juju lxd provider creates juju-zfs storage pool in lxd

[Mario Splivalo]

Each time I bootstrap an environment on a local LXD provider, a juju-zfs pool gets created:

mario@BUNTOR ~> lxc storage list
+------+-------------+--------+--------+---------+
| NAME | DESCRIPTION | DRIVER | SOURCE | USED BY |
+------+-------------+--------+--------+---------+
| lxds | | zfs | lxds | 18 |
+------+-------------+--------+--------+---------+

mario@BUNTOR ~> juju bootstrap localhost local-two
Creating Juju controller "local-two" on localhost/localhost
Looking for packaged Juju agent version 2.6.2 for amd64
To configure your system to better support LXD containers, please see: https://github.com/lxc/lxd/blob/master/doc/production-setup.md
Launching controller instance(s) on localhost/localhost...
 - juju-0761c3-0 (arch=amd64)
Installing Juju agent on bootstrap instance
Fetching Juju GUI 2.14.0
Waiting for address
Attempting to connect to 10.4.133.10:22
Connected to 10.4.133.10
Running machine configuration script...
Bootstrap agent now started
Contacting Juju controller at 10.4.133.10 to verify accessibility...

Bootstrap complete, controller "local-two" now is available
Controller machines are in the "controller" model
Initial model "default" added
mario@BUNTOR ~> lxc storage list
+----------+-------------+--------+---------------------------------+---------+
| NAME | DESCRIPTION | DRIVER | SOURCE | USED BY |
+----------+-------------+--------+---------------------------------+---------+
| juju-zfs | | zfs | /var/lib/lxd/disks/juju-zfs.img | 0 |
+----------+-------------+--------+---------------------------------+---------+
| lxds | | zfs | lxds | 19 |
+----------+-------------+--------+---------------------------------+---------+
mario@BUNTOR ~>

Why is this? juju-zfs is not even used, as the bootstrap node, in the above case, is stored on my separate zpool called lxds:

root@BUNTOR ~> zpool list
NAME SIZE ALLOC FREE EXPANDSZ FRAG CAP DEDUP HEALTH ALTROOT
juju-zfs 41.8G 330K 41.7G - 0% 0% 1.00x ONLINE -
lxds 149G 36.5G 113G - 46% 24% 1.00x ONLINE -
root@BUNTOR ~>

Is there a way to make juju not create not needed zfs pools? Why is juju even creating this pool?

[Ian Booth (wallyworld)]

The zfs (and btrfs if available) pools are created so that they may be used by charms that require storage. It's like having EBS volumes available on EC2 for instance. There's not currently any way to stop the creation as Juju's deployment model requires that any storage pools be available up front.

[Mario Splivalo (mariosplivalo)]

Hm, but I do have the 'default' pool created in lxd, which juju is happy to use. Is my naming of the pools what's confusing juju here (I named my only storage pool as 'lxds').

[John A Meinel (jameinel)]

It is unclear to me what a resolution of this bug would be, so I'm flagging it as incomplete. It may be that we want a way to set what storage pool to use? (provider config?)

[Mario Splivalo (mariosplivalo)]

Hi, John.

I would expect juju not to create additional pools, nor to create filesystems on top of existing filesystems. If I have a btrfs filesystem and want to use it, I'll put my containers on btrfs and lxd would use all the fancy features of it. Same goes for LXD.

Currently I have two storage pools in LXD, which I never wanted, but juju creates them:

mario@BUNTOR ~> lxc storage list
+----------+-------------+--------+---------------------------------+---------+
| NAME | DESCRIPTION | DRIVER | SOURCE | USED BY |
+----------+-------------+--------+---------------------------------+---------+
| juju-zfs | | zfs | /var/lib/lxd/disks/juju-zfs.img | 0 |
+----------+-------------+--------+---------------------------------+---------+
| lxds | | zfs | lxds | 10 |
+----------+-------------+--------+---------------------------------+---------+
mario@BUNTOR ~>

So, I'd say resolution of the bug would be so that juju doesn't create the juju-zfs storage pool. Yes, if I want juju to use additional storage pool (as some charm might need them, as Ian explained), yes, an config option in juju to specify those would be even better.

My main complain here is that juju is messing with my system in ways that I don't want to.

[Richard Harding (rharding)]

Also note duplicate bug pulled in where we setup zfs (or try to) when zfs isn't available.

[Canonical Juju QA Bot (juju-qa-bot)]

This bug has not been updated in 2 years, so we're marking it Low importance. If you believe this is incorrect, please update the importance.