Open Stack

Vishvananda Ishaya <vishvananda at gmail.com> wrote on 01/27/2015 04:29:50 PM:

> From: Vishvananda Ishaya <vishvananda at gmail.com>
> To: "OpenStack Development Mailing List (not for usage questions)"
> <openstack-dev at lists.openstack.org>
> Date: 01/27/2015 04:32 PM
> Subject: Re: [openstack-dev] [nova] [api] Get servers with limit and
> IP address filter
>
> The network info for an instance is cached as a blob of data
> (neutron has the canonical version in most installs), so it isn’t
> particularly easy to do at the database layer. You would likely need
> a pretty complex stored procedure to do it accurately.
>
> Vish

Vish,

Thanks for the reply.

I agree with your point about the difficultly in accurately querying the
blob of data; however, IMHO, the complexity this fix does not preclude the
current behavior as being classified as a bug.

With that in mind, I was wondering if anyone in the community has any
thoughts on if the current behavior is considered a bug?

If so, how should it be resolved? A couple options that I could think of:

1. Disallow the combination of using both a limit and an IP address filter
by raising an error.
2. Workaround the problem by removing the limit from the DB query and then
manually limiting the list of servers (after manually applying the IP
address filter).
3. Break up the query so that the server UUIDs that match the IP filter are
retrieved first and then used as a UUID DB filter. As far as I can tell,
this type of solution was originally implemented but the network query was
deemed to expensive [1]. Is there a less expensive method to determine the
UUIDs (possibly querying the cached 'network_info' in the '
instance_info_caches' table)?
4. Figure out how to accurately query the blob of network info that is
cached in the nova DB and apply the IP filter at the DB layer.

[1]: https://review.openstack.org/#/c/131460/

Thanks,
Steven Kaufer

>
> On Jan 27, 2015, at 2:00 PM, Steven Kaufer <kaufer at us.ibm.com> wrote:
>
> Hello,
>
> When applying an IP address filter to a paginated servers query (eg,
> supplying servers/detail?ip=192.168&limit=100), the IP address
> filtering is only being applied against the non-filtered page of
> servers that were retrieved from the DB; see [1].
>
> I believe that the IP address filtering should be done before the
> limit is applied, returning up to <limit> servers that match the IP
> address filter.  Currently, if the servers in the page of data
> returned from the DB do not happen to match the IP address filter
> (applied in the compute API), then no servers will be returned by
> the REST API (even if there are servers that match the IP address
filter).
>
> This seems like a bug to me, shouldn't all filtering be done at the DB
layer?
>
> [1]: https://github.com/openstack/nova/blob/master/nova/compute/
> api.py#L2037-L2042
>
> Thanks,
> Steven Kaufer
>
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