Oracle Weblogic 12c Administration - Part 6

 

WebLogic Cluster:
    * It is a logical group of managed servers from the same domain.

    * It provides high availability for the web application, web services, JMS and EJB.

    * We can add a server dynamically.

Advantage of Clustering:

Pros and Cons of Single tier and multi-tier cluster:

WebLogic Proxy Plug-ins:

* Load balancer send a client requests to WebLogic server in a round robin method.

* It will help to send a request to failed or unavailable server in the domain

* It routes the request based on the WebLogic server cookies.

Oracle HTTP Server (OHS)

* It is based on Apache web server

* Installed with the WebLogic Server Plug-in module (mod_wl_ohs) by default

            include "mod_wl_ohs.conf"

* This plugin should be configured by using the mod_wl_ohs.conf file.

* The main configuration file is httpd.conf. It will contain a WebLogic plug-in configuration file as well.

* Configuration file of OHS can found under /Domain_name/config/fmwconfig/components/OHS/instances/OHS_instances_name

Unicast & Multi cast:

Troubleshooting a cluster issue:

* We have to check the WebLogic server Logs

* We have to analsis the OHS Logs

/Domain_name/servers/instance/logs

* Recording the OHS error under this ohs_instance_name.logs

* Recording the access request log under this access_log file.

* It may be due to OHS to WebLogic server connectivity issues

* Multicast connection issues

        * Request session time out issue

Transaction:

* A transaction is a process which handle a group operations as single flow.

It have a four key values as follows:

* Atomic : It will complete with full operation not permit with partial success.

* Consistent : A transaction change a system from one state to other state.

* Isolated : Each transaction will run independently.

* Durable : It will stay in the system if failure of the system.

WebLogic Log location:

Severity Low to High level of log: