Installation guide

Changing the central_pro cessi ng mode for rg manager. For this change to take effect, a
global restart of rg manag er is required.
Changing the multicast address.
Switching the transport mode from UDP multicast to UDP unicast, or switching from UDP unicast
to UD P multicast.
You can restart the cluster using C o n g a, the ccs command, or command line tools,
For information on restarting a cluster with Co n g a, refer to Section 4.4, “Starting, Stopping,
Restarting, and Deleting Clusters”.
For information on restarting a cluster with the ccs command, refer to Section 6.2, “ Starting and
Stopping a Cluster”.
For information on restarting a cluster with command line tools, refer to Section 8.1, “Starting and
Stopping the Cluster Software” .
9.2. Clust er Does Not Form
If you find you are having trouble getting a new cluster to form, check for the following things:
Make sure you have name resolution set up correctly. The cluster node name in the
cl uster.co nf file should correspond to the name used to resolve that cluster's address over
the network that cluster will be using to communicate. For example, if your cluster's node names
are nod ea and no d eb make sure both nodes have entries in the
/etc/cl uster/cl uster.co nf file and /etc/hosts file that match those names.
If the cluster uses multicast for communication between nodes, make sure that multicast traffic is
not being blocked, delayed, or otherwise interfered with on the network that the cluster is using to
communicate. Note that some Cisco switches have features that may cause delays in multicast
traffic.
Use tel net or SSH to verify whether you can reach remote nodes.
Execute the ethto o l eth1 | g rep l i nk command to check whether the ethernet link is up.
Use the tcpd ump command at each node to check the network traffic.
Ensure that you do not have firewall rules blocking communication between your nodes.
Ensure that the interfaces the cluster uses for inter-node communication are not using any
bonding mode other than 0, 1, or 2. (Bonding modes 0 and 2 are supported as of Red Hat
Enterprise Linux 6.4.)
9.3. Nodes Unable t o Rejoin Clust er aft er 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 cl uster.co nf file. If the
cl uster.co nf file is different on any of the nodes, then nodes may be unable to join the cluster
post fence.
⁠Chapt er 9 . Diagnosing and Co rrect ing Problems in a Clust er
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