- In /etc/nsswitch.conf, put "files" before "dns" to have the hosts file entries take precedence over DNS. For example:
hosts: files dns
In /etc/hosts file, add an entry for each host in the HA pair, as in the following example:
192.168.144.128 host1.domain.com host1
192.168.144.137 host2.domain.com host2
It is important to adhere to the correct format of /etc/hosts files in order to reduce errors. If you have both dotted hostnames and short versions, you need to list the dotted hostnames with the most dots first and the other versions subsequently. This should be done consistently for both HA server entries in each of the two /etc/hosts files. Note in the examples above that the aliases are listed last.
Set up the SSH key
SSH must be installed on both hosts in a way that gives the user who runs the Controller passwordless SSH access to the other Controller system in the HA pair. You can accomplish this by generating a key pair on each node, and placing the public key of the other Controller into the authorized keys (authorized_keys) file on each Controller.