[lxc-users] Moving files to a guest fs from the host

Stéphane Graber stgraber at ubuntu.com
Thu Apr 4 21:37:26 UTC 2019


That error is pointing to a problem, the directory should be empty when
this isn't mounted, if it's got stuff, then that stuff is not actually
in the container rootfs.

On Thu, Apr 04, 2019 at 05:30:16PM -0400, Brandon Whaley wrote:
> Thank you for taking a look.  I was able to rsync and confirm that
> everything worked as expected if I leave the instance running in
> privileged mode during the rsync.  I was wondering if you could
> elaborate on the zfs mount option.  When I try to mount it via `zfs
> mount default/containers/instance-00000019` I get the following error:
> 
> root at atl-comp1:~# zfs mount default/containers/instance-00000019
> cannot mount '/var/lib/lxd/storage-pools/default/containers/instance-00000019':
> directory is not empty
> 
> I would of course prefer to not have the guest running during this xfer.
> 
> On Thu, Apr 4, 2019 at 12:50 PM Stéphane Graber <stgraber at ubuntu.com> wrote:
> >
> > LXD only mounts the ZFS datasets when the container is started, so you should:
> >  - Set security.privileged to true
> >  - Start the container (or alternatively manually "zfs mount" it)
> >  - Rsync
> >  - Stop or unmount the container
> >  - Unset security.privileged
> >  - Start it
> >
> > On Thu, Apr 04, 2019 at 10:42:38AM -0400, Brandon Whaley wrote:
> > > I'm in the middle of migrating some users from VZ to LXC/LXD with ZFS
> > > backed guest fs.  I'm using rsync with --numeric-ids to copy the files
> > > with the correct uid/gid to the container's private area.  It was
> > > suggested to me that I could get the uid/gid remapping done by making
> > > the destination container privileged and starting/stopping it before
> > > the xfer, which does appear to work from the host side.  Unfortunately
> > > after setting the container back to unprivileged mode and starting it,
> > > the new files are gone and the fs is back to its pre-rsync state.
> > > Setting the container to privileged mode again shows that the files
> > > are still there, just being hidden by some overlay.
> > >
> > > I'm wondering if there is a mechanism to mount a non-uid/gid remapped
> > > guest fs that will not end up being overridden when the remapping is
> > > done.
> > >
> > > root at atl-comp1:~# lxc config set instance-00000019 security.privileged false
> > > root at atl-comp1:~# lxc start instance-00000019
> > > root at atl-comp1:~# ls -hal
> > > /var/lib/lxd/storage-pools/default/containers/instance-00000019/rootfs/etc/redhat-release
> > > ls: cannot access
> > > '/var/lib/lxd/storage-pools/default/containers/instance-00000019/rootfs/etc/redhat-release':
> > > No such file or directory
> > > root at atl-comp1:~# lxc stop instance-00000019
> > > root at atl-comp1:~# lxc config set instance-00000019 security.privileged true
> > > root at atl-comp1:~# lxc start instance-00000019
> > > root at atl-comp1:~# ls -hal
> > > /var/lib/lxd/storage-pools/default/containers/instance-00000019/rootfs/etc/redhat-release
> > > ls: cannot access
> > > '/var/lib/lxd/storage-pools/default/containers/instance-00000019/rootfs/etc/redhat-release':
> > > No such file or directory
> > > root at atl-comp1:~# lxc stop instance-00000019
> > > root at atl-comp1:~# ls -hal
> > > /var/lib/lxd/storage-pools/default/containers/instance-00000019/rootfs/etc/redhat-release
> > > lrwxrwxrwx 1 root root 14 Apr  3 12:53
> > > /var/lib/lxd/storage-pools/default/containers/instance-00000019/rootfs/etc/redhat-release
> > > -> centos-release
> > > _______________________________________________
> > > lxc-users mailing list
> > > lxc-users at lists.linuxcontainers.org
> > > http://lists.linuxcontainers.org/listinfo/lxc-users
> >
> > --
> > Stéphane Graber
> > Ubuntu developer
> > http://www.ubuntu.com
> > _______________________________________________
> > lxc-users mailing list
> > lxc-users at lists.linuxcontainers.org
> > http://lists.linuxcontainers.org/listinfo/lxc-users
> _______________________________________________
> lxc-users mailing list
> lxc-users at lists.linuxcontainers.org
> http://lists.linuxcontainers.org/listinfo/lxc-users

-- 
Stéphane Graber
Ubuntu developer
http://www.ubuntu.com
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