WebSphere Application Server for z/OS follows the CORBA standard, Internet Inter-ORB Protocol (IIOP), for communications. Accordingly, you must consider changes to your TCP/IP network and modify the TCP/IP configuration.
This section provides background information about changes you will need to make to your Domain Name Server (DNS) and TCP/IP. The actual steps to perform are in the customized instructions of the Customization Dialog.
Tips on TCP/IP and WebSphere Application Server for z/OS
Consider the following for your TCP/IP network on z/OS.You may, for instance, intend to expand your business applications beyond the monoplex to a full sysplex configuration for performance reasons or to prevent a single point of failure. Several considerations come to bear here.
Several DNS implementations and network router implementations allow the use of a generic location service daemon IP name while dynamically routing network traffic to like-configured servers. If you intend to expand your system beyond a monoplex, it might be worthwhile to use one of these implementations from the start. Non-round-robin DNS name servers limit your ability to expand without retrofitting a name server that allows dynamic network traffic routing.
Recommendation: If you are running in a sysplex, set up your TCP/IP network with Sysplex Distributor. This makes use of dynamic virtual IP addresses (DVIPAs), which increase availability and aid in workload balancing.
Beyond Sysplex Distributor, you have your choice of the following DNS and router implementations on or off z/OS:
For your base Application Server, choose the host name of the server under which you are running. For your deployment manager, choose a generic IP name that can resolve to any or all of the systems where location service daemons run.
You must define the location service daemon host IP name during installation and customization. Use the location service daemon IP name you chose.
Note: The administrative console has a location service daemon configuration page on which you set location service daemon variables.
If you change the location service daemon port number, you can access existing objects after you recycle all your servers. You cannot, however, access the following:
If you install WebSphere Application Server for z/OS V on a system that already contains WebSphere Application Server V4.0.1 for z/OS and OS/390, double-check your current location service daemon port value (default for WebSphere Application Server V4.0.1 for z/OS and OS/390 is 5555).
These are initially set in the Customization Dialog, but you can subsequently change them in the Administrative Console. Access the location service daemon configuration page through the Administrative Console navigation bar (on the left side of screen) under System Administration. If you need to use the Internet Inter-ORB Protocol (IIOP) through a firewall, ensure that your firewall supports IIOP.
When recovering a server somewhere other than its configured system, ensure that the same port is not already in use on the system on which it is recovering. If it is, configure the server with a unique port to avoid a conflict.
If comparing WebSphere Application Server for z/OS V and WebSphere Application Server V for other platforms, realize that only WebSphere Application Server for z/OS V has an ORB SSL port.
HTTP and HTTPS ports are found in individual servers under the Web container transports, which are in the administrative console as 'additional properties' on the Web container configuration page (which is off the server configuration page).
Watch for HTTP transport port conflicts if you previously installed WebSphere Application Server V4.0.1 for z/OS and OS/390.
Ensure you set up the following port assignments (along with those in the z/OS port assignments chart) on servers that require them in the administrative console:
See the administrative console and the InfoCenter for more information on the WebSphere variables and how to set their values.
You define ports differently depending on whether they are for the first server or subsequent servers. The first server you create is defined, along with its ports, through the Customization Dialog. You have the ability to explicitly specify the ports as you define the server. Subsequent servers and their ports are defined through the administrative console. This means that you define the server first and the ports are automatically assigned. Then, once defined, you can inspect and change the port definitions through the administrative console.
The -t value specifies the time (nn, in seconds) between refreshes of cell names and addresses and of the weights associated with those names and addresses. The default is sixty seconds. Reducing the -t value will shorten the lapse time required to register the location service daemon IP name with the DNS, but will also increase DNS processing overhead. In our testing, we used an interval of 10 seconds.
If you use the z/OS DNS, you have to set a location service daemon variable. Do this by setting WebSphere Variable at cell level:
daemon_wlmable=1
Note: You can perform this for only one cell in a sysplex at a time.
For details, see z/OS Communications Server: IP Configuration Reference.