Improve filter instances by IP performance

Improve filter instances by IP performance

https://blueprints.launchpad.net/nova/+spec/improve-filter-instances-by-ip-performance

The aim of this feature is to improve the performance when filter instances by IP address.

Problem description

Nova allows filtering instances by IP address when list instances. But the performance of such fitering is poor, this is due to that IP address is one part of the instance.network_info JSON, we have to iterate one by one to find the instance that matches the request. Which makes this filter un-usable in large scale deployment.

Use Cases

As an operator, I want to efficiently filter instances by IP so that I can locate the instances that have abnormal network activities on the provided IP address(es).

Proposed change

As discussed in Queens PTG 1, one possible solution is to get filtered ports according to the provided IP addresses from Neutron and retrieve the instance uuid from the port.device_id and then merge to the other filters.

Nova currently support filtering instances by IP address using regex matching manner. But the Neutron port list API does not support regex matching filtering. A RFE has been submitted in Neutron 2 to support this. The changes in Nova side will depend on the enhancement in Neutron side.

As a newer version of Nova may talk to older version of Neutron, we will also add logic that check whether regex matching is supported in Neutron side via a new networking API extension. If the extension is not available, we will fallback to the existing behavior and avoid erroneously filter out all instances.

Nova currently also support list and filter deleted instances by IP address, after this change, user will not able to filter deleted instances with IP address since Neutron cannot provide such data. This is considered to be acceptable as there are no guarantees that users can list deleted instances today since an operator can archive/purge deleted instances at any point.

Alternatives

An alternative raised up at Queens PTG was storing the IPs in a mapping table in Nova database for query. The issue with this is that we already store the IPs in the instance_info_caces.network_info column and we have to work on keeping that accurate, storing the data yet in another place could lead to more bugs as we have to manage state in 3 different locations, Neutron(the source of truth), instance info cache and the new mapping table.

Data model impact

None

REST API impact

Users will not able to list deleted instances with IP filter after this change.

Security impact

None

Notifications impact

None

Other end user impact

None

Performance Impact

This change will improve the performance when filtering instances by IP addresses.

Benchmarking and comparision test at scale (at least 1000 instances) will be performed with the POC and test result will be provided.

Other deployer impact

None

Developer impact

None

Implementation

Assignee(s)

Primary assignee:

Kevin Zheng <zhengzhenyu@huawei.com>

Work Items

  • Add logic to query filtered ports from Neutron

  • Merge the results with other filters

  • Add related doc and reno

Dependencies

As Nova provides regex matching manner filtering for IP filter, so this is depend on Neutron changes that adds regex matching manner to the GET /ports API 2.

Testing

Add the following tests.

  • Unit tests

Documentation Impact

None

References

1

Queens PTG discussion recap: http://lists.openstack.org/pipermail/openstack-dev/2017-September/122258.html

2(1,2)

Neutron RFE to support regex matching when filter ports by IP address: https://bugs.launchpad.net/neutron/+bug/1718605

History

Revisions

Release Name

Description

Queens

Proposed

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nova-specs