[lxc-users] root device isn't being inherited on ZFS storage pool

[Stéphane Graber]

On Wed, May 31, 2017 at 11:01:39AM -0600, Joshua Schaeffer wrote:
> I guess I should have mentioned an important change. When I switched from
> BTRFS to ZFS I also went from LXD 2.0 to 2.13.

Right and with LXD 2.8 we moved from always adding a container-local
disk device to having it be inherited from the profile, which is what's
causing the confusion here.

> 
> On Wed, May 31, 2017 at 10:27 AM, Joshua Schaeffer <jschaeffer0922 at gmail.com
> > wrote:
> 
> > I've recently switch from using BTRFS to ZFS backend, and my containers on
> > the ZFS backend aren't inheriting the root device from my default profile:
> >
> >     lxduser at raynor:~$ lxc config show fenix
> >     architecture: x86_64
> >     [snip]
> >     devices: {}
> >     ephemeral: false
> >     profiles:
> >     - default
> >     - 30_vlan_mgmt_server

They ar inheriting it but you won't see the inherited stuff unless you
pass --expanded to "lxc config show".

> > The default profile, which the container is using has the root device with
> > a pool specified:
> >
> >     lxduser at raynor:~$ lxc profile show default
> >     config: {}
> >     description: Default LXD profile
> >     devices:
> >       root:
> >         path: /
> >         pool: lxdpool
> >         type: disk
> >     name: default
> >
> > But the container isn't showing a root device (or any device for that
> > matter), and I get an error when I try to set a size limit on the root
> > device for that container:
> >
> >     lxduser at raynor:~$ lxc config device set fenix root size 50G
> >     error: The device doesn't exist

That's because it's an inherited device rather than one set at the
container level. To override the inherited device you must add a new
local device with the same name.

lxc config device add fenix root disk pool=lxdpool path=/ size=50GB

That should do the trick and will then show up in "lxc config show"
(without --expanded) since it will be a container-local device.

> > Is there a ZFS property that has to be set to get it to inherit the
> > device? I was able to successfully create the root device on another
> > container, but I don't want to create the device on each container, I just
> > want to set it on the profile. I'm on LXD 2.13. Here is my storage device:
> >
> >     lxduser at raynor:~$ lxc storage list
> >     +---------+--------+---------+---------+
> >     |  NAME   | DRIVER | SOURCE  | USED BY |
> >     +---------+--------+---------+---------+
> >     | lxdpool | zfs    | lxdpool | 15      |
> >     +---------+--------+---------+---------+
> >
> > Thanks,
> > Joshua Schaeffer


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