[Maas-devel] Node states

[Francis J. Lacoste]

Hi Matt,

Thanks for this write-up. More questions and comments below.

On 12-02-03 09:54 AM, Matthew Revell wrote:
> Hi,
> 
> Across different meetings there has been a common theme: uncertainty
> over precisely what state a node can be in and what those states mean.
> 
> Here's my understanding of the states we need:
> 
>  * Declared: MaaS is aware of the node and has assigned it a system
> ID, but has done nothing else to it. A declared node can return to
> this state.

I don't understand what 'A declared node can return to this state' means?

>  * Testing: Smoke or burn-in tests are in process.

Shouldn't we call this 'Commissioning', since all of this is part of the
Commissioning process?

>  * Bad: for a reason not covered by the sub-states, the node cannot be used.
>   - Bad -- testing: smoke or burn-in testing has a found a problem.
>   - Bad -- MIA:  the MaaS can't contact the node.
>  * Ready: Testing has been done and the node is in the general pool
> ready to be deployed.
>  * Reserved: Testing has been done and the node is ready for named deployment.
>  * Allocated: A node has been allocated to a specific user for their
> exclusive use.
>  * Deployed: The node has been deployed with either a fresh Ubuntu
> install or a Juju charm.

I think 'Allocated' is more commonly use for what we refer to as
'Deployed'. That would be worth user testing. Note also that it's not
the node that is deployed, but a workload that is 'deployed to' the node.


>  * Retired: The node has been removed from service until the MaaS
> owner overrides the retirement.
> 
> The "Allocated" state is one we've discussed but is out of scope for 12.04.
> 

I think this state kind of overlaps with 'Deployed' and 'Reserved'.
Another reason for dropping that state now, and use 'Allocated' for what
you use 'Deployed' now. Let's revisit this later when this use-case
becomes clearer.

> The "Bad" states haven't really come up in conversation but they seem
> to me to be necessary.
> 
> There is some fuzziness around "Retired": is a retired node one which
> has been taken out of action manually, for whatever reasons, or is it
> a node that was previously declared and has been torn down? From our
> discussions in Budapest, the first of these makes most sense to me.
> Also, I believe a deployed node simply becomes declared once it has
> been torn down.
> 
> Thanks in advance for your comments.
> 
> --
> Matthew Revell
> Launchpad Product Manager
> Canonical
> 
> https://launchpad.net/~matthew.revell
> 


-- 
Francis J. Lacoste
francis.lacoste at contre.com

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