If you are on this page, I believe you must have some information about websphere application server. Installation and uninstallation is one of the primary activity that a websphere Application server administrator need to plan thoroughly . Ideally, It should not be WAS admin alone decision to setup middleware infrastructure. If possible, we should involve Application Team , Network Team , DBA , Security Management Team ( SiteMinder Team ) , and others . They may or may not add values to our planning but its good practice to inform all teams about our installation approach, If WebSphere is being installed first time as application server in project.
By the time , you would be reading this post may be WebSphere Application 10Th or 11th version would have release but it’s important to decide which version to use. Its best practice to go with one version lower than the latest release version.
The identify which version should be an ideal option to go with , we always recommend to have a discussion with application development Team to understand the version of JSP specifications, Servlet , Java Enterprise Edition version , EJB versions etc they are going to use in their code. Get a details list of specifications that they will be using in their application development and compare with the best fit.
An admin, has to make sure which version of websphere application server is matching with the requirements. Its also recommended, not to go for latest WebSphere release in production environment, let the new release get stabilized otherwise admin may have to apply fixpacks very frequently.
Prerequisite
Operating System: From WebSphere Application server 8.x, installation of WAS binaries /fix-packs are managed through Installation Manager. Installation manager that comes with WebSphere media is by default compatible with 32 Bit. So, be careful to download 64 bit of IBM Installation manager, if your operating system is 64 bit.
If you have created a new Ubuntu VM or have just got a new Linux , Unix, Aix etc operating system, then we need to plan users, roles, installation directories, file permissions etc ( A sample exercise is shown below :
Step 1: create a user and a group .
adduser wasadmin
groupadd middleware
Step 2 : Add the above user as part of sudo group
usermod -aG sudo wasadmin
Step 3: Change ownership of your installation directory. It should be owned by above user:group.
Chmod –R wasadmin:middleware /was
Access on Operating System: We should have root/sudo privilege to install.
Space requirement: There should be minimum 1 GB of free disc space under /tmp during installation and minimum 2.5 GB for installing WebSphere. We need 25 MB to 50 MB for each profile creation.
Umask Setting: This is important to set before starting installation. Its recommended to have umask value set as “022 “, so that all the files that will be created during was installation will have “755” ( Default value – umask value = 777 - 022 = 755 ) permission.
Ulimit setting: It defines the number of open file per process. It’s a method to restrict OS resources to be opened/used by a program so that the particular program should not hamper other programs. If the program reaches to the limit of open files then, we will get to see an error message like “Too many Files open”. To fix this issue, we need to either increase the ulimit value or to check our development team to fine tune the code. According to IBM, ulimit value should be “8192” while installing the websphere packages.
You can verify the existing ulimit value and update it as per the example shown below:
To check: ulimit –n
To set : ulimit –n 8192
User limits - limit the use of system-wide resources.
Syntax
ulimit [-acdfHlmnpsStuv] [limit]
Options
-S Change and report the soft limit associated with a resource.
-H Change and report the hard limit associated with a resource.
-a All current limits are reported.
-c The maximum size of core files created.
-d The maximum size of a process's data segment.
-f The maximum size of files created by the shell(default option)
-l The maximum size that can be locked into memory.
-m The maximum resident set size.
-n The maximum number of open file descriptors.
-p The pipe buffer size.
-s The maximum stack size.
-t The maximum amount of cpu time in seconds.
-u The maximum number of processes available to a single user.
-v The maximum amount of virtual memory available to the process.
ulimit provides control over the resources available to the shell and to processes started by it.
The soft limit is the value that the kernel enforces for the corresponding resource.
The hard limit acts as a ceiling for the soft limit.
Open limits.conf ( "/etc/security/limits.conf" ) in vi editor and add below mentioned values at the end.
wasadmin soft core unlimited
wasadmin hard core unlimited
wasadmin hard fsize unlimited
wasadmin hard nproc 31450
wasadmin soft nofile 102400
wasadmin hard nofile 102400