Remove and recreate interfacein ovs if already exists

[Aaron Rosen]

If the dhcp-agent machine restarts and openvswitch logs the following
warning message for all tap interfaces that have not been recreated yet:

bridge|WARN|could not open network device tap2cf7dbad-9d (No such device)

Once the dhcp-agent starts he recreates the interfaces and readds them to the
ovs-bridge. Unfortinately, ovs does not reinitalize the interface as its
already in ovsdb and does not assign it an ofport number.

In order to correct this we should first remove interfaces that exist and
then readd them.

root@arosen-desktop:~# ovs-vsctl -- --may-exist add-port br-int fake1

# ofport still -1
root@arosen-desktop:~# ovs-vsctl list inter | grep -A 2 fake1
name : "fake1"
ofport : -1
ofport_request : []
root@arosen-desktop:~# ip link add fake1 type veth peer name fake11
root@arosen-desktop:~# ifconfig fake1
fake1 Link encap:Ethernet HWaddr 56:c3:a1:2b:1f:f4
          BROADCAST MULTICAST MTU:1500 Metric:1
          RX packets:0 errors:0 dropped:0 overruns:0 frame:0
          TX packets:0 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:0 (0.0 B) TX bytes:0 (0.0 B)

root@arosen-desktop:~# ovs-vsctl list inter | grep -A 2 fake1
name : "fake1"
ofport : -1
ofport_request : []
root@arosen-desktop:~# ovs-vsctl -- --may-exist add-port br-int fake1
root@arosen-desktop:~# ovs-vsctl list inter | grep -A 2 fake1
name : "fake1"
ofport : -1
ofport_request : []

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/66451

[yong sheng gong (gongysh)]

it seems has nothing to do with dhcp agent. in fact, if the port's interface is internal, the '-1' of ofport should not happen at all.
but it actually happens to non-internal interface port.

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/66451
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=b78eea6146145793a7c61705a1602cf5e9ac3d3a
Submitter: Jenkins
Branch: master

commit b78eea6146145793a7c61705a1602cf5e9ac3d3a
Author: Aaron Rosen <email address hidden>
Date: Mon Jan 13 13:57:04 2014 -0800

    Remove and recreate interface if already exists

    If the dhcp-agent machine restarts when openvswitch comes up it logs the
    following warning messages for all tap interfaces that do not exist:

    bridge|WARN|could not open network device tap2cf7dbad-9d (No such device)

    Once the dhcp-agent starts it recreates the interfaces and re-adds them to the
    ovs-bridge. Unfortunately, ovs does not reinitialize the interfaces as they
    are already in ovsdb and does not assign them a ofport number.

    This situation corrects itself though the next time a port is added to the
    ovs-bridge which is why no one has probably noticed this issue till now.

    In order to correct this we should first remove interface that exist and
    then readd them.

    Closes-bug: #1268762

    Change-Id: I4bb0019135ab7fa7cdfa6d5db3bff6eafe22fc85

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: stable/havana
Review: https://review.openstack.org/72253

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/72253
Committed: https://git.openstack.org/cgit/openstack/neutron/commit/?id=c7596bf8c952ecc6d73ff50a6ae9ec6384b94cd1
Submitter: Jenkins
Branch: stable/havana

commit c7596bf8c952ecc6d73ff50a6ae9ec6384b94cd1
Author: Aaron Rosen <email address hidden>
Date: Mon Jan 13 13:57:04 2014 -0800

    Remove and recreate interface if already exists

    If the dhcp-agent machine restarts when openvswitch comes up it logs the
    following warning messages for all tap interfaces that do not exist:

    bridge|WARN|could not open network device tap2cf7dbad-9d (No such device)

    Once the dhcp-agent starts it recreates the interfaces and re-adds them to the
    ovs-bridge. Unfortunately, ovs does not reinitialize the interfaces as they
    are already in ovsdb and does not assign them a ofport number.

    This situation corrects itself though the next time a port is added to the
    ovs-bridge which is why no one has probably noticed this issue till now.

    In order to correct this we should first remove interface that exist and
    then readd them.

    Closes-bug: #1268762

    Change-Id: I4bb0019135ab7fa7cdfa6d5db3bff6eafe22fc85
    (cherry picked from commit b78eea6146145793a7c61705a1602cf5e9ac3d3a)

[Pavel Kirpichyov (pavel-kirpichyov)]

After pulling this change to havana it breaking port tagging (deletes port with tag, creates port without tag)