Machine id option to deploy

[Tim Penhey]

On 09/04/13 09:19, Gustavo Niemeyer wrote:
> On Mon, Apr 8, 2013 at 5:09 PM, roger peppe <roger.peppe at canonical.com> wrote:
>> I feel that deploy-to is possibly a first step towards placement, which
>> I think can be seen as largely orthogonal to constraints,
>> although naturally they will interact, and we will need to decide
>> how they should do so.
> 
> Constraints are *exactly* that: a way to determine placement, and they
> are a mechanism that enables us to continue expanding in all those
> areas.

[removing the juju list and keeping this on -dev]

Hi All,

Gustavo, I'm having difficulty trying to work out what your issue is here.

Where I think we are in agreement is the following:
 * Users want to be able to place multiple units on a machine, and we
need to provide a way to do that.

Is the issue in how we define the placement?

To me, constraints are about provisioning an appropriate machine onto
which the unit will be placed.  However using a --force-machine type
parameter, the user is saying "I know better" and we should do that.

I don't see this as a way to stop a trivial add-units from working.

If we tried to enforce a unit level constraint to say "install on
machine X", then this would have more of an impact in trying to add more
units where it would try to duplicate the unit constraints.

Does this make sense?

Tim