Before beginning any WAS installation, it is recommended you answer the following three questions to help prepare and plan for an installation:
What version of WAS is required to support your applications?
Investigations are made to ensure that your application(s) will run in the version of WAS you intend to install. A good WAS version compatibility matrix can be found at the following URL: http://en.wikipedia.org/wiki/Websphere. You can also consult the summary table titled Reference table for supported standards which was presented in Chapter 1, WebSphere Application Server 8.0: Product Overview. It is also recommended you speak to your application developers or application vendors to accurately assess (Java Virtual Machine (JVM) requirements.
Are there any OS tweaks for the platform required for the chosen version of WAS?
It is important to understand what version of Operating System (OS) you are going to use. First, decide which platform you are going to install on and then research what the prerequisites are for that platform. Each platform may have certain OS changes or optimizations, which are stipulated for correct installation of WAS. For detailed OS requirements, you can refer to the WAS product documentation at the following URL:
What version of OS and fix packs are required to support the chosen version of WAS?
Not only do you need to understand the base installation version, you may also want to understand what the latest fix packs are to ensure that your version of WAS is fully up-to-date to the level required. You can go to IBM Support Fix Central located at the following URL to find the latest WebSphere fix pack versions http://www-933.ibm.com/support/fixcentral/. We will cover more about maintenance and fix packs in Chapter 11,Product Maintenance.
Installation scenarios
Before beginning an installation, it is advised that you think about the type of WAS install you wish to perform. There are several installation scenarios and knowing which components are available might influence your chosen installation path. You may also wish to think about coexistence or interoperability with other WAS implementations or helper services. Helper services are other applications and/or technologies that may be required for your applications to run correctly on WAS and function as per their design. This means you may have to consider other installation requirements in addition to those of WAS.
The WAS installation process requires two main actions:
Installation of base binaries (which are the core executables).
Profile creation.
The base binaries are the product mechanics made up of executables and shell scripts, and can be shared by one or many profiles. Profiles exist so data can be partitioned away from the underlying core runtime. Simply put, a profile contains an Application Server. When an Application Server is running, the server process may read and write data to the underlying configuration files and logs. So, by using profiles, transient data is kept away from the base product. This allows us to have more than one profile using the same base binaries, and also allows us to remove certain profiles without affecting other profiles. Another reason for separating the base binaries is that we can upgrade the product with maintenance updates and fix packs without having to re-create all profiles. Sometimes you do not want a specific profile to be updated. WAS profile management has been designed for flexibility.
A conceptual diagram of the WAS installation components is shown next:
Profile types
During the installation process, you can decide to install different profile types. There are two main profile types: application server profiles and management profiles. Your installation scenarios will determine the combination of profile types you will be selecting throughout the installation wizard.
The following table explains the different profile types: