DVR: router namespace is not getting removed once all VMs from a compute node migrates to other node

[Hardik Italia]

Setup:
1) Multimode setup with 1 controller & 2 compute nodes running linux+KVM.
2) NFS for shared storage. (instances_path = /opt/stack/data/nova/instances is shared)

Steps:
1) Create 2 private networks.
2) Create a DVR router and add an interface to each of the above network.
3) Create 1st VM on private network 1 and on compute node1
4) Create 2nd VM on private network 2 and on compute node 2
5) Migrate VM2 from compute node 2 to compute node 1 (nova live-migrate VM2)
6) Notice that after VM2 migrates to compute node1, router namespace is still there on the compute node 2.

Example:

Before migration: VM11 & VM12 are hosted on the different compute nodes (CN-1 & CN-2).

stack@CTL:~$ nova show vm11 | grep OS-EXT-SRV-ATTR:host
| OS-EXT-SRV-ATTR:host | CN-1 |
| OS-EXT-SRV-ATTR:hostname | vm11
                           |
stack@CTL:~$ nova show vm12 | grep OS-EXT-SRV-ATTR:host
| OS-EXT-SRV-ATTR:host | CN-2 |
| OS-EXT-SRV-ATTR:hostname | vm12 |

Router namespace is present on both the compute nodes:

stack@CN-1:~$ ip netns
qrouter-9d439e4e-c4c6-4901-ba32-0e793b4df3d8

stack@CN-2:~$ sudo ip netns
qrouter-9d439e4e-c4c6-4901-ba32-0e793b4df3d8

After migrating VM12 to CN-1:(Both VMs are now hosted on CN-1)

stack@CTL:~$ nova show vm11 | grep OS-EXT-SRV-ATTR:host
| OS-EXT-SRV-ATTR:host | CN-1 |
| OS-EXT-SRV-ATTR:hostname | vm11 |
stack@CTL:~$ nova show vm12 | grep OS-EXT-SRV-ATTR:host
| OS-EXT-SRV-ATTR:host | CN-1 |
| OS-EXT-SRV-ATTR:hostname | vm12 |

Router namespace is still present on the compute node2 which is not hosting any VMs.

stack@CTL:~$ nova list
+--------------------------------------+------+--------+------------+-------------+------------+
| ID | Name | Status | Task State | Power State | Networks |
+--------------------------------------+------+--------+------------+-------------+------------+
| 0a2f82e0-3edd-47c5-aa24-a29d5b826a55 | vm11 | ACTIVE | - | Running | n1=1.1.1.4 |
| 1274d128-c39c-4598-a8f6-d4629a259bbc | vm12 | ACTIVE | - | Running | n2=2.2.2.3 |

stack@CN-2:~/devstack$ sudo ip netns
qrouter-9d439e4e-c4c6-4901-ba32-0e793b4df3d8

[Oleg Bondarev (obondarev)]

Looks like a duplicate of https://bugs.launchpad.net/neutron/+bug/1508869

[OpenStack Infra (hudson-openstack)]

Change abandoned by Swaminathan Vasudevan (<email address hidden>) on branch: master
Review: https://review.openstack.org/248284
Reason: Duplicate patch. So I will abandon this patch.