"ERROR while obtaining model user" while executing juju run

[Michael Skalka]

As seen in this test run: https://solutions.qa.canonical.com/testruns/testRun/d0802823-0c25-44c0-bed1-ac097e0d9b1e
Using Juju 2.8.6 on Focal.

While attempting to execute juju run the command fails with:

2020-11-12-07:23:45 root DEBUG [localhost]: juju run -m foundations-maas:openstack -u ceph-mon/0 'ceph osd pool create scbench 100 100'
2020-11-12-07:23:47 root ERROR [localhost] Command failed: juju run -m foundations-maas:openstack -u ceph-mon/0 'ceph osd pool create scbench 100 100'
 DEBUG:root:vault-mysql-router is lead by vault-mysql-router/0
2020-11-12-07:23:47 root ERROR [localhost] STDOUT follows:
ERROR while obtaining model user: while obtaining model user: read tcp 127.0.0.1:43392->127.0.0.1:37017: read: connection reset by peer

2020-11-12-07:23:47 root ERROR [localhost] STDERR follows:
None

I can't find anything glaringly offending in the Juju controller logs, however in syslog the juju-db was killed but I wasn't able to find out why:

...
Nov 12 07:23:47 juju-1 systemd[1]: snap.juju-db.daemon.service: Main process exited, code=killed, status=6/ABRT
Nov 12 07:23:47 juju-1 systemd[1]: snap.juju-db.daemon.service: Failed with result 'signal'.
Nov 12 07:23:47 juju-1 systemd[1]: snap.juju-db.daemon.service: Scheduled restart job, restart counter is at 1.
Nov 12 07:23:47 juju-1 systemd[1]: Stopped Service for snap application juju-db.daemon.
Nov 12 07:23:47 juju-1 systemd[1]: Started Service for snap application juju-db.daemon.
...

Controller crashdumps here: https://oil-jenkins.canonical.com/artifacts/d0802823-0c25-44c0-bed1-ac097e0d9b1e/generated/generated/juju_maas_controller/juju-crashdump-controller-2020-11-12-07.26.38.tar.gz
Full artifacts here: https://oil-jenkins.canonical.com/artifacts/d0802823-0c25-44c0-bed1-ac097e0d9b1e/index.html

[John A Meinel (jameinel)]

We haven't been investigating this one, and it doesn't seem to have come up again. If it is an issue that is recurring, please reopen.