BGP Setup with ovn-bgp-agent

OpenStack neutron with ovn supports the ovn-bgp-agent to announce customer networks to an external network. Yaook is able to create and configure this bgp agents.

Technical Setup

Yaook assumes, the bgp agent needs to speak to the external network, to announce routes. Therefore the agent needs to be connected to the external network.

To create this connection, Yaook creates a Pod running the ovn-bgp-agent, with it’s own pod network namespace. A ovs port is created, attached to the ovs bridge representing the external network. The port is connected to the bgp pod network namespace and gets an IP address, so bgp agent can use it to communicate to the external network.

This way, we achieve connection the bgp agent with the external network and still protect the nodes running the pods from being directly connected to the external network.

Setup and configure a bgp agent

To run a ovnbgpagent using Yaook, some options needs to be configured:

  1. add bgp configuration at neutron deployment

  2. set IP annotation to nodes running the bgp agents

  3. set ID annotation to the nodes running the bgp agents

  4. set bgp label to nodes running the agents

add bgp configuration

see also Neutron using ovn

Edit your neutron deployment to have at spec:setup:ovn the section bgp. Next define a config_key with any name you want and define the configTemplates as value. The name will be used for naming the agents. As only one bgp agent can run one speaker (but a speaker can have many agents, e.g. at each node agent), you need to configure many config_keys to run for each speaker bgp agents.

One required config option is the bridgeName, where the bridge name of the ovs bridge needs to be defined, the bgp agent should be connected to. It is the same name like one of the bridges, defined in ovn:bridge_mappings at l2 section.

As this bridge is mostly setup at nodes with label network.yaook.cloud/neutron-ovn-agent: “true”, you can also run the bgp agent on these nodes. But it can also run on different nodes, make sure the bridge_mappings exists there.

Additionaly define addressScopes, driver, localAS and peers.

IP annotation

Yaook needs to know, which IP to define at the interface connected to the external network (via ovs bridge) used for bgp agent.

Therefore an annotation needs to be set, containing the config_key. Value is the IP address with subnet.

Annotation prefix: bgp-interface-ip.network.yaook.cloud/ (At the code the variable ANNOTATION_BGP_INTERFACE_IP is used.)

Example: bgp-interface-ip.network.yaook.cloud/mybgpspeaker: 10.2.4.42/24

ID annotation

Yaook also needs to know the ID of the bgp speaker.

Therefore an annotation needs to be set, containing the config_key. Value is the IP address without subnet or an unsigned integer.

Annotation prefix: bgp-router-id.network.yaook.cloud/ (At the code the variable ANNOTATION_BGP_ROUTER_ID is used.)

Example: bgp-router-id.network.yaook.cloud/mybgpspeaker: 10.2.4.42

bgp label at nodes

see also Scheduling

Each component started by Yaook will only be scheduled on nodes with specific labels. This is used do define, which component should run on which nodes.

For bgp set the label network.yaook.cloud/neutron-bgp-agent=true (code use the variable NETWORK_NEUTRON_BGP_AGENT)