10.3. Nodes Unable to Rejoin Cluster after Fence or Reboot

If your nodes do not rejoin the cluster after a fence or reboot, check for the following things:

Clusters that are passing their traffic through a Cisco Catalyst switch may experience this problem.
Ensure that all cluster nodes have the same version of the cluster.conf file. If the cluster.conf file is different on any of the nodes, then nodes may be unable to join the cluster post fence.
As of Red Hat Enterprise Linux 6.1, you can use the following command to verify that all of the nodes specified in the host's cluster configuration file have the identical cluster configuration file:
```
ccs -h host --checkconf
```
For information on the ccs command, see Chapter 6, Configuring Red Hat High Availability Add-On With the ccs Command and Chapter 7, Managing Red Hat High Availability Add-On With ccs.
Make sure that you have configured chkconfig on for cluster services in the node that is attempting to join the cluster.
Ensure that no firewall rules are blocking the node from communicating with other nodes in the cluster.