Comment 2 for bug 1780694

Unclear. This deployment was a bit fraught because we didn't add the route to the tenant network until quite a few attempts by the charm to install the snap. Here's the (rather large) unit agent log: https://private-fileshare.canonical.com/~pjdc/jaas-candid.unit-prometheus-0.log.xz

For some reason /var/snap/prometheus/common also did not get created, which caused further problems. I was able to cleanly install the snap on bionic and the charm in a xenial LXD, so things are not fundamentally broken.