Recover from split brain
https://docs.linbit.com/doc/users-guide-84/s-resolve-split-brain/
stop cluster, on broken node first!
sudo pcs cluster standby jtel-2-5-pn-1
sudo pcs cluster standby jtel-1-5-pn-1
on broken node
sudo drbdadm disconnect jtelshared
sudo drbdadm secondary jtelshared
sudo drbdadm connect --discard-my-data jtelshared
on the healthy node
sudo drbdadm primary jtelshared
sudo drbdadm connect jtelshared
start cluster
sudo pcs cluster unstandby jtel-1-5-pn-1
sudo pcs cluster unstandby jtel-2-5-pn-1
check cluster
sudo pcs resource show
check DRBD
sudo cat /proc/drbd