[openstack-dev] [Horizon][Nova] Editing flavor causing instance flavor display error

Sean Dague sean at dague.net
Thu Aug 3 09:59:21 UTC 2017

On 08/02/2017 10:12 PM, Zhenyu Zheng wrote:
> Hi All,
> Horizon provided the feature to allow user edit existing flavors, no
> matter it is currently used by any instances or not. While Nova doesn't
> provide this kind of ability, Horizon achieved this by deleting the old
> flavor first and create a new flavor with the requested properties. And
> the flavor ID will be changed to a new UUID.
> This causes problem when display instances with latest Nova, Horizon
> display flavor name by request flavor details using the flavor id
> returned by get_instance request, because Nova now moved flavor to
> api_db, and when a flavor got deleted, it will be directly removed from
> the DB, and when displaying, the field will be "Not Available".
> Should we stop support editing existing flavors? It is actually
> deleting-and-create.

Yes, it should not be a feature in Horizon, because it's extremely
misleading what it does. It's actually really breaking their
environment. It's unfortunate that it was implemented there at all. :(

> Maybe we should  at least add WARNING notes about  this when editing
> flavors, about how it is actually done and what kind of influence will
> be to the existing instances. 
> Nova now(> microversion 2.47) can reply embedded flavor details
> including ram, vcpus, original_name etc.
> Since we provided this flavor editing feature and we displayed "name" as
> a identifier, after we done some flavor edit, even we fix the above
> mentioned problem and displayed the correct flavor name, the flavor
> details will be different than the actual instance type.

There was an extremely long an heated discussion in the Nova room in
Atlanta about including that name in server document because of this
Horizon behavior. I came down on the side of showing it, because people
that use the flavor "rename" function are actually basically breaking
their environment (in many ways). Lots of people don't do that, so this
is useful to them so that they can create new instances like the ones there.

The only way to change the flavor of an instance is to resize it.


Sean Dague

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