Scenario - Using Open vSwitch¶
Overview¶
Operators can choose to utilize Open vSwitch instead of Linux Bridges for the neutron ML2 agent. This offers different capabilities and integration points with neutron. This document outlines how to set it up in your environment.
Recommended reading¶
We recommend that you read the following documents before proceeding:
- Neutron documentation on Open vSwitch OpenStack deployments: https://docs.openstack.org/liberty/networking-guide/scenario-classic-ovs.html
- Blog post on how OpenStack-Ansible works with Open vSwitch: https://medium.com/@travistruman/configuring-openstack-ansible-for-open-vswitch-b7e70e26009d
Prerequisites¶
All compute nodes must have bridges configured:
br-mgmtbr-vlan(optional - used for vlan networks)br-vxlan(optional - used for vxlan tenant networks)br-storage(optional - used for certain storage devices)
For more information see: https://docs.openstack.org/project-deploy-guide/openstack-ansible/newton/targethosts-networkconfig.html
These bridges may be configured as either a Linux Bridge (which would connect to the Open vSwitch controlled by neutron) or as an Open vSwitch.
Configuring bridges (Linux Bridge)¶
The following is an example of how to configure a bridge (example: br-mgmt)
with a Linux Bridge on Ubuntu 16.04 LTS:
/etc/network/interfaces
auto lo
iface lo inet loopback
# Management network
auto eth0
iface eth0 inet manual
# VLAN network
auto eth1
iface eth1 inet manual
source /etc/network/interfaces.d/*.cfg
/etc/network/interfaces.d/br-mgmt.cfg
# OpenStack Management network bridge
auto br-mgmt
iface br-mgmt inet static
bridge_stp off
bridge_waitport 0
bridge_fd 0
bridge_ports eth0
address MANAGEMENT_NETWORK_IP
netmask 255.255.255.0
One br-<type>.cfg is required for each bridge. VLAN interfaces can be used
to back the br-<type> bridges if there are limited physical adapters on the
system.
Configuring bridges (Open vSwitch)¶
Another configuration method routes everything with Open vSwitch. The bridge
(example: br-mgmt) can be an Open vSwitch itself.
The following is an example of how to configure a bridge (example: br-mgmt)
with Open vSwitch on Ubuntu 16.04 LTS: *
/etc/network/interfaces
auto lo
iface lo inet loopback
source /etc/network/interfaces.d/*.cfg
# Management network
allow-br-mgmt eth0
iface eth0 inet manual
ovs_bridge br-mgmt
ovs_type OVSPort
# VLAN network
allow-br-vlan eth1
iface eth1 inet manual
ovs_bridge br-vlan
ovs_type OVSPort
/etc/network/interfaces.d/br-mgmt.cfg
# OpenStack Management network bridge
auto br-mgmt
allow-ovs br-mgmt
iface br-mgmt inet static
address MANAGEMENT_NETWORK_IP
netmask 255.255.255.0
ovs_type OVSBridge
ovs_ports eth0
One br-<type>.cfg is required for each bridge. VLAN interfaces can be used
to back the br-<type> bridges if there are limited physical adapters on the
system.
Warning: There is a bug in Ubuntu 16.04 LTS where the Open vSwitch service won’t start properly when using systemd. The bug and workaround are discussed here: http://www.opencloudblog.com/?p=240
OpenStack-Ansible user variables¶
Create a group var file for your network hosts
/etc/openstack_deploy/group_vars/network_hosts. It has to include:
# Ensure the openvswitch kernel module is loaded
openstack_host_specific_kernel_modules:
- name: "openvswitch"
pattern: "CONFIG_OPENVSWITCH"
Specify provider network definitions in your
/etc/openstack_deploy/openstack_user_config.yml that define
one or more Neutron provider bridges and related configuration:
Note
Bridges specified here will be created automatically. If
network_interface is defined, the interface will be placed into
the bridge automatically.
- network:
container_bridge: "br-provider"
container_type: "veth"
type: "vlan"
range: "101:200,301:400"
net_name: "physnet1"
network_interface: "bond1"
group_binds:
- neutron_openvswitch_agent
- network:
container_bridge: "br-provider2"
container_type: "veth"
type: "vlan"
range: "203:203,467:500"
net_name: "physnet2"
network_interface: "bond2"
group_binds:
- neutron_openvswitch_agent
When using flat provider networks, modify the network type accordingly:
- network:
container_bridge: "br-publicnet"
container_type: "veth"
type: "flat"
net_name: "flat"
group_binds:
- neutron_openvswitch_agent
Specify an overlay network definition in your
/etc/openstack_deploy/openstack_user_config.yml that defines
overlay network-related configuration:
Note
The bridge name should correspond to a pre-created Linux bridge or OVS bridge.
- network:
container_bridge: "br-vxlan"
container_type: "veth"
container_interface: "eth10"
ip_from_q: "tunnel"
type: "vxlan"
range: "1:1000"
net_name: "vxlan"
group_binds:
- neutron_openvswitch_agent
Set the following user variables in your
/etc/openstack_deploy/user_variables.yml:
neutron_plugin_type: ml2.ovs
neutron_ml2_drivers_type: "flat,vlan,vxlan"
The overrides are instructing Ansible to deploy the OVS mechanism driver and
associated OVS components. This is done by setting neutron_plugin_type
to ml2.ovs.
