Code review comment for lp://staging/~chris.macnaughton/openstack-mojo-specs/upgrade-spec

I understand this is a WIP. Just some notes for the next revision(s).

Most (all?) juju ssh $UNIT sudo $CMD should be juju run --unit $UNIT $CMD. You get root for free and various --format output options more convenient for python.

A number of WIP print statements that either need logging statements or removal before landing. Not also the use of logging.error or logging.warn where appropriate.

The juju series-update commands, when is it safe to set this for an application that may have multiple units?

Individual try/except blocks look good. But it would make sense to have a top level try/except that determines success or failure based on raised exceptions in nested tries.

Larger question. At what point does it make more sense to create a bash script and scp it to the unit to run. Rather, than piecemeal commands over ssh? That might be a cleaner approach and it would be re-usable outside mojo.