Lxd: snap refresh make containers hangs and disconnect exec shells

Versions

Ubuntu 18.04.2 LTS \n \l
snap 2.39.3
snapd 2.39.3
series 16
ubuntu 18.04
kernel 4.15.0-48-generic
lxd: 3.15

Problem

This morning snapd make a snap refresh on lxd:

snap changes
ID Status Spawn Ready Summary
232 Done today at 09:54 CEST today at 09:54 CEST Auto-refresh snap “lxd”

This had 2 consequences:

  • all my exec shell connections (lxc exec) has been broken
  • worse: all /proc inside containers have been broken, so all containers had to be rebooted.

This indeed is incompatible with production environment.
As already said in an other topic, ops should be the only ones to decide when doing such an operation (snap refresh).

there has work been done that running snaps will not be stopped on refresh anymore … not sure where exactly this stands yet, probably @zyga-snapd or @chipaca can comment about timelines.