Cannot mount /dev/pts error when trying to run snaps inside containers

Incus
1

Hi all! I’ve just installed Incus 6.2 for testing on an Ubuntu 24.04 server and I’m facing the following error when trying to run snaps inside a container:

pachulo@server:~$ incus launch images:ubuntu/24.04 test-snaps
pachulo@server:~$ incus exec test-snaps -- su --login ubuntu
ubuntu@test-snaps:~$ sudo apt install snapd
ubuntu@test-snaps:~$ sudo snap install hello-world
ubuntu@test-snaps:~$ hello-world
cannot perform operation: mount -t devpts --make-slave --make-private -o acl,relatime,kernmount,iversion,active,nouser,0xffffffff00000000 devpts /dev/pts: Permission denied

What am I doing wrong?

Thanks!

2

Hmm, try security.nesting=true on the container, that will most likely sort that one out.
Not sure why snapd started messing with devpts in that way.

3

It did the trick, thanks a lot!

I will ask on their forums, to try to understand why is now needed.

4

Hello,
I agree with your answer.

5

Note that we’ve got Allow devpts mounts by stgraber · Pull Request #977 · lxc/incus · GitHub which will be in Incus 6.3 and may help with this too. Apparently AppArmor on Ubuntu 24.04 started flagging things that didn’t use to be flagged.

6

I just wanted to confirm that with the Incus update to 6.3, snaps now work on containers without security.nesting=true! Thanks a lot @stgraber !

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