openstack/training-guides
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Labs: Wait for external bridge

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If we change configuration files right after installing service
packages, automatically started services may pick up changed
configuration files rather than the default files they were packaged
with.

If the neutron-l3-agent starts with our custom configuration file which
refers to the external bridge br-ex while that bridge is not there
(yet), the port is permanently marked as unavailable (vlan tag=4095).

In such a case, a line like this can be found in /etc/openvswitch/conf.db:
{"_date":1435514607570,
"Port":{"20b0e96c-6103-46e6-a234-a4d5439eece7":{"tag":4095}}, "_comment":"
ovs-vsctl: /usr/bin/ovs-vsctl --timeout=10 set Port qr-4be1ab91-60 tag=4095"
,"Open_vSwitch":{"e00f3d6f-e55a-419a-a605-141021026dee":{"next_cfg":15}}}

For additional information, check this neutron bug:
Neutron openvswitch-agent doesn't recover ports from binding_failed status
https://bugs.launchpad.net/neutron/+bug/1399249

This is another race -- waiting for a few seconds before changing the
configuration files fixes the problem. The alternative used in this
patch is to stop the neutron-l3-agent before editing the configuration
files and to start it only once the bridge is ready.

Change-Id: I55762d17817e5e1cdb4c0420374c9fbc314bdff1
Co-Authored-By: Vigneshvar.A.S <vigneshvar.a.s@gmail.com>
Co-Authored-By: sayalilunkad <sayali.92720@gmail.com>
This commit is contained in:
Roger Luethi 2015-06-28 20:07:55 +02:00 committed by Pranav Salunke
parent 7e76480468
commit 29efa4a3e7
1 changed files with 23 additions and 0 deletions
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23
labs/scripts/ubuntu/setup_neutron_network.sh
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@ -30,6 +30,16 @@ echo "Installing networking components for network node."
sudo apt-get install -y neutron-plugin-ml2 neutron-plugin-openvswitch-agent \
neutron-l3-agent neutron-dhcp-agent
# neutron-l3-agent has just been installed and is about to start. We are also
# about to change its configuration file which tends to result in the agent
# starting up with our changed configuration before the external bridge is
# ready which ends with a misconfigured system (port with tag=4095). We can
# either wait here for neutron-l3-agent to start with the old configuration
# files, or shut it down now and start it with the new configuration files once
# configuration files _and_ the external bridge are ready.
echo "Stopping neutron-l3-agent for now."
#sudo service neutron-l3-agent stop
echo "Configuring neutron for network node."
neutron_admin_user=$(service_to_user_name neutron)
@ -176,6 +186,19 @@ echo "Restarting the network service."
sudo service neutron-plugin-openvswitch-agent restart
sudo service neutron-l3-agent restart
echo -n "Checking VLAN tags."
# Wait for "tag:" to show up
until sudo ovs-vsctl show|grep tag:; do
echo -n "."
sleep 1
done
if sudo ovs-vsctl show|grep "tag: 4095"; then
# tag: 4095 indicates an error
echo >&2 "ERROR: port is in limbo and won't recover:"
grep tag=4095 /etc/openvswitch/conf.db >&2
exit 1
fi
echo -n "Getting router namespace."
until ip netns|grep qrouter; do
echo -n "."