After upgraded multipass to 1.3.0, snapcraft cannot work any more

After upgraded multipass to 1.3.0, snapcraft cannot work any more.

$ sudo snap refresh multipass --channel stable
multipass 1.3.0 from Canonical✓ refreshed

$ snapcraft
Launching a VM.
snap "snapd" has no updates available                                           
Source path "/parent/work/btctools-snap" does not exist
An error occurred with the instance when trying to mount with 'multipass': returned exit code 1.
Ensure that 'multipass' is setup correctly and try again.

Or got this:

$ snapcraft                                   
Launching a VM.
snap "snapd" has no updates available                                           
Could not find snap/snapcraft.yaml. Are you sure you are in the right directory?
To start a new project, use `snapcraft init`
Run the same command again with --debug to shell into the environment if you wish to introspect this failure.

I noticed that multipass now be a strictly confined snap without --classic. So there seems to be a serious problem with its cooperation with snapcraft.

This will fix the issue:

sudo snap refresh multipass --candidate --classic

Version 1.2.0 with --classic will be installed. Everything looks OK.

Or if you want a reinstall:

multipass delete snapcraft-btctools
multipass purge
sudo snap remove multipass
sudo snap install multipass --candidate --classic

Update 1

I think it has something to do with my partition structure.

/parent is a mounted btrfs subvol (subvolid=0, the real rootfs), and /parent/work is also a btrfs subvol.

/ is also a btrfs subvol, it is the default subvol (so mount without subvolid will get it). And it’s real path: /parent/rootfs.

$ cat /etc/fstab
# /dev/sda2
UUID=3f0842c7-29e8-4220-93da-e3fea5b3bbcc       /               btrfs           rw,relatime,ssd,space_cache             0 0
UUID=3f0842c7-29e8-4220-93da-e3fea5b3bbcc       /parent         btrfs           rw,relatime,ssd,space_cache,subvolid=0  0 0

I think this is related to my problem because I run my own strictly confined snap (https://snapcraft.io/btctools), and as a result, I found that I couldn’t find /parent at all, just like it didn’t be mounted.

So it should be a problem of snapd instead of snapcraft?

Hi @btccom what’s your Snapcraft version? You need 4.0 to work with Multipass 1.3.0.

snapcraft --version
snapcraft, version 4.0.4

So I think this is a problem with mount points.
Strict mode lost my custom mount point.

Hey @btccom, indeed due to strict confinement we can only currently support mounts under /home. We’re working on relaxing this requirement, but in the mean time you can bind-mount (symlinking won’t be enough) your workspace to $HOME and that should work fine.

Okay, I understand. But then I switched to lxd and it works fine.