Comment 6 for bug 1576692

I cannot see failed containers in your cloud instance, nor reproduce the failure by starting new ones.

I have also created and run http://people.canonical.com/~pitti/tmp/psql-idle.sh on my laptop and your cloud instance for 40 iterations, and I couldn't reproduce a failure. This takes cloud-init out of the equation and just tests running apt install postgresq in a Type=idle unit (plus some glue around it to wait for booting and iterate). So I'm fairly sure that this approach works in principle -- but of course with more moving parts there's more that can go wrong.