After follow the guide below, i manage to set up a active-passive cluster node. But i notice that when the main fails and come back on, it does not take back the primary role. What setting i should configure in the crm to ensure that when the primary recover after a fail it takes back as primary from the back up machine?
https://www.theurbanpenguin.com/drbd-pacemaker-ha-cluster-ubuntu-16-04/
You would do this via an infinity location constraint. Something like:
location fs-on-alice fs_res inf: alice
Automatic fail-back is usually not suggested. In an ideal HA configuration it shouldn't matter at all what system is currently primary. Also, I have seen instances where a node is having intermittent panics/reboots every 10-20 minutes. Now you have services failing over, and stopping/restarting, several times an hour. If not for the location constraint and automatic fail-backs you would not have this behavior.