Hi! 

still no luck - somehow /var/lib/nfs cannot be unmounted after cleanly after ocf:heartbeat:nfsserver was started

Jun  6 06:18:44 blofecn2 pacemaker-controld[7732]:  notice: Requesting local execution of stop operation for nfs_daemon on blofecn-node2 
Jun  6 06:18:44 blofecn2 nfsserver(nfs_daemon)[3258604]: INFO: Stopping NFS server ...
Jun  6 06:18:44 blofecn2 systemd[1]: Stopping NFS server and services...
...
Jun  6 06:18:44 blofecn2 kernel: [1208580.651530] nfsd: last server has exited, flushing export cache
Jun  6 06:18:44 blofecn2 systemd[1]: nfs-server.service: Deactivated successfully.
Jun  6 06:18:44 blofecn2 systemd[1]: Stopped NFS server and services.
Jun  6 06:18:44 blofecn2 systemd[1]: Stopping NFSv4 ID-name mapping service...
Jun  6 06:18:44 blofecn2 systemd[1]: Stopping NFS Mount Daemon...
Jun  6 06:18:44 blofecn2 rpc.mountd[21260]: Caught signal 15, un-registering and exiting.
Jun  6 06:18:44 blofecn2 rpc.idmapd[21256]: exiting on signal 15
Jun  6 06:18:44 blofecn2 nfsserver(nfs_daemon)[3258604]: INFO: Stopping sm-notify
Jun  6 06:18:44 blofecn2 systemd[1]: nfs-mountd.service: Deactivated successfully.
Jun  6 06:18:44 blofecn2 systemd[1]: Stopped NFS Mount Daemon.
Jun  6 06:18:44 blofecn2 systemd[1]: nfs-mountd.service: Consumed 8.098s CPU time.
Jun  6 06:18:44 blofecn2 systemd[1]: nfs-idmapd.service: Main process exited, code=exited, status=1/FAILURE
Jun  6 06:18:44 blofecn2 systemd[1]: nfs-idmapd.service: Failed with result 'exit-code'.
Jun  6 06:18:44 blofecn2 systemd[1]: Stopped NFSv4 ID-name mapping service.
Jun  6 06:18:44 blofecn2 systemd[1]: nfs-idmapd.service: Consumed 1.673s CPU time.
Jun  6 06:18:44 blofecn2 nfsserver(nfs_daemon)[3258604]: INFO: Stopping rpc.statd
Jun  6 06:18:45 blofecn2 nfsserver(nfs_daemon)[3258604]: INFO: Stop: umount (1/10 attempts)
Jun  6 06:18:45 blofecn2 systemd[1]: var-lib-nfs-rpc_pipefs.mount: Deactivated successfully.
Jun  6 06:18:46 blofecn2 nfsserver(nfs_daemon)[3258604]: ERROR: Failed to unmount /var/lib/nfs
Jun  6 06:18:46 blofecn2 nfsserver(nfs_daemon)[3258604]: ERROR: Failed to unmount a bind mount
Jun  6 06:18:46 blofecn2 pacemaker-execd[7728]:  notice: nfs_daemon_stop_0[3258604] error output [ umount: /var/lib/nfs: target is busy. ]
Jun  6 06:18:46 blofecn2 pacemaker-execd[7728]:  notice: nfs_daemon_stop_0[3258604] error output [ ocf-exit-reason:Failed to unmount a bind mount ]
Jun  6 06:18:46 blofecn2 pacemaker-controld[7732]:  notice: Result of stop operation for nfs_daemon on blofecn-node2: error (Failed to unmount a bind mount) 
Jun  6 06:18:46 blofecn2 pacemaker-controld[7732]:  notice: blofecn-node2-nfs_daemon_stop_0:455 [ umount: /var/lib/nfs: target is busy.\nocf-exit-reason:Failed to unmount a bind mount\n ]

pcs resource config nfs_daemon
 Resource: nfs_daemon (class=ocf provider=heartbeat type=nfsserver)
  Attributes: nfs_no_notify=true nfs_shared_infodir=/var/lib/nfs
  Operations: monitor interval=10s timeout=20s (nfs_daemon-monitor-interval-10s)
              start interval=0s timeout=40s (nfs_daemon-start-interval-0s)
              stop interval=0s timeout=20s (nfs_daemon-stop-interval-0s)

So it seems the issue is not the bind mount. But something holding /var/lib/nfs active after the resource was started so it cannot be stopped without fencing.

How to debug that ?

Best wishes
Jacob