[Openstack-operators] [openstack-dev] [glance] [nova] Glance bug with Kilo upgrade & Nova

Bhandaru, Malini K malini.k.bhandaru at intel.com
Tue Jun 9 07:09:54 UTC 2015

Flavio, would a DB script that writes an empty string or NOP or something instead of NULL In the column do the trick?
Then the problem degenerates to a new DB upgrade script.


-----Original Message-----
From: Flavio Percoco [mailto:flavio at redhat.com] 
Sent: Monday, June 08, 2015 11:47 PM
To: OpenStack Development Mailing List (not for usage questions)
Cc: openstack-operators at lists.openstack.org
Subject: Re: [openstack-dev] [glance] [nova] Glance bug with Kilo upgrade & Nova

On 08/06/15 11:46 -0400, Clayton O'Neill wrote:
>We tested testing Kilo upgrades in our hardware dev environments last 
>week and the second time through ran into this bug which right now is 
>probably a show-stopper for us.
>The issue here is that the v1 Glance API allows you to create images 
>with properties that are 'NULL' in the Glance database.  For example:
>    glance image-create --name cirros_test --disk-format qcow2 
>--container-format bare --file cirros-0.3.4-x86_64-disk.img --is-public 
>True --is-protected True --progress --property description=
>It's apparently also fairly easy to end up with a NULL description when 
>editing images properties via Horizon.
>The issue is that the v2 Glance API returns these NULL properties to 
>the client, which then validates them against the schema returned by the v2 API.
>This schema returns specifies that the description property *must* be a string.
>In the Kilo release, Nova has been changed to use the v2 API, so 
>suddenly this matters.  The net effect is that end users can pretty 
>easily create properties with NULL values, and then won't be able to boot instances using those images.
>What makes this worse is that it's completely opaque to end users, 
>since this just reports that no node was available to schedule the instance.
>However, Nova *only* uses the v2 api to list images if the 
>glance.allowed_direct_url_schemes config key is set in the config file.
>However, this config item defaults to an empty array, meaning that by 
>default it's *always* set.  There doesn't appear to be a way to unset a 
>value with oslo-config that has a default value, blocking off that 
>route to work around the issue.  Disabling the v2 Glance API we don't 
>think will work, since Nova appears to assume the v2 API is available.

AFAIK, Nova supports V2 image-lists since before Juno when the allowed_direct_url_schemes config option is set. Are you referring to another change? Has the default been changed in Nova? I'm asking because I was working on this migration to V2 and we decided to postpone it to L.

>Another work around we've looked at is to change the DB schema for 
>image properties (yuck) to not allow NULL values.  This results in 
>Glance returning a
>500 error since glance-api is attempting to insert an invalid value.  
>This is better than instances failing in an opaque fashion, but still pretty horrible.
>Has anyone else run into this issue yet?  Are there other work arounds 
>that we've not thought of other than "Don't create images with NULL properties?"
>User education is definitely an option, but given the failure mode, 
>it's not a great solution for us.

I believe this needs to be fixed in the client rather than the API and/or the schemas. I'll take a look at this right away.

Another workaround could be updateting `schema-image.json` to add the schemas that are missing and let the client download the final schema from the V2 API.

Keep an eye on the bug, patches coming your way (assuming what I have in mind will work).

Flavio Percoco

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