How to deploy an updated charm

[Kapil Thangavelu]

Excerpts from William Reade's message of 2012-05-13 22:52:18 -0700:
> On Sun, 2012-05-13 at 22:39 -0700, Haitao Jiang wrote:
> > I tried upgrade-charm, but it requires that service to be up and
> > running (started state).
> 
> In this situation, you should be able to use `juju upgrade-charm
> --force ...`; this will upgrade the deployed charm regardless of state
> (but will not run the upgrade hook, which requires the "started" state).

There are also tools to allow you to manually resolve errors in service units 
via juju resolved (optionally with --retry flag). This is expected to be done 
after an administrator has manually corrected the error on the unit, and is 
used to denote to juju that things are now working correctly. After the service 
units are in a good state, the upgrade can be completed without the force flag. 

One important distinction is that upgrade with a  force flag avoids execution of 
the upgrade-charm hook as the hook cant make any assumptions/reasoning about 
state when upgrade is being performed against a potentially arbitrary error state.

cheers,

Kapil