The neutron_ml2_drivers_type override provides support for all common type
drivers supported by OVS.
If provider network overrides are needed on a global or per-host basis,
the following format can be used in user_variables.yml or per-host
in openstack_user_config.yml.
Note
These overrides are not normally required when defining global provider
networks in the openstack_user_config.yml file.
# When configuring Neutron to support vxlan tenant networks and
# vlan provider networks the configuration may resemble the following:
neutron_provider_networks:
network_types: "vxlan"
network_vxlan_ranges: "1:1000"
network_vlan_ranges: "physnet1:102:199"
network_mappings: "physnet1:br-provider"
network_interface_mappings: "br-provider:bond1"
# When configuring Neutron to support only vlan tenant networks and
# vlan provider networks the configuration may resemble the following:
neutron_provider_networks:
network_types: "vlan"
network_vlan_ranges: "physnet1:102:199"
network_mappings: "physnet1:br-provider"
network_interface_mappings: "br-provider:bond1"
# When configuring Neutron to support multiple vlan provider networks
# the configuration may resemble the following:
neutron_provider_networks:
network_types: "vlan"
network_vlan_ranges: "physnet1:102:199,physnet2:2000:2999"
network_mappings: "physnet1:br-provider,physnet2:br-provider2"
network_interface_mappings: "br-provider:bond1,br-provider2:bond2"
# When configuring Neutron to support multiple vlan and flat provider
# networks the configuration may resemble the following:
neutron_provider_networks:
network_flat_networks: "*"
network_types: "vlan"
network_vlan_ranges: "physnet1:102:199,physnet2:2000:2999"
network_mappings: "physnet1:br-provider,physnet2:br-provider2"
network_interface_mappings: "br-provider:bond1,br-provider2:bond2"
Open Virtual Switch (OVS) commands¶
The following commands can be used to provide useful information about the state of Open vSwitch networking and configurations.
The ovs-vsctl show command provides information about the virtual switches
and connected ports currently configured on the host:
root@infra01:~# ovs-vsctl show
4ef304ff-b803-4d09-95f5-59a076323949
Manager "ptcp:6640:127.0.0.1"
is_connected: true
Bridge br-int
Controller "tcp:127.0.0.1:6633"
is_connected: true
fail_mode: secure
Port "tap2e7e0507-e4"
tag: 2
Interface "tap2e7e0507-e4"
type: internal
Port int-br-vlan
Interface int-br-vlan
type: patch
options: {peer=phy-br-provider}
Port br-int
Interface br-int
type: internal
Port "tap7796ab3d-e9"
tag: 5
Interface "tap7796ab3d-e9"
type: internal
Port patch-tun
Interface patch-tun
type: patch
options: {peer=patch-int}
Bridge br-tun
Controller "tcp:127.0.0.1:6633"
is_connected: true
fail_mode: secure
Port "vxlan-ac1df015"
Interface "vxlan-ac1df015"
type: vxlan
options: {df_default="true", in_key=flow, local_ip="172.29.240.20", out_key=flow, remote_ip="172.29.240.21"}
Port patch-int
Interface patch-int
type: patch
options: {peer=patch-tun}
Port "vxlan-ac1df017"
Interface "vxlan-ac1df017"
type: vxlan
options: {df_default="true", in_key=flow, local_ip="172.29.240.20", out_key=flow, remote_ip="172.29.240.23"}
Port br-tun
Interface br-tun
type: internal
Bridge br-provider
Controller "tcp:127.0.0.1:6633"
is_connected: true
fail_mode: secure
Port "ens192"
Interface "ens192"
Port br-provider
Interface br-provider
type: internal
Port phy-br-provider
Interface phy-br-provider
type: patch
options: {peer=int-br-provider}
ovs_version: "2.10.0"
Additional commands can be found in upstream Open vSwitch documentation.
Notes¶
The neutron-openvswitch-agent service will check in as an agent
and can be observed using the openstack network agent list command:
root@infra01-utility-container-ce1509fd:~# openstack network agent list --agent-type open-vswitch
+--------------------------------------+--------------------+-------------+-------------------+-------+-------+---------------------------+
| ID | Agent Type | Host | Availability Zone | Alive | State | Binary |
+--------------------------------------+--------------------+-------------+-------------------+-------+-------+---------------------------+
| 4dcef710-ec0c-4925-a940-dc319cd6849f | Open vSwitch agent | compute03 | None | :-) | UP | neutron-openvswitch-agent |
| 5e1f8670-b90e-49c3-84ff-e981aeccb171 | Open vSwitch agent | compute02 | None | :-) | UP | neutron-openvswitch-agent |
| 78746672-d77a-4d8a-bb48-f659251fa246 | Open vSwitch agent | compute01 | None | :-) | UP | neutron-openvswitch-agent |
| eebab5da-3ef5-4582-84c5-f29e2472a44a | Open vSwitch agent | infra01 | None | :-) | UP | neutron-openvswitch-agent |
+--------------------------------------+--------------------+-------------+-------------------+-------+-------+---------------------------+
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