Juju should support physical placement on OpenStack

[Tom Haddon]

As can be seen from http://paste.ubuntu.com/1200614/ "nova boot" supports a "--hint" option, which can be filtered by the scheduler to ensure instances are booted on specific underlying physical hardware. We'd need this to ensure, for instance, that all the application servers for a given service don't end up on the same physical server, and leave us with a hardware SPOF.

[Kapil Thangavelu (hazmat)]

we can model it as a constraint, as long as its not associating machine
identity directly. ie. juju deploy --constraints="distinct=true", but if
its direct targeting of a single piece of hardware that's kinda of broken
within the juju mindset, as it becomes hard for us to expand a service
(great evidence of brokenness of such in the maas-name constraint).

-k

On Wed, Sep 12, 2012 at 10:17 AM, Tom Haddon <email address hidden>wrote:

> Public bug reported:
>
> As can be seen from http://paste.ubuntu.com/1200614/ "nova boot"
> supports a "--hint" option, which can be filtered by the scheduler to
> ensure instances are booted on specific underlying physical hardware.
> We'd need this to ensure, for instance, that all the application servers
> for a given service don't end up on the same physical server, and leave
> us with a hardware SPOF.
>
> ** Affects: juju
> Importance: Undecided
> Status: New
>
> --
> You received this bug notification because you are subscribed to juju.
> https://bugs.launchpad.net/bugs/1049858
>
> Title:
> Juju should support physical placement on OpenStack
>
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>

[Martin Packman (gz)]

I've landed a fix for this on trunk, it would be great if it could get some testing in a real scenario to see if it works for you guys, before documenting and a release.

The form currently takes a json dict, which isn't pretty but avoids an extra mini language and it's
    juju set-constraint 'os-scheduler-hints={"different_host":"<some-server-uuid-here>"}'
Note that tyoping your hint key will lead to it being silently ignored, so watch underscore versus hyphen and such.