On Tue, 2014-04-08 at 15:44 -0700, Frank Filz wrote: > > On Tue, 2014-04-08 at 10:39 -0700, Frank Filz wrote: > > > > > If you mount by IP do you really care about krb5 ? Probably not, > > > > > maybe that's a clue we should not even try ... > > > > > > > > > > > > > It's certainly possible that someone passes in an IP address but > > > > then says > > > "-o > > > > sec=krb5". It has worked in the past, so it's hard to know whether > > > > and how many people actually depend on it. > > > > > > Mount by ip is sometimes used with clustered servers, especially when > > > they have all their IP addresses in the DNS record. Even using a FQDN > > > that just specifies that one IP address probably won't work then > > > (since it probably is NOT the hostname used in the server credential). > > > > I do not understand this, using an IP address or a name that resolve to said IP > > address is the same. > > But a name can resolve to a set of IP addresses, often in round-robin > fashion. It would cause havoc with NFS server on a cluster if a v3 > client had locks on 192.168.0.10 (resolved from server.mycompany.com), > and then rebooted, and resolved to 192.168.0.9 and sent SM_NOTIFY > there). At least that isn't an issue with v4... Sound you configured your DNS wrong, DNS round robin is not the right way to do load balancing for NFSv3. Also if you are specifying an IP address you can as well specify an explicit name instead, you can achieve that by using a RR CNAME and then make sure the client sticks to the resolved A name for the life of the locks. For a reboot situation you are screwed anyway unless you configure an explicit address, in which case you do not have redundancy anyway. You just use a DNS name that is resolved into a unique IP address. > Or worse, tcp connection is dropped due to inactivity, and new > connection is made to a different server node. But this could still be > an issue with v4... Same as above. > The workaround has been to specify specific IP address. The workaround to what ? Why are you using RR names if client are going to stick to a specific server anyway ? You are working around a problem you are created yourself, fix the problem! (You can fix it also by setting an entry in /etc/hosts, it is semantically identical to specifying an IP address on the mount anyway). > Now I haven't done enough with krb5 recently to know how well that > works... > I guess I'm just offering one reason IP addresses might have been > specified on mount... A bogus reason :-) Simo. -- Simo Sorce * Red Hat, Inc * New York -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
