Per-VM CPU & RAM allocation?

Sean McGinnis sean.mcginnis at
Fri Jan 4 20:03:00 UTC 2019

On Fri, Jan 04, 2019 at 02:45:43PM -0500, Ken D'Ambrosio wrote:
> Hi!  If I go into the UI, I can easily see how much each VM is allocated for
> RAM and CPU.  However, I've googled until I'm blue in the face, and can't
> seem to see a way -- either through CLI or API -- to get that info.  "nova
> limits --tenant <foo>" SEEMS like it should... except (at least on my Juno
> cloud), the "used" column is either full of zeros or dashes.  Clearly, if
> it's in the UI, it's possible... somehow.  But it seemed like it might be
> easier to ask the list than go down the rabbit hole of tcp captures.
> Any ideas?
> Thanks!
> -Ken
> P.S.  Not interested in CPU-hours/usage -- I'm just looking for how much is
> actually allocated.

Hey Ken,

Those values are set based on the flavor that is chosen when creating the
instance. You can get that information of a running instance by:

    openstack server show <instance_name_or_id>

And looking at the flavor of the instance. I believe it's in the format of
" (id)".

You can then do:

    openstack flavor show <flavor_name_or_id>

or just:

    openstack flavor list

to get the RAM and VCPUs values defined for that flavor.

There are corresponding API calls you can make. Add "--debug" to those CLI
calls to get the debug output that shows curl examples of the REST APIs being

Hope that helps.


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