Simple WebLogic Cluster
In a simple WebLogic cluster there are one or more WebLogic instances per webserver host and there are more than one webserver host for redundancy. There is only one WebLogic proxy server running on a separate host.
The architecture diagram is shown below:
For this setup:
􀂃 Use WebLogic Proxy server serving HttpClusterServlet web application.
􀂃 All instances must use the same HTTP/HTTPS port e.g. 5010/5011 in the example. This requires
IP Aliasing if the host does not have dedicated network interfaces for each webserver instance
􀂃 One proxy server load balances across all the WebLogic instances
􀂃 The proxy must pass all calls to the webserver instances
􀂃 WebLogic proxy server and WebLogic servers providing PIA are run as WebLogic Managed
Servers
Advantages:
􀂃 Simple to setup
􀂃 Low cost solution
Disadvantages:
􀂃 Proxy adds an additional layer
􀂃 WebLogic proxy requires IP Aliasing for running multiple instances
􀂃 WebLogic proxy is a single point of failure.
􀂃 Very low scalability. The WebLogic proxy will soon become a scalability bottleneck as new webservers are added to the pool particularly when going over SSL.
