Shutdown problem after upgrading to lxd 3.18

Hi,

got a container running well until lxd is upgraded to 3.18, it has problem in shutting down, help please, in the log:

Blockquote

t=2019-11-11T20:15:35+0800 lvl=info msg=“Asked to shutdown by API, shutting down containers”
t=2019-11-11T20:15:35+0800 lvl=info msg=“Shutting down container” action=shutdown created=2019-03-14T15:02:33+0800 ephemeral=false name=container1 project=default timeout=30s used=2019-11-11T06:58:02+0800
t=2019-11-11T20:15:35+0800 lvl=warn msg=“Unable to update backup.yaml at this time” name=enormous-python rootfs=/var/snap/lxd/common/lxd/containers/enormous-python/rootfs
t=2019-11-11T20:15:35+0800 lvl=info msg=“Shutting down container” action=shutdown created=2019-03-14T14:54:11+0800 ephemeral=false name=fb15 project=default timeout=30s used=2019-11-11T06:58:03+0800
t=2019-11-11T20:15:35+0800 lvl=info msg=“Shutting down container” action=shutdown created=2019-03-14T14:59:00+0800 ephemeral=false name=ib6 project=default timeout=30s used=2019-11-11T06:58:03+0800
t=2019-11-11T20:15:36+0800 lvl=eror msg=“Running apparmor” action=R err=“Failed to run: apparmor_parser -RWL /var/snap/lxd/common/lxd/security/apparmor/cache /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1: AppArmor parser error for /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1 in /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1 at line 1: Could not open ‘tunables/global’” output=“AppArmor parser error for /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1 in /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1 at line 1: Could not open ‘tunables/global’\n”
t=2019-11-11T20:15:36+0800 lvl=eror msg=“Failed to destroy apparmor namespace” container=container1 err=“Failed to run: apparmor_parser -RWL /var/snap/lxd/common/lxd/security/apparmor/cache /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1: AppArmor parser error for /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1 in /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1 at line 1: Could not open ‘tunables/global’”

Blockquote

This is odd, it suggests that /etc/apparmor was unavailable during shutdown somehow or some issue like that causing the apparmor error.

the containers still work so far, that error seems only at shutting down of the containers, can I just ignore those errors for now?

t=2019-11-18T07:54:27+0800 lvl=eror msg=“Failed to destroy apparmor namespace” container=container1 err=“Failed to run: apparmor_parser -RWL /var/snap/lxd/common/lxd/security/apparmor/cache /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1: AppArmor parser error for /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1 in /var/snap/lxd/common/lxd/security/apparmor/profiles/lxd-container1 at line 1: Could not open ‘tunables/global’”