This is most likely configured using the fencing and fence-peer keyword in your DRBD configuration.
If the nodes are powering off then you likely have it configured with fencing resource-and-stonith;. The default here is dont-care.
With the “fencing dont-care” I have the same behaviour - unplug all (two) dedicated drbd replication links and both cluster nodes powered off.
Exactly the same behaviour for “fencing resource-only”
It might also be possible that Pacemaker is fencing, and powering-down, the nodes.
Perhaps the Corosync communication is configured to use the same links?
OMG… I may missed that.
Here is below my corosync.conf
[root@memverge anton]# cat /etc/corosync/corosync.conf
totem {
version: 2
cluster_name: cluster_anton
transport: knet
crypto_cipher: aes256
crypto_hash: sha256
cluster_uuid: 7a103b6fade74c019654504150bdd64b
knet_mtu: 8982
}
nodelist {
node {
name: memverge
nodeid: 27
quorum_votes: 1
ring0_addr: 192.168.0.6
ring1_addr: 1.1.1.6
}
node {
name: memverge2
nodeid: 28
quorum_votes: 1
ring0_addr: 192.168.0.8
ring1_addr: 1.1.1.8
}
}
quorum {
provider: corosync_votequorum
two_node: 1
}
logging {
to_logfile: yes
logfile: /var/log/cluster/corosync.log
to_syslog: yes
timestamp: on
}
[root@memverge anton]#
I want that drbd replication use two links (ring0 and ring1), but pacemaker/corosync communication goes through another links -
10.72.14.152 memverge
10.72.14.154 memverge2
You may also want to consider both changing the fencing action from off to reboot,
and configuring a pcmk_delay_base to the fencing action of one of the nodes.
By delaying the fencing action of one node you should always be left with one survivor and not have both power down or reboot at the same time.
Since this is two nodes active/standby cluster and two resources (ha-nfs and ha-iscsi) always run together on the same node, I tried next commands -
[root@memverge anton]# pcs property set priority-fencing-delay=15s
[root@memverge anton]#
[root@memverge anton]# pcs resource defaults update priority=1
Warning: Defaults do not apply to resources which override them with their own defined values
[root@memverge anton]#
And now if I unplugged all drbd replication links, there is fencing for standby node only.
It seems exactly what I was looking for.
Thank you!!