Images Not Being Deleted Automatically

LXD
1

Trying to get unused LXC images to be deleted on a daily basis. We have the following settings in place:

# lxc config show
config:
  images.auto_update_cached: "false"
  images.auto_update_interval: "0"
  images.remote_cache_expiry: "1"

We have no containers currently running. However, we have images showing with lxc image list that have been unused for weeks.

Example:

#lxc image info d0e84947eda4
Fingerprint: d0e84947eda42b8d258d162edf53ff7e3f05b7cd76c852e7dcbcbc88c6025b83
Size: 16273.32MB
Architecture: x86_64
Public: no
Timestamps:
    Uploaded: 2019/06/08 16:51 UTC
    Expires: never
    Last used: never
Properties:
Aliases:
Cached: no
Auto update: disabled

How do we get LXD to remove such images automatically?

2

From the doc:

The image will be kept locally as a private image until either it's been unused
(no new container spawned) for the number of days set in
`images.remote_cache_expiry` or until the image's expiry is reached
whichever comes first.

your image has never been used, so the remote_cache_expiry parameter is not relevant.

3

Looks like the ones being left with a “never” used date are snapshots created by nova-lxd. They remain even after both the instance and glance snapshot have been deleted. I don’t think they should be on compute in the first place unless I’m overlooking something.

Side note - is there a way to trigger an image cache cleanup manually?

4

Reloading lxd would cause an image expiry to trigger I believe (systemctl reload snap.lxd.daemon).

Only images that are marked as cached will be affected by auto-expiry. Use lxc image info to check.

5

Thank you. Looks like none of these are cached. If I’m not mistaken, they are either images from glance used by nova-lxd to launch containers or snapshots created by nova-lxd. Any idea if a method currently exists to clean them up on the compute node automatically? And is there a way outside of patching nova-lxd to bypass LXC’s default local snapshots and only use snapshots stored by glance? At the moment it seems to keep a local snapshot and send one to glance. If I delete the local one, restoring no longer works.

Not sure if there’s something in lxc config or profiles that would accomplish what we’re trying to do.

6

LXD itself isn’t aware nor does anything directly for nova-lxd/glance, so I think your best bet is to get nova-lxd to do what you want there. Cleaning things up behind its back is likely to result in unexpected problems.