Atomic ExtraRoute Resource

Start using Neutron's extraroute-atomic API to make OS::Neutron::ExtraRoute free of lost updates because of concurrency problems. Related Neutron spec: https://review.opendev.org/655680 Change-Id: Ie9f6f47f17befd6a4e79e02e9f10b192927b6bd2 Story: #2005522 Task: #30641
2019-04-26 14:28:40 +02:00 · 2019-04-26 14:28:40 +02:00 · 629c250f61
parent 54015065d3
commit 629c250f61
1 changed files with 109 additions and 0 deletions
--- a/specs/train/atomic-extraroute.rst
+++ b/specs/train/atomic-extraroute.rst
@ -0,0 +1,109 @@
+..
+ This work is licensed under a Creative Commons Attribution 3.0 Unported
+ License.
+
+ http://creativecommons.org/licenses/by/3.0/legalcode
+
+==========================
+Atomic ExtraRoute Resource
+==========================
+
+https://storyboard.openstack.org/#!/story/2005522
+
+As we improve Neutron's extraroute API we could adapt Heat's
+OS::Neutron::ExtraRoute resource to use the improved API and via that
+turn the resource to a supported resource.
+
+Problem description
+===================
+
+As discussed in an `openstack-discuss thread
+<http://lists.openstack.org/pipermail/openstack-discuss/2019-April/005121.html>`_
+we could improve the Neutron's extraroute API to better support Neutron
+API clients, especially Heat.
+
+The problem is that the current extraroute API does not allow atomic
+additions/deletions of particular routing table entries. In the current
+API the routes attribute of a router (containing all routing table
+entries) must be updated at once. Therefore additions and deletions
+must be performed on the client side. Therefore multiple clients race
+to update the routes attribute and updates may get lost.
+
+Proposed change
+===============
+
+Change OS::Neutron::ExtraRoute to use the new Neutron API (extension
+extraroute-atomic) as it is specified in the `Atomic Extraroute API
+Neutron RFE <https://bugs.launchpad.net/neutron/+bug/1826396>`_.
+
+Keep the resource template format as it is today, that is:
+
+::
+
+  extraroute0:
+    type: OS::Neutron::ExtraRoute
+    properties:
+      destination: 10.1.0.0/24
+      nexthop: 10.0.0.10
+      router_id: { get_resource: router0 }
+
+Unit test and document the change.
+
+Change the resource's support_status to SUPPORTED.
+
+Alternatives
+------------
+
+We could introduce a OS::Neutron::ExtraRoutes resource (please note the
+plural). Internally the the resource implementation would still use the
+improved Neutron extraroute-atomic API. But the template syntax could allow
+multiple routes in one resource;
+
+::
+
+  extraroute1:
+    type: OS::Neutron::ExtraRoutes
+    properties:
+      router_id: { get_resource: router0 }
+      routes:
+        - destination: 10.1.0.0/24
+          nexthop: 10.0.0.10
+
+This format could allow more efficient use of the Neutron API. But it would
+be backwards incompatible with the previous unsupported
+OS::Neutron::ExtraRoute resource.
+
+Even if going with the proposed template syntax we may want to introduce a
+new resource name to express the difference in behavior, for example:
+OS::Neutron::AtomicExtraRoute.
+
+Implementation
+==============
+
+Assignee(s)
+-----------
+
+Primary assignee: Bence Romsics <bence.romsics@ericsson.com>
+
+Milestones
+----------
+
+Target Milestone for completion: Not known yet, please see Dependencies
+(but I hope to complete the whole Neutron+Heat feature in the Train cycle,
+so either milestone 2 or 3 for Heat).
+
+Work Items
+----------
+
+* Change the resource implementation.
+* Unit test the resource implementation.
+* Document the change.
+
+Dependencies
+============
+
+The completion of the Neutron API change is a pre-requisite to the proposed
+Heat change. The proposed Neutron change is also under review at the time of
+first publishing this spec. This spec may or may not need an update after the
+Neutron spec is merged. All cross-project spec review is warmly welcome so
+we can create a Neutron API that's easy to consume from Heat.