Configuring TCP/IP stack affinity

Before you begin

Before configuring TCP/IP stack affinity for WebSphere Application Server for z/OS on a system with multiple stacks, you must:
  1. Establish the Application Server's stack affinity to the desired TCP/IP stack so that all socket communications are bound to that stack
  2. Establish the Application Server's allocation of the proper host name resolution configuration data sets so that host name lookups have the desired results.

Why and when to perform this task

Setting up TCP/IP stack affinity can provide network isolation for one or more of your applications. For example, if you have multiple OSA Features, each one might connect your system to a different network. You can use the common INET physical file system (C_INET PFS) to assign a TCP/IP stack to each OSA Feature. This physical file system allows you to configure multiple physical file systems (network sockets) and make them active concurrently. To set up the common INET physical file system, specify common INET through the NETWORK DOMAINNAME parameter of SYS1.PARMLIB(BPXPRMxx).

If you plan to configure WebSphere Application Server for z/OS to use a non-default TCP/IP stack, consult z/OS UNIX System Services Planning, and z/OS Communications Server: IP Configuration Reference, for details.

Note:

To configure TCP/IP stack affinity for WebSphere Application Server for z/OS on a system with multiple TCP/IP stacks

Steps for this task

  1. Configure the data set for each Application Server's host name resolution.

    In the administrative console, click Environment > Manage WebSphere Variables > New.

    1. Add the RESOLVER_CONFIG variable and specify the data set name for value.
    2. Export the RESOLVER_CONFIG variable in client shell scripts.
    • You can also use JCL to specify the name resolution configuration data set. To use JCL, add //SYSTCPD DD DSN=some.tcpip.DATA,DISP=SHR to the server JCL. The RESOLVER_CONFIG variable overrides the SYSTCPD DD statement.
    To set the RESOLVER_CONFIG variable in the was.env file for the Daemon, prefix the variable with DAEMON_. This additional information causes the transformer that generates the was.env files to add the variable to the was.env file for the Daemon. See z/OS Communications Server: IP Configuration Reference, for more information on the RESOLVER_CONFIG variable.

    Note: If you are setting this variable for the Daemon, you probably want to set it at the cell level to give all the Daemons in that cell the same setting. Unless one of the Daemons is serving multiple nodes, if for some reason you need to specify different settings for different Daemons in a cell, , you can set this variable at the node level.

  2. Establish the Application Server's TCP/IP stack affinity to the desired stack.
    1. In the administrative console, click Environment > Manage WebSphere Variables and set the _BPXK_SETIBMOPT_TRANSPORT variable to the value of the desired transport.
      If this variable does not exist, click New and add it.
    2. Export the _BPXK_SETIBMOPT_TRANSPORT variable in client shell scripts.
    To set the BPXK_SETIBMOPT_TRANSPORT variable in the was.env file for the Daemon, you must prefix the variable with DAEMON_. This additional information causes the transformer that generates the was.env files to put add the variable to the was.env file for the Daemon. Because the _BPXK_SETIBMOPT_TRANSPORT variable already has a leading underscore, the final version of this variable, when set for the Daemon, contains two underscores preceding the variable name, as shown here DAEMON__BPXK_SETIBMOPT_TRANSPORT. See z/OS UNIX System Services Planning, for more information on the _BPXK_SETIBMOPT_TRANSPORT variable.

    Note: If you are setting this variable for the Daemon, you probably want to set it at the cell level to give all the Daemons in that cell the same setting. Unless one of the Daemons is serving multiple nodes, if for some reason you need to specify different settings for different Daemons in a cell, , you can set this variable at the node level.

  3. If you are not running multiple TCP/IP stacks, set the JVM property -Dcom.ibm.websphere.singlehost to 1 in each controller and servant JVM.
    To modify this property, in the administrative console click Servers > Application Servers >server Process Definitions, and then click either controller > JVM Configuration or Servant > JVM Configuration.




Searchable topic ID:   truntcpmultistack
Last updated: Jun 21, 2007 9:56:50 PM CDT    WebSphere Application Server for z/OS, Version 5.0.2
http://publib.boulder.ibm.com/infocenter/wasinfo/index.jsp?topic=/com.ibm.websphere.zseries.doc/info/zseries/ae/trun_tcpmultistack.html

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