You can use Redhat Cluster Suit for the same.
Let's understand little bit of clustering
There is a different cluster for every problem. Generally speaking though, there are two main problems that clusters try to resolve. Performance and High Availability. and As per your requirement ( will continue to work even if a node in the cluster becomes inoperable (or needs maintenance, etc)), You can Setup High Availability clustering.
High Availability clustering
The cluster will provide a shared file systems and will provide for the high availability. You will be able to have servers live-migrate during planned node outages and automatically restart on a surviving node when the original host node fails.
Some Practical points
- You can Setup Staging environment in Vmware Esxi or Vmware Workstation to test your Application
- Minimum 2 Node ( with share storage to avoid split-brain situation ) and Maximum 16 nodes support as per Redhat Documentation
Cluster Management tools
In RHEL5.x/CentOS 5.x there are three tools
- Conga ( Manage Cluster from WebGUI )
- system-config-cluster (cluster administration graphical user interface (GUI) )
- ccs_tool (Command line tool, but not all options available )
In RHEL 6.x/CentOS 6.x system-config-cluster tool has been deprecated and removed without replacement