Migration from LXD 3 to Incus

1

Hi all, perhaps this has been asked over and over, but I could not find the right topic.

I’m currently running an old Ubuntu 18.04 with LXD 3.0.3 (ZFS storage backend) that I would like to update to newer Ubuntu. So my plan is to install Ubuntu 24.04 and Incus (and BTRFS storage backend) on a new server and then migrate from the old to the new.

When the new server is set up with Incus, can I just set it up as a remote on the old LXD instance and just do lxc copy containername new-remote:containername?
Or from the other way, set up the old server as a remote on the new and then from the new server do incus copy old-remote:containername containername?

Thanks in advance!
/Anders

2

That should be fine, though authentication works a bit differently between both releases and you’ll in general be better served by using a newer client tool, so I’d probably recommend using the incus tool to handle the copy.

I think the rough plan should be:

  1. Ensure that both source and target are listening on the network (core.https_address is set)
  2. Make sure that you have a client certificate on the target server by running incus remote generate-certificate
  3. Copy ~/.config/incus/client.crt to the source server that’s running LXD
  4. Run lxc config trust add client.crt on that system
  5. Make sure you don’t have a trust password on the old system by running lxc config unset core.trust_password
  6. Run incus remote add old-lxd IP-ADDRESS on the target Incus server
  7. Confirm that things work by doing incus list old-lxd:
  8. Try an instance copy with incus copy old-lxd:NAME local:

If you get some weird error in that last stage, try running it again with --mode=relay, but I’m not sure that LXD 3.0 supports relay mode…

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3

Wow! That’s all it takes for a live migration! This is mind-boggling to me. Thank you.

4

It’s likely that the instances are from a very old version of Ubuntu runtime, which means that there may be no more new updates, and the PHP/MySQL services are stuck to some old and unsupported 5.x version. Personally, given the choice, I’ld export any data and reinstall the services in new and fresh Incus instances.

5

Actaully the container instances are well-maintained and running newer rootfs. But when trying to upgrade the host, LXD had switched to snaps and there was many issues, I rather do one container at the time than having all the chaos at once.

6

I’ve finally gotten around to start the migration and followed your instructions @stgraber , however, on step 6 when adding the remote on the incus server I get the following error:

arune@server21:~$ incus remote add old-lxd 192.168.4.20
Error: Get "https://192.168.4.20:8443": remote error: tls: handshake failure

Could the old LXD be too old?

7

Solved “remote error: tls: handshake failure” when adding the remote by having the INCUS_INSECURE_TLS set to true.

But the last two steps did not work well.

arune@server21:~$ incus list old-lxd:
Error: The server is missing the required "api_filtering" API extension

arune@server21:~$ incus copy old-lxd:xwiki local:
Error: not found

Should I install a machine with 20.04 and whatever version of LXD that comes with it, migrate here and then to incus?

8

I did manually export a container:

lxc snapshot CONTAINERNAME snapshot-for-migration
lxc publish CONTAINERNAME/snapshot-for-migration --alias migration-image
lxc image export migration-image /tmp/container-migration

This created an image /tmp/container-migration.tar.gz which I SCPed to the new server and imported like this:

incus image import container-migration.tar.gz --alias CONTAINERNAME-import
incus launch CONTAINERNAME-import CONTAINERNAME

Not great but ok :slight_smile:

9

Thanks for sharing the steps. Question - Will the container retain its original IP address after migration ?

10

@Student No. Maybe possible, but not by default.

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