Tuesday, March 23, 2010

High available Fusion Middleware Cluster

On a project I am building a High Available Soa Suite 11g Cluster. This is not so difficult thanks to Weblogic and when you follow the guides of Antony Reynolds or Marc Kelderman, they did a great job.
High Availability for FMW is not so different then for a normal Weblogic Cluster HA.The Soa Suite Documentation contains a great document called Enterprise Deployment Guide For Oracle SOA Suite , this document shows all  the best practices how to setup a High Available Weblogic Cluster.
When you just want a Weblogic Cluster or a Soa Suite Weblogic Cluster for the performance you can follow the guide of Marc Kelderman. This is a cluster without shared storage for the Domain, Transaction logs and JMS servers. This means you can't manual migrate the Admin Server to a other machine and no automatic Managed Server Migration by the Node managers. And more important, you can loose transactions and JMS messages when a Managed Server fails. When you also use resource adapters in the Soa Suite Cluster you need to make sure that the resource adapter deployment plan with all the EIS connections is available on every Managed SOA Server .

To solve this you need to have a shared storage. This shared storage needs to be available on every machine and because of the shared storage, every machine can start the Admin Server or Managed Servers. The migrated Managed Server can pick up the transaction logs and JMS messages of the failed Managed Server( No data loss)
In the Enterprise Deployment Guide Document, Oracle did every right to make a perfect cluster like
  • Using Virtual IP addresses
  • A Domain folder for the Admin Server and a separate one for the Managed Server
  • FMW installation on the Shared storage and two installs one for the Admin and one for the Managed Server
  • Oracle RAC for the leasing table
The only downside of this configuration is the NFS share, when you need to patch or configure this NFS share the cluster must go down. Else it would be possible to never shutdown all the Managed Servers in the Cluster. Maybe Oracle or Sun can solve this by some SAN hardware solution.
And maybe in the next version of this Solution, Oracle can give some more detail how to setup a Weblogic Cluster when every WLS machine has two network interfaces on different switches ( to solve network failures ).

Here are the important chapters you should read to make a HA Soa Cluster besides the document of Marc Kelderman.

Chapter 2.2.3 IPs and Virtual IPs

Chapter 2.3 Shared Storage and Recommended Directory Structure

Chapter 8  Server Migration
  • How to setup the Leasing table in Oracle RAC
  • Multi DataSource
  • Configure the Node Managers
  • Configure the Cluster for migration in the Weblogic Console
  • Test the Server Migration.

Chapter 11.5 Using Shared Storage for Deployment Plans And Soa Infrastructure Applications Updates