As I am aware, you would have two options depending on your configuration:
Change the primary_conninfo value on the second standby's recovery.conf to point to the standby that has been promoted to master. However, I think this would require that instance to be rebooted for the configuration changes to take effect
Modify the DNS entries so that the host value in primary_conninfo points to the new master rather than the old master
I am getting ready to take my master server out of service today and promote the slave to take it's place. In my current setup I have one master server which ships WAL files to two separate slave servers.
My plan is to promote one of those slaves. How do I get the slave that I promoted to start replicating to the other slave the moment I trigger it's promotion?