2.1.1 treat errors correctly 1656326

[jameinel]

Description of change

The code around setting up network interfaces for a container had a statement of "if err != nil { // its not fatal, fallback to the local bridge". Which I really wanted to get rid of. However, the last time I did that, it turned out to break deployments.

This, in turn, turned out to be 2 more bugs:

• On Trusty machines, container_initialization is installing the 'lxd' package, which creates the 'lxdbr0' bridge. Before that point, we don't have the bridge in the machine inventory, so it isn't listed as a possible bridge to use. So we need to do a SetHostMachineNetworkConfig() call after calling container.Initialize.
• We had a bug in Provisioner.SetObservedNetworkConfig(), in that it is a different copy of the same code used by the Machiner.SetObservedNetworkConfig(). In Juju 2.1 I had fixed the latter one to allow recording machine devices even when we don't have Provider information. However, I didn't fix this one, because I didn't know about it. (I filed https://bugs.launchpad.net/juju/+bug/1669397 about fixing that in a more permanent way.)

There is a bunch of other cleanups and logging tweaks that were helpful while debugging all of this.

QA steps

 $ juju bootstrap aws/gce/azure
 $ juju deploy cloud-city/repository/scale2-lxd.yaml

That should create 2 trusty machines, and on the second one create 2 containers. They should be bridged onto lxdbr0. This is the same behavior as before with 2.1, but it is being done via a different code path. You should be able to see in juju debug-log that we are consciously selecting lxdbr0 for the containers. Rather than a line like: failed to prepare container 1/lxd/0 network config

Documentation changes

Ideally this isn't user facing. Other than decreasing the number of times people end up with a container that can't be accessed. Instead errors that we would have suppressed should show up as container provisioning errors.

Bug reference

lp:1656326

[jameinel]

$$merge$$

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju

[jujubot]

Build failed: Tests failed
build url: http://juju-ci.vapour.ws:8080/job/github-merge-juju/10404

[jameinel]

$$merge$$ failure appears to be Windows "could not find mongo" failures.

[jujubot]

Status: merge request accepted. Url: http://juju-ci.vapour.ws:8080/job/github-merge-juju