On Tue, 2016-04-05 at 09:18 -0400, Jeff Mahoney wrote: > On 4/4/16 11:12 PM, Ian Kent wrote: > > On Mon, 2016-04-04 at 20:55 -0400, Jeff Mahoney wrote: > > > Hi all - > > > > > > I'm investigating an issue where our user updated from SLE11 to > > > SLE12 > > > and the hostname for autofs mounts stopped appearing in the > > > 'mount' > > > output. I know why this happens, what the reason for it being > > > this > > > way > > > is, and that it can be overridden by setting the > > > use_hostname_for_mounts=yes option (and the side effects). Before > > > I > > > go > > > and write up the patch implementing it, is there a reason why > > > autofs > > > doesn't pass the hostname in the mount source and specify the ip > > > address > > > using the -oaddr=<ipaddr> option? Was this tried and found to be > > > wanting somehow? > > > > TBH I didn't even consider doing that. > > > > But the daemon needs to be conservative in the options it uses > > because > > maps may be used with other platforms and unknown or non-standard > > options can cause mount failures. > > > > While Linux mount.nfs(8) has the sloppy option (which maintainers > > seem > > to try and remove from time to time) other platforms probably don't. > > > > The addr=<address> option isn't listed as a valid option in nfs(5) > > and > > neither is it listed in on-line Solaris documentation that I could > > find > > so I'm not sure making the daemon use it is a good idea. > > > > Maybe there's another way... > > > > Note that I do need to be able to mount to a specific IP address > > while > > specifying the host name in the mount command but don't know of a > > way todo it. > > After looking at it again, the kernel supports doing this but nfs > -utils > explicitly doesn't. > > A closer look at nfs-utils also shows that, given a hostname, > mount.nfs > will iterate over all available addresses matching the specification > (e.g. constrained by proto=) and try to mount using each one. It will > properly pass an addr= field to the kernel but it ignores the one > passed > on the mount command line. It will use getaddrinfo() to get the list > of > addresses for the remote host and then iterate over them, retrying > until > it finds one that works. So that part of it works, but the > prioritization implemented by the replicated modules isn't. I wonder > if > it would make sense to move that to nfs-utils instead. It seems like > it > would be generally useful. I'm not sure that's a good idea. The syntax that would need to be supported by nfs-utils for this is used by OSes that provide read-only replicated mount fail over. So, as soon as that was added people will assume the Linux kernel NFS client has this fail over support which it hasn't. Ian -- To unsubscribe from this list: send the line "unsubscribe autofs" in
