Comment 7 for bug 1727355

For SRU purposes, you can verify this changed against juju via the following:

juju bootstrap --debug lxd (or any provider you wish)

Confirm the following from the output:

1. Bootstrap completes successfully
2. Agent is used from stream
Look for something similar to:
juju.environs.bootstrap bootstrap.go:621 picked bootstrap agent binary version: 2.2.5
Fetching agent: curl -sSfw 'tools from %{url_effective} downloaded: HTTP %{http_code}; time %{time_total}s; size %{size_download} bytes; speed %{speed_download} bytes/s ' --retry 10 -o $bin/tools.tar.gz <[https://streams.canonical.com/juju/tools/agent/2.2.5/juju-2.2.5-ubuntu-amd64.tgz]>

We don't want to see
juju.cmd.juju.commands bootstrap.go:496 failed to bootstrap model: no matching agent binaries available

or a note about juju uploading it's own agent.

3. default-series in metadata is xenial
Look for default-series in the config map. All options will be listed, but default-series is among them.
juju.cmd.juju.commands bootstrap.go:988 preparing controller with config: map[....image-metadata-url: ... default-series:xenial ...]