This topic describes how to install WebSphere Application Server products on Red Hat Enterprise Linux 3 (RHEL 3) systems.
Before you begin
After installing the V5.1.0 product on RHEL 3, install Fix Pack 1. Also install WebSphere Application Server V5.1.1 cumulative fix for IBM SDK, Solaris Java 2 SDK, and HP-UX Java 2 SDK to update the IBM Developer Kit for Linux, Java Technology Edition software that IBM uses with the Version 5.1.1 WebSphere Application Server product. The new service level is 1.4.2 SR1.Why and when to perform this task
Use the following procedure to install WebSphere Application Server products on Red Hat Enterprise Linux 3.Steps for this task
You must install the following packages on Red Hat Enterprise Linux V3.0 for xSeries platforms:
The following recommended packages are needed for developing and building Java Native Interface (JNI) libraries for your J2EE applications. If you do not intend to compile JNI libraries on the machine, you can omit installing the following packages without affecting RHEL or WebSphere Application Server:
The following package is required for Red Hat Enterprise Linux V3.0 for iSeries and pSeries platforms:
You must install the following packages on Red Hat Enterprise Linux V3.0 for S/390 (z/VM and VM/ESA) platforms:
You can install a later release of any of these packages.
Upgrade RHEL 3.0 to service level 1 by downloading and installing the service updates from Red Hat. To do this, download updates related to service level 1 through the up2date tool included with Red Hat Linux V3.0. Alternatively, the entire set of installation images for Red Hat Enterprise Linux V3.0 service level 1 can be downloaded from the Red Hat Network.
You must have an account with Red Hat Network to download these updates. Update levels past Update 1 are also supported on the assumption of forward compatibility. Update 1 is the minimum required patch level of RHEL 3 for support of WebSphere Application Server, Version 5.1.
If you do not upgrade to service level 1, certain national language issues in the released version of GLIBC included in Red Hat Enterprise Linux V3 might cause Java Virtual Machine (JVM) failures due to segmentation faults. These failures can occur during installation when the locale is set to anything other than an English locale.
Prereq checker messages
The prerequisites checker program for the base V5.1.0.0 product does not recognize Red Hat Enterprise Linux V3.0 as a supported operating system. If you install all prerequisite packages from the previous step, and if you download and install the service level 1 update, ignore any message you receive from the prerequisites checker program that RHEL 3.0 is an unsupported operating system. Continue the installation.
Upgrading RHEL 3.0 to service level 3 (update 3) is recommended. The Edge Components require update 2 for RHEL 3.0.
Avoiding a segment fault in the JVM at installation
If you are installing from an operator console attached to the RHEL 3 U1 machine, and you receive a message that is similar to the following message, you might be experiencing a known limitation of installing WebSphere Application Server, Version 5.1 on RHEL 3 U1. The message is:
A suitable JVM could not be found
The problem stems from behavioral changes in GLIBC that Red Hat Enterprise Linux V3.0 provides. In certain situations a “Segmentation Fault” or a JDK hang occurs when running the JVM embedded in the installer. The problem does not always occur. Most commonly, the problem occurs when you run the installation program, log off of the root user, log back on to root, and run the installation again on the operator console that is attached to the machine (not a telnet or ssh session).
When the problem occurs, the installation fails immediately with the above message. To see if the JVM is experiencing a “Segmentation Fault” error, you can test it by running the following command:
/mnt/cdrom/platform/linuxi386/jdk/java/jre/bin/java –version
If the command generates a "Segmentation Fault" message or seems to hang, you are experiencing a problem caused by an unusual interaction between the JVM and the version of GLIBC shipped with RHEL 3. This most commonly occurs if the console ‘root’ was logged into is logged completely out, then logged back in. In a nutshell, the JDK inadvertently starts trying to allocate an unusually large block of memory for use with main thread stack when the problem occurs. There are two ways to work around this issue:
Rebooting the system resets some internal states, which cause the JDK to properly allocate the primary thread stack memory again.
Set the thread size to limit the amount of memory that the JVM attempts to allocate to the thread stack. To set the stack size, run the following command in the shell where you intend to run the installer:
ulimit -s size
The size variable can be any value from 2048 to 8196. For example: ulimit –s 2048 instructs the current shell environment to fix the maximum stack size at 2 MB.
Avoiding installation hangs during installation on x86 (xSeries) platforms
If you encounter an installer hang during installation, you are likely encountering a known bug with the new POSIX threading implementation provided in RHEL 3 known as NPTL, or Native POSIX Threading Library. The problem is specific to x86 (Intel 32 bit and compatible processors) hardware and in rare instances can cause the installer to hang. The hang occurs in the JVM garbage collector when NPTL-based GLIBC does not properly release a thread lock when requested.
Two simple methods exist to bypass the problem:
LinuxThreads does not exhibit this failure and can be used to run the installer. To enable LinuxThreads for the installer, you must set two environment variables in the shell where you intend to run the installer. The two commands you must run are:
export RPM_FORCE_NPTL=1 export LD_ASSUME_KERNEL=2.4.19
To verify that the variables are set, run the following commands:
env | grep RPM_FORCE_NPTL env | grep LD_ASSUME_KERNELEach command returns the variable setting.
Now you are ready to install the WebSphere Application Server product on the RHEL V3 system.
Continue the rest of the steps in this procedure after the installation is complete.
At this time, the most current fix pack is Fix Pack 1 for V5.1.0.
See the download page for base and Network Deployment for more information.
Always install the latest cumulative fixes as they are released. See Cumulative Fix Strategy for WebSphere Application Server V5.0 and V5.1 for more information.
See Installing interim fixes, cumulative fixes, and fix packs for more information about installing a fix pack, cumulative fix, or interim fix.
The V5.1.0 Cumulative Fix for SDKs contains service for the SDK that is used by WebSphere Application Server products. The SDKs are the:
The V5.1.0 Cumulative Fix for SDKs is for all Version 5.1 WebSphere Application Server products. The cumulative SDK fixes include a fix for the GLIBC behavioral changes that are responsible for the over-allocation of memory to the main stack. Once installed, you should no longer see the rare JVM segmentation faults or hangs when starting the WebSphere Application Server.
This collection of fixes for Version 5.1 updates the WebSphere Application Server base product or the Network Deployment product to Version 5.1.0.3.
Cumulative Fix 3 includes all of the interim fixes in Cumulative Fix 2.
What to do next
Always install the latest cumulative fixes as they are released, if possible. For additional information on cumulative fixes, read the Cumulative Fix Strategy for WebSphere Application Server V5.0 and V5.1 products .
Known problems
See the Preparing Red Hat Enterprise Linux 3 (RHEL 3) to run WebSphere Application Server V5.1 products technote for known problems related to Red Hat 3.3 on WebSphere Application Server V5.1.1 products.