[Gluster-devel] Improvements in Glusterd NFS-Ganesha integration for GlusterFS3.9

[Jiffin Tony Thottan]

Hi all,

Currently all the configuration related NFS Ganesha is stored 
individually in each
node belong to ganesha cluster at /etc/ganesha.  The following are the 
files
present in it :
- ganesha.conf - configuration file for ganesha process
- ganesha-ha.conf - configuration file high availablity cluster
- files under export directory - export configuration file for gluster 
volume
- .export_added  - to track no of volumes got exported

The glusterd does not have specific control over this file or in other 
words there
is no specific way to synchronize these files. So this will result in 
having different
values for above files. For example consider following node down scenario,
  * Two volumes volA and volB got exported one after another while one of
     node(lets call it as tmp)  the ganesha cluster was down.
  * Now in current cluster volA will be export with Id = 2, for volB it 
will be 3.
  * When tmp comes up, there is a chance in which volA with id 3 and 
volB with 2
  * This a give undesired behavior during failover and failback with the 
node tmp.

More such scenarios is described in the bug[1]. A proposed solution to 
overcome
such situations is that store above mentioned configuration files in 
shared storage.
Then it can be shared by every node in ganesha cluster and all such mess 
can be
avoided. More detailed description can be found in feature page[2]

So here as prerequisite, user need to create a folder nfs-ganesha in 
shared storage
and save ganesha.conf, ganesha-ha.conf in it. When the cli "gluster 
nfs-ganesha enable"
got executed, glusterd creates a symlink in /etc/ganesha using 
ganesha.conf, then start
ganesha process and sets up HA. During disable it teardowns the HA, 
stops ganesha
process and then remove entry from /etc/ganesha.

For existing users, scripts will be provided for the smooth migration.

Please share your thoughts on the same

[1] Tracker bug : https://bugzilla.redhat.com/show_bug.cgi?id=1355956
[2] Feature page : http://review.gluster.org/#/c/15105/
[3] Patches posted upstream for share storage migration
         * http://review.gluster.org/14906
         * http://review.gluster.org/14908
         * http://review.gluster.org/14909
[4] Patches posted/merged upstream as part of clean up
         * http://review.gluster.org/15055
         * http://review.gluster.org/14871
         * http://review.gluster.org/14812
         * http://review.gluster.org/14907

Regards,
Jiffin


Regards,
Jiffin