[[!comment format=mdwn
 username="joey"
 subject="""comment 1"""
 date="2019-04-16T14:35:26Z"
 content="""
Info can propagate out of containers, but then it becomes Info of the Host
that the container is part of. The IsInfo type class has a propagateInfo
that controls whether a value of that type propagates from container to
host.

The ssh HostKeyInfo has a propagateInfo that prevents propagation.
This makes sense with the current data structure because the ssh host key
inside the container does not replace the host key used outside. The data
structures would need to be changed in some way to support propagation.
I guess HostKeyInfo could be changed to a map from hostname to what it
contains now.

There would be follow-on changes needed, eg Dns.genSSHFP adds the ssh host
key to a dns record, and I think it would only make sense for that to add
the host's ssh key, not one for each container.

WRT the name of a systemd container, it's not a hostname, but a systemd
machine name. Propellor does not currently track the hostname of a
container as Info (and the Info system is actually not used for hostnames
since the hostname is part of each Host). The closest thing available
currently is Propellor.Info.alias which can be used in a container to add
an CNAME to the Host that contains it.

Anyway, changing the name of a systemd container would indeed build a new
container. I'd probably revert the current property (so it deletes the
current container) and add a new property with the new name.
"""]]
