[ClusterLabs] NFS mount fails to stop if NFS server is lost

[Andrei Borzenkov]

On 11.04.2023 17:35, Miro Igov wrote:
> Hello,
> 
> I have a node nas-sync-test1 with NFS server and NFS export running and
> another node intranet-test1 with data_1 fs mount:
> 
>   
> 
> primitive data_1 Filesystem \
> 
>          params device="nas-sync-test1:/home/pharmya/NAS" fstype=nfs
> options=v4 directory="/data/synology/pharmya_office/NAS_Sync/NAS" \
> 
>          op monitor interval=10s
> 
>   
> 
> Disconnecting nas-sync-test1 from the network shows it's state as UNCLEAN
> and pacemaker fences it.
> 
> Then it tries to stop data_1 but it shows timeout error.
> 
>   
> 
> I know unmounting of NFS mount  when NFS server is gone requires force. Is
> there such option in Filesystem RA ?
> 

It does it unconditionally from the very beginning

                 # For networked filesystems, there's merit in trying -f:
                 case "$FSTYPE" in
                 nfs4|nfs|efs|cifs|smbfs) umount_force="-f" ;;
                 esac

But IIRC it is not enough (at least, not always) - so the trick is to 
setup the same IP address as server had. It could be an alias on a local 
client interface, does not matter. I suppose client gets stuck somewhere 
below application layer and having IP resets TCP connection allowing it 
to proceed.

I certainly had to do it in the past, and simple "umount -f" did not work.