# -- Background
The Quantum Linux Bridge plugin is a plugin that allows you to manage
connectivity between VMs on hosts that are capable of running a Linux Bridge.
The Quantum Linux Bridge plugin consists of three components:
1) The plugin itself: The plugin uses a database backend (mysql for
now) to store configuration and mappings that are used by the
agent. The mysql server runs on a central server (often the same
host as nova itself).
2) The quantum service host which will be running quantum. This can
be run on the server running nova.
3) An agent which runs on the host and communicates with the host operating
system. The agent gathers the configuration and mappings from
the mysql database running on the quantum host.
The sections below describe how to configure and run the quantum
service with the Linux Bridge plugin.
# -- Python library dependencies
Make sure you have the following package(s) installedi on quantum server
host as well as any hosts which run the agent:
python-configobj
bridge-utils
python-mysqldb
sqlite3
# -- Nova configuration (controller node)
1) Ensure that the quantum network manager is configured in the
nova.conf on the node that will be running nova-network.
network_manager=nova.network.quantum.manager.QuantumManager
# -- Nova configuration (compute node(s))
1) Configure the vif driver, and libvirt/vif type
connection_type=libvirt
libvirt_type=qemu
libvirt_vif_type=ethernet
libvirt_vif_driver=nova.virt.libvirt.vif.QuantumLinuxBridgeVIFDriver
linuxnet_interface_driver=nova.network.linux_net.QuantumLinuxBridgeInterfaceDriver
2) If you want a DHCP server to be run for the VMs to acquire IPs,
add the following flag to your nova.conf file:
quantum_use_dhcp=true
(Note: For more details on how to work with Quantum using Nova, i.e. how to create networks and such,
please refer to the top level Quantum README which points to the relevant documentation.)
# -- Quantum configuration
Make the Linux Bridge plugin the current quantum plugin
- edit quantum.conf and change the core_plugin according to the API version
V1: "core_plugin = quantum.plugins.linuxbridge.LinuxBridgePlugin.LinuxBridgePlugin"
V2: "core_plugin = quantum.plugins.linuxbridge.lb_quantum_plugin.LinuxBridgePluginV2"
# -- Database config.
(Note: The plugin ships with a default SQLite in-memory database configuration,
and can be used to run tests without performing the suggested DB config below.)
The Linux Bridge quantum plugin requires access to a mysql database in order
to store configuration and mappings that will be used by the agent. Here is
how to set up the database on the host that you will be running the quantum
service on.
MySQL should be installed on the host, and all plugins and clients
must be configured with access to the database.
To prep mysql, run:
$ mysql -u root -p -e "create database quantum_linux_bridge"
# log in to mysql service
$ mysql -u root -p
# The Linux Bridge Quantum agent running on each compute node must be able to
# make a mysql connection back to the main database server.
mysql> GRANT USAGE ON *.* to root@'yourremotehost' IDENTIFIED BY 'newpassword';
# force update of authorization changes
mysql> FLUSH PRIVILEGES;
(Note: If the remote connection fails to MySQL, you might need to add the IP address,
and/or fully-qualified hostname, and/or unqualified hostname in the above GRANT sql
command. Also, you might need to specify "ALL" instead of "USAGE".)
# -- Plugin configuration
- Edit the configuration file:
etc/quantum/plugins/linuxbridge/linuxbridge_conf.ini
Make sure it matches your mysql configuration. This file must be updated
with the addresses and credentials to access the database.
Note: When running the tests, set the connection type to sqlite, and when
actually running the server set it to mysql. At any given time, only one
of these should be active in the conf file (you can comment out the other).
- Remember to change the interface configuration to indicate the correct
ethernet interface on that particular host which is being used to participate
in the Quantum networks. This configuration has to be applied on each host
on which the agent runs.
# -- Agent configuration
- Edit the configuration file:
etc/quantum/plugins/linuxbridge/linuxbridge_conf.ini
- Copy quantum/plugins/linuxbridge/agent/linuxbridge_quantum_agent.py
and etc/quantum/plugins/linuxbridge/linuxbridge_conf.ini
to the compute node.
$ Run the following:
python linuxbridge_quantum_agent.py linuxbridge_conf.ini
(Use --verbose option to see the logs)
Note that the the user running the agent must have sudo priviliges
to run various networking commands. Also, the agent can be
configured to use quantum-rootwrap, limiting what commands it can
run via sudo. See http://wiki.openstack.org/Packager/Rootwrap for
details on rootwrap.
As an alternative to coping the agent python file, if quantum is
installed on the compute node, the agent can be run as
bin/quantum-linuxbridge-agent.
# -- Running Tests
(Note: The plugin ships with a default SQLite in-memory database configuration,
and can be used to run tests out of the box. Alternatively you can perform the
DB configuration for a persistent database as mentioned in the Database
Configuration section.)
- To run tests related to the Plugin and the VLAN management (run the
following from the top level Quantum directory):
PLUGIN_DIR=quantum/plugins/linuxbridge ./run_tests.sh -N
- The above will not however run the tests for the agent (which deals
with creating the bridge and interfaces). To run the agent tests, run the
following from the top level Quantum directory:
sudo PLUGIN_DIR=quantum/plugins/linuxbridge ./run_tests.sh -N tests.unit._test_linuxbridgeAgent
(Note: To run the agent tests you should have the environment setup as
indicated in the Agent Configuration, and also have the necessary dependencies
insalled.)
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