When you create a cluster in the command-line console, the cluster
node identifier, the current App Controller role, and a prompt to enter the
shared key appear. You create the shared key on the cluster head and then use
the same shared key for each VM in the cluster.
You must configure the host name on the cluster head. This
information is replicated to the service nodes automatically as part of
configuration sharing. The host name appears in the request URLs to be
distributed in the cluster. Each service node in the cluster must also have the
same shared key to establish secure tunnels. If the shared key on the cluster
head and service node do not match, the two VMs cannot communicate.
The shared key must be eight characters with at least one uppercase
letter, one lowercase letter, one numeric, and one special character that
includes one of the following symbols: [!#$&].
After you enter the shared key, you restart App Controller. After
App Controller restarts and you log on again to the command-line console, a
message appears that states that the App Controller VM is now the cluster head.
If you have two App Controller VMs in a high availability pair, use
the virtual IP address when you configure the service node. Both VMs function
as a cluster head. For example, if the primary VM in the high availability pair
fails for any reason, the secondary VM takes over and serves user requests.