Why does a cluster resource failover not occur when one node loses connection with iSCSI storage in a Pacemaker cluster?

Issue

• In a pacemaker cluster, when one node lose connection with shared iSCSI storage, neither cluster fencing nor cluster resource failover occurred, only the iSCSI disk was shut down, and a multipath sub-path was removed, as observed in /var/log/messages:

Oct  5 05:53:27 node2 multipathd[798]: mpatha: reload [0 37748736 multipath 0 1 alua 1 1 service-time 0 1 1 8:16 1]
Oct  5 05:53:27 node2 iscsid[989]: iscsid: Connection2:0 to [target: iqn.2021-09.com.example:hadisk01, portal: ***.***.***.***,3260] through [iface: default] is shutdown.  <====
Oct  5 05:53:27 node2 iscsid[989]: iscsid: Connection3:0 to [target: iqn.2021-09.com.example:hadisk01, portal: ***.***.***.***,3260] through [iface: default] is shutdown.  <====
Oct  5 05:53:27 node2 kernel: scsi 33:0:0:0: alua: Detached
Oct  5 05:53:27 node2 multipathd[798]: check_removed_paths: sdc: freeing path in removed state  <====
Oct  5 05:53:27 node2 multipathd[798]: 8:32: path removed from map mpatha
Oct  5 05:53:28 node2 multipathd[798]: mpatha: map in use
Oct  5 05:53:28 node2 multipathd[798]: mpatha: can't flush
Oct  5 05:53:28 node2 multipathd[798]: mpatha: reload [0 37748736 multipath 0 0 0 0]
Oct  5 05:53:28 node2 kernel: scsi 34:0:0:0: alua: Detached
Oct  5 05:53:28 node2 multipathd[798]: check_removed_paths: sdb: freeing path in removed state. <====
Oct  5 05:53:28 node2 multipathd[798]: 8:16: path removed from map mpatha