In a LXD container managed by a snap installed lxd, I see errors trying to unmount an old core snap when upgrading to 2.31.
On my host
host$ snap version
snap 2.31.1+17.10
snapd 2.31.1+17.10
series 16
ubuntu 17.10
kernel 4.13.0-36-generic
host$ snap list lxd
Name Version Rev Developer Notes
lxd 2.21 5866 canonical -
I then have an Ubuntu 16.04 LXD container, running snapd 2.30 (since 2.31 is blocked due to this bug):
container$ snap version
snap 2.30
snapd 2.30
series 16
ubuntu 16.04
kernel 4.13.0-36-generic
We can see that an update to core is still in progress, and another snap fails to refresh (which is where I noticed the problem)…
container$ snap changes
ID Status Spawn Ready Summary
72 Doing 2018-02-19T13:38:52Z - Auto-refresh snap "core"
73 Error 2018-02-22T09:43:47Z 2018-02-22T09:44:07Z Refresh "REDACTED" snap from "edge" channel
container$ snap change 72
Status Spawn Ready Summary
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:52Z Ensure prerequisites for "core" are available
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:56Z Download snap "core" (3887) from channel "stable"
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:56Z Fetch and check assertions for snap "core" (3887)
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:56Z Mount snap "core" (3887)
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:56Z Run pre-refresh hook of "core" snap if present
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:56Z Stop snap "core" services
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:56Z Remove aliases for snap "core"
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:56Z Make current revision for snap "core" unavailable
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:56Z Copy snap "core" data
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:57Z Setup snap "core" (3887) security profiles
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:57Z Make snap "core" (3887) available to the system
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:58Z Setup snap "core" (3887) security profiles (phase 2)
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:58Z Set automatic aliases for snap "core"
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:58Z Setup snap "core" aliases
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:58Z Run post-refresh hook of "core" snap if present
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:58Z Start snap "core" (3887) services
Done 2018-02-19T13:38:52Z 2018-02-19T13:38:58Z Remove data for snap "core" (3440)
Doing 2018-02-19T13:38:52Z - Remove snap "core" (3440) from the system
Do 2018-02-19T13:38:52Z - Clean up "core" (3887) install
Do 2018-02-19T13:38:52Z - Run configure hook of "core" snap if present
......................................................................
Make snap "core" (3887) available to the system
2018-02-19T13:38:57Z INFO Requested daemon restart.
......................................................................
Remove snap "core" (3440) from the system
2018-02-22T09:30:17Z ERROR cannot remove snap file "core", will retry in 3 mins: umount: /snap/core/3440: not mounted
2018-02-22T09:33:17Z ERROR cannot remove snap file "core", will retry in 3 mins: umount: /snap/core/3440: not mounted
2018-02-22T09:36:17Z ERROR cannot remove snap file "core", will retry in 3 mins: umount: /snap/core/3440: not mounted
2018-02-22T09:39:17Z ERROR cannot remove snap file "core", will retry in 3 mins: umount: /snap/core/3440: not mounted
2018-02-22T09:42:17Z ERROR cannot remove snap file "core", will retry in 3 mins: umount: /snap/core/3440: not mounted
2018-02-22T09:45:17Z ERROR cannot remove snap file "core", will retry in 3 mins: umount: /snap/core/3440: not mounted
2018-02-22T09:48:17Z ERROR cannot remove snap file "core", will retry in 3 mins: [stop snap-core-3440.mount] failed with exit status 1: Job for snap-core-3440.mount failed. See "systemctl status snap-core-3440.mount" and "journalctl -xe" for details.
2018-02-22T09:51:17Z ERROR cannot remove snap file "core", will retry in 3 mins: umount: /snap/core/3440: not mounted
2018-02-22T09:54:17Z ERROR cannot remove snap file "core", will retry in 3 mins: [stop snap-core-3440.mount] failed with exit status 1: Job for snap-core-3440.mount failed. See "systemctl status snap-core-3440.mount" and "journalctl -xe" for details.
2018-02-22T09:57:17Z ERROR cannot remove snap file "core", will retry in 3 mins: umount: /snap/core/3440: not mounted
The journal entry for the mount unit is at https://paste.ubuntu.com/p/fSFnmZFGP9/