On 17 November 2014 07:13, Ian Booth <ian.bo...@canonical.com> wrote:

> The new Juju Status work planned for this cycle will hopefully address the 
> main
> concern about knowing when a deployed charm is fully ready to do the work for
> which it was installed. ie the current situation whereby a unit is marked as
> Started but it not ready. Charms are able to mark themselves as Busy and also
> set a status message to indicate they are churning and not ready to run. 
> Charms
> can also indicate that they are Blocked and require manual intervention (eg a
> service needs a database and no relation has been established yet to provide 
> the
> database), or Waiting (the database on which the service relies is busy but 
> will
> resolve automatically when the database is available again).

As long as the 'ready' state is managed by juju and not the unit, I'll
stand happily corrected :-) The focus I'd seen had been on the unit
declaring its own status, and there is no way for a unit to know that
is ready because it has no way of knowing that, for example, there are
another 10 peer units being provisioned that will need to be related.


> So although there are not currently plans to show the number of running hooks 
> in
> the first phase of this work, mechanisms are being provided to allow charm
> authors to better communicate the state of their charms to give much clearer 
> and
> more accurate feedback as to 1) when a charm is fully ready to do work, 2) if 
> a
> charm is not ready to do work, why not.

A charm declaring itself ready is part of the picture. What is more
important is when the system is ready. You don't want to start pumping
requests through your 'ready' webserver, only to have it torn away as
a new block device is mounted on your database when its storage-joined
hook is invoked and returned to 'ready' state again once the
storage-changed hook has completed successfully.

-- 
Stuart Bishop <stuart.bis...@canonical.com>

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