using snap juju led to an error on fetch-oci.service

[vidasov]

... led me to not being able to install microk8s. Except when it was installing fine but than other snaps like juju and lxd woud be missing.
Using juju from apt after fresh install was fixing error.
This time I was using lxd zfs_backend as well from apt, not snap store.

ubuntu 18.04.4 server
juju --version 2.7.6-bionic-amd64
lxd --version 3.0.3

snap list
Name Version Rev Tracking Publisher Notes
core 16-2.45 9289 latest/stable canonical✓ core
microk8s v1.18.3 1422 1.18/stable canonical✓ classic
osmclient 0+git.4ab46a0 45 latest/edge canonical✓ -