Posts Tagged ‘clu’

Redhat Cluster NFS client service – things to notice

Friday, January 16th, 2009

I encountered an interesting bug/feature of RHCS on RHEL4.

A snip of my configuration looks like this:

<resources>
    <fs device="/dev/mapper/mpath6p1" force_fsck="1" force_umount="1" fstype="ext3" name="share_prd" mountpint="/share_prd" options="" self_fence="0" fsid="02001"/>
    <nfsexport name="nfs export4"/>
    <nfsclient name="all ro" target="192.168.0.0/255.255.255.0" options="ro,no_root_sqush,sync"/>
    <nfsclient name="app1" target="app1" options="rw,no_root_squash,sync"/>
</resources>

<service autostart="1" domain="prd" name="prd" nfslock="1">
    <fs ref="share_prd">
       <nfsexport ref="nfs export 4">
          <nfsclient ref="all ro"/>
          <nfsclient ref="app1"/>
       </nfsexport>
    </fs>
</service>

This setup was working just fine, until a glitch in the DNS occurred.This glitch resulted in inability to resolve names (which were not present inside /etc/hosts at this time), and lead to a failover with the following error:

clurgmgrd: [7941]: <err> nfsclient:app1 is missing!

All range-based nfsclient agents seemed to function correctly. I could manage to look into it only a while later (after setting simple range-based allow-all access), and through some googling, I found out this explanation – it was a change of how the agent responds to “status” command.

I should have looked inside /var/lib/nfs/etab and see that app1 server appeared with its full name. I changed the resource settings to reflect it:

<nfsclient name="app1" target="app1.mydomain.org" options="rw,no_root_squash,sync"/>

and it seems to work just fine now.