On Fri, Aug 07, 2015 at 03:30:41PM -0400, Ian Stakenvicius wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA256 > > On 07/08/15 03:18 PM, William Hubbs wrote: > > On Fri, Aug 07, 2015 at 01:39:25PM -0400, Ian Stakenvicius wrote: > >> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 > >> > >> On 07/08/15 12:59 PM, William Hubbs wrote: > >>> On Fri, Aug 07, 2015 at 12:10:56PM -0400, Ian Stakenvicius > >>> wrote: > >>>> -----BEGIN PGP SIGNED MESSAGE----- Hash: SHA256 > >>>> > >>>> On 07/08/15 11:30 AM, William Hubbs wrote: > >>>>> On Thu, Aug 06, 2015 at 08:07:44PM -0400, Ian Stakenvicius > >>>>> wrote: > >>>>>> > >>>>>> Can we get "nofail" immediately in the mount -a variants > >>>>>> of localmount/netmount and expand that in netmount to > >>>>>> make the nfsclient dep be a "use" or a "need" depending > >>>>>> on if it's set or not?? That would imo kill the existing > >>>>>> bug that started all of this too. > >>>>> > >>>>> Sure, I can get the nofail support in pretty quick, and I > >>>>> think that is a feature we should have. > >>>>> > >>>>> Right now, netmount is using the use dependency to make > >>>>> sure network file system utilities are started before us. > >>>>> Because of the all-or-nothing nature of netmount, we can't > >>>>> switch those dependencies to need. It would cause netmount > >>>>> to fail if one of those utilities fails to start. The use > >>>>> dependency is the best one we can use at this time, and a > >>>>> migration path was specifically laid out in the news item. > >>>>> > >>>> > >>>> My thinking here is that, unless network mounts in fstab are > >>>> listed as 'nofail', that netmount failing due to the > >>>> dependent services not being able to start would be a valid > >>>> case. Sysadmins that don't want netmount to fail no matter > >>>> what would be able to use 'nofail' to ensure that happens. > >>>> > >>>> This is of course predicated on (1) it being a good idea, > >>>> and (2) fstabinfo or whatever the check currently is that > >>>> would add nfsclient to depend() could easily swap 'use' for > >>>> 'need' based on the (lack of) existence of the nofail > >>>> attribute in fstab. > >>> > >>> The issue with using the need dependency is that netmount is > >>> not granular enough. It mounts all types of network file > >>> systems, so if we fail because nfs is a need dependency and > >>> doesn't start, no other types of network file systems that use > >>> daemons will be mounted. That's what I meant by > >>> all-or-nothing. > >>> > >>> William > >>> > >> > >> Yes I follow that. My thoughts are #1, netmount (and localmount > >> for that matter) are all-or-nothing things; so if the service > >> fails then I don't think anything can necessarily be assumed as > >> to which mounts succeeded and which don't. > > > > Yes, they are, but mount and umount -a are not. They can report > > partial failures (check the exit codes). > > > > If I switch to using need dependencies for the file system clients, > > and one fails to start, mount -a would never run, which means NO > > net-based file systems that use clients would be mounted. > > Yeah I follow that, I just don't see that as something we need to > avoid given it can be avoided on systems by keeping netmount from > failing via 'nofail' on nfs mounts in fstab (or there being no 'auto' > nfs mounts in fstab to begin with) > > If the plan is that localmount and netmount will return error and fail > when one-or-more fstab entries with 'auto' and without 'nofail' can't > be mounted, then I see it as being convenient that netmount would > mount the other filesystems, but not imperative.
That's exactly what mount -a -t ... does; it tries to mount everything of the specified types that does not have noauto in the options. If nofail is in the options for a file system, it doesn't report failure for that file system if it doesn't mount. I would rather err on the side of convenience in this case. > > (in case i wasn't clear earlier, i am talking about the 'need' vs > 'use' being dynamically chosen by the script; yes it's almost as evil > as the dynamic choices in depend() that might be necessary to do a > 'localmount' wrapper around mount.* services, but instead of it being > done for -everything- it's at least only done for one or a few corner > cases -- that being nfs mounts but there are likely others that need > daemons started at runtime) > > > > My thinking is to allow things to mount that can, but still report > > it as a failure if everything doesn't mount. > > Except for the fact that this isn't possible with a 'need' on > nfsclient, I think it's a great plan. :) Absolutely, and that is why I have issues with using "need" for file system clients like nfsclient. I see it as changing netmount's behaviour in a bad way. William
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