instance-state and state in status

[Clint Byrum]

Excerpts from Kapil Thangavelu's message of Tue Mar 06 22:05:47 -0800 2012:
> Excerpts from Gustavo Niemeyer's message of 2012-03-06 21:44:10 -0500:
> > I was just having a look at the output of juju status, and the
> > relation between state and instance-state is feeling a bit awkward:
> > 
> > machines:
> >   0:
> >     dns-name: ec2-174-129-60-194.compute-1.amazonaws.com
> >     instance-id: i-d7e63cb3
> >     instance-state: running
> >     state: not-started
> > 
> > This is on a working environment. We have machine "0" in a running
> > instance-state, yet in a not-started state, which is.. hmm.. weird.
> > 
> > William, Kapil, do you recall what's the background for the new field?
> >  It sounds like the flag is about the machine agent, which still makes
> > the above output a bit confusing unless you understand the depth of
> > how juju works. Maybe the field should be named "machine-agent"
> > instead of "state"?
> 
> 
> As i recall it was a feature request from orchestra usage, to get better 
> visibility into the instance state distinct from the agent to have better 
> introspection into initial setup or orchestra problems. Its useful 
> information/feedback imo, if its confusing we can restrict its display to 
> verbose flag usage or change the keys.
> 

Its super useful, in debugging transient failures such as Ubuntu mirror
problems to be able to see that EC2 has started the machine, but the agent
has not checked in yet. The word 'state' however is really way too vague.

I'd support a change to 'agent-state' or 'machine-agent'. Those make it
quite obvious what is being reported.

It needs to be done before Ubuntu 12.04 though, otherwise this becomes
an incompatible change for anybody who has integrated with juju and
expects it to be called 'state'.