be performed. (For example, the servers must have sufficient memory capacity to handle the startup of multiple logical hosts.)
Disk	Files must be protected using a file system with a journal functionality or other measures so that the files will not be lost due to a system failure.
Network	Communication must be enabled using an IP address corresponding to the host name (result of the hostname command). (Clustering software or other programs must not modify the state to prevent communication.) The correspondence between the host name and IP address must not be modified while JP1 is running. (The correspondence must not be modified by clustering software or a name server.) In Windows, the LAN board corresponding to the host name must have the highest priority in the network binding settings. (Any other LAN board, such as that for heartbeat, must not have higher priority.)
OS and clustering software	The clustering software and its version must be supported by JP1. All patches and service packs required by JP1 and the clustering software must have been applied. The same environment must be set up for all of the servers so that the same processing can be continued after a failover occurs.

(3) Range supported by JP1

When you are using JP1 in a cluster system, JP1 only supports its own operations. Control over the logical host environment (shared disk and logical IP address) depends the clustering software.

If the above prerequisites for a logical or physical host environment are not satisfied or if there is a problem in controlling the logical host environment, JP1 does not support the problems that might occur with JP1 operations. In such a case, the clustering software or OS controlling the logical host environment must address the problem.

(4) Specifying a logical host

When executing a command, you must specify the logical host name so that the command will be executed on the logical host. If you do not specify the logical host name, the command will be executed on the physical host. You can specify the logical host name either by setting the name in the JP1_HOSTNAME environment variable or by specifying a command option. The following table describes each method.

Method	Description
JP1_HOSTNAME environment variable	Specify the logical host name in the JP1_HOSTNAME environment variable. If you specify a logical host name in both the command option and environment variable, the setting with the command option takes precedence.
Command option	Specify the command option in the following format: command -h logical-host-name. For details, see the description of each command.

Note

In Windows, do not set the JP1_HOSTNAME environment variable as a system environment variable or as a user environment variable. If so, this could disable services or otherwise disrupt program operation. Set the JP1_HOSTNAME environment variable at the command prompt or in a batch file.

(5) Rules for specifying logical host names

Comply with the following rules when specifying logical host names:

• Number of characters:1 to 196 bytes in Windows (63 bytes or less recommended)^#1; 1 to 255 bytes in UNIX (63 bytes or less recommended)^{#1, #2}
• Usable characters: Alphanumeric characters and hyphens.
  

  #1: These are the numbers of characters supported in JP1/Base. Your clustering software might not support these characters. Be sure to specify logical host names within the limitation of both JP1/Base and the cluster system you use. In actual operations, we recommend a host name of 63 bytes or less.

  #2: For the UNIX-only forced termination command (jbs_killall.cluster), you must specify a logical host name of 15 bytes or less. You cannot specify a logical host name that exceeds 15 bytes.

Notes

• Note the following if you specify the same name for both the logical host name and the physical host name (as output by the hostname command). We strongly recommend that the logical host name you specify in a cluster system be different from the physical host name.
  
  • Start JP1 on the logical host only.
    Start JP1 on the logical host only and do not start JP1 on the physical host.
    
  • Modify the settings for the event service environment.
    Comment out the line server * default, which is coded in the event server index file (index) by default. If this line remains in the file, the event database for the logical host is created on the local disk so that it cannot be taken over during a failover. You must complete the setup on both the primary and secondary server.
    
  • Modify the settings for the environment setting directory.
    To share the environment setting directory on the physical host, modify the settings as follows. You must complete the setup on both the primary and secondary server.
    In Windows:
    1. Create a definition file with the following contents.
    You can choose any name for the definition file.
    [JP1_DEFAULT\JP1BASE\]
    "JP1BASE_CONFDIR"="shared-folder\jp1base\conf\"
    2. Execute the following command to reflect the settings in the created definition file in the common definition information:
    jbssetcnf definition-file-name
    In UNIX:
    1. Create a definition file with the following contents.
    You can choose any name for the definition file.
    [JP1_DEFAULT\JP1BASE\]
    "JP1BASE_CONFDIR"="/shared-directory/jp1base/conf/"
    2. Execute the following command to reflect the settings in the created definition file in the common definition information:
    /opt/jp1base/bin/jbssetcnf definition-file-name
    
  • Restart the Hitachi Network Objectplaza Trace Library (HNTRLib2).
    To modify the host name while the system is running, you must restart the Hitachi Network Objectplaza Trace Library (HNTRLib2). To restart HNTRLib2, perform the following procedure:
    In Windows:
    1. Manually stop HNTRLib2 in the Services dialog box in the Control Panel.
    2. Change the host name.
    3. Manually start HNTRLib2 in the Services dialog box in the Control Panel.
    In UNIX:
    1. Use the hntr2kill command to stop HNTRLib2.
    2. Change the host name.
    3. Execute the following command to start HNTRLib2.
    hntr2mon -d &
    Trace information is not logged until you restart HNTRLib2. Stop all applications that are using HNTRLib2 before stopping HNTRLib2. Conversely, start HNTRLib2 before starting any application that uses HNTRLib2. For details on the hntr2kill command, see hntr2kill (UNIX only) in 13. Commands.
    
• If you are using DNS, use a host name that is not in FQDN format as the logical host name. For example, specify jp1v7 as the logical host name from jp1v7.soft.hitachi.co.jp. Make sure that names can be resolved by using this host name.
• In Windows, do not set the JP1_HOSTNAME environment variable as a system environment variable or as a user environment variable. If so, this could disable services or otherwise disrupt program operation. Set JP1_HOSTNAME at the command prompt or in a batch file.
• When using the UNIX forced termination command (jbs_killall.cluster), make sure the first 15 bytes of the logical host name uniquely identifies the host within the cluster system. The jbs_killall.cluster command determines the host by using the first 15 bytes and forcibly terminates the associated process. You cannot kill a process for a logical host name that exceeds 15 bytes.

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