Cluster ports

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When you configure an appliance cluster, you are required to specify the starting port number for a range of ports to be dedicated to the services that are provided by the cluster.

It is important to note that these ports are for internal use only and are not used by the cluster for communication between nodes. All of the communication that takes place between nodes in the cluster occurs over port 22. This means that if your nodes are separated by a firewall, you only need to open up traffic on port 22 to allow the cluster services of the various nodes to communicate with each other.

The following diagram illustrates the communication requirements of the various roles in the cluster.
Figure 1. Communication in a cluster using port 22
Communication in a cluster using port 22

If you want to manually configure a DSC client on a node within the cluster, use the following addresses and ports:

Note: The following examples assume that the first port is 2020.
Node Port Example
Primary first_port + 15 127.0.0.1 15 127.0.0.1:2035
Secondary first_port + 16 127.0.0.1 16 127.0.0.1:2036
Tertiary first_port + 17 127.0.0.1 17 127.0.0.1:2037
Quarternary first_port + 18 127.0.0.1 18 127.0.0.1:2038

Some additional settings are required to configure a DSC client on a node within the cluster. Set the priority for each distributed session cache server to 9 within the server stanza entry in the [dsess-cluster] stanza. Also set the load-balance stanza entry in the [dsess-cluster] stanza to no. The DSC does not support load balancing. Setting the load-balance configuration entry to no prevents connection attempts to servers for which the connection attempts will certainly fail.