Kerberized NFS (GSS-API) problem with multiple-IP Address and single hostname

[Frank Cusack]

On 1/4/11 3:12 AM +0000 sandeep patil wrote:
> I have kerberized NFS server running on 3 separate machine (exporting the
> same share) where ever machine has a different IP address but the same
> hostname (In other words the hostname is associated with 3 IP-address-
> for general load balancing using DNS).
...
> So my question is,how can such a scenario be tackled?

I'm surprised that this works even without Kerberos.  File locking
wouldn't work correctly, for example.

The typical way to handle this is with the automounter.  With automounted
NFS filesystems,  you can specify multiple NFS servers per mount, and
the client picks one and sticks with it.

That doesn't quite give you HA but it's close.

Another way would be to put a stateless load balancer in front of
the NFS servers.  Or instead of a load balancer it could be a load
balanced DNS server (gives only a single IP address but a different
one per client).

The most expensive way but also the only truly HA method is to use true
clustering for your NFS servers.  Since you have 3 and not just 2 servers,I 
guess you are trying to scale as opposed to going for HA.  I don't
know of any 3-way or greater clustering solutions for NFS, but you
could easily roll your own since you already have a clustered filesystem
(the hard part).

Another option is to use a different filesystem, e.g. AFS.