maas-devel team mailing list archive

[Gavin Panella <gavin.panella@xxxxxxxxxxxxx>]

On 21 January 2014 13:52, Andres Rodriguez <andreserl@xxxxxxxxxxxxx> wrote:
> All,
>>
>> Pondering on what Jeff says though, should a node even get to the
>> Ready state without a power type?  Any chance we can require a power
>> type at the point of accepting a node?
>
> I personally believe that not allowing a machine to get to the Ready
> state without a power type is an inappropriate solution.

Can you explain why? I think it would be quite good to hold back nodes
until the means of power control have been specified.

I think there should not be a default power type. If it cannot be
discovered, the node is not "ready" and intervention is required.

If we need to support manual power control, that ought to be an option.
However, this opens a can of worms: how do we tell a user when we need
them to power a machine on or off? In the UI we can add a message. Via
the API we would need a new way to indicate this to caller of start().
All clients would need to grok this, including Juju and the Juju GUI.

This is not specific to power control: it's a problem with warnings in
general. They're hard to get in front of a user, and harder still to get
a user to heed them.

However... with the new driver model we're aiming for, each site could
customise their own "Manual" (or "Externally-managed") driver. One site
might send a text message, another might activate a solenoid glued to a
machine's switch. My point is that it would no longer be MAAS's problem;
the user has explicity told MAAS that it's his/her problem.

> I believe, however, that the user should be warned that there's no
> power type and that whatever stage is to be done, the node should be
> powered manually.
>
> On this note, it would also be interesting to add some kind of
> notification/status of the power state of the node if one set; that
> way, if none set, it means that the node will not be power managed and
> the user will have to do that manually.

I don't follow. Can you give an example perhaps?