FRR BFD Session

In this document, I will describe how to set up an environment and simulate a BFD session (using FRR) between Kind cluster with two nodes - and an external container.

Prerequisites

• Go 1.15+
• Python 3
• KIND - Kubernetes in Docker
• kubectl

Setting up a development environment

Clone the metallb repository. From the root of your git clone, run:

inv dev-env -p bgp

This command will create a Kubernetes cluster with 2 nodes and a FRR container.

Create the FRR pods

First you'll need to create a configmap with all the BFD configurations. After you cloned this repository, enter:

k create configmap frr-config --from-file=./configmap/

The configmap folder includes:

configmap
|   daemons
|   frr.conf
|   vtysh.conf

Apply the daemonset yaml:

k apply -f daemonset.yaml

The daemonset will inject those files into the etc/frr directory in the FRR pods.

Configure the FRR container

First, inspect the pod's IP addresses:

k get pods -o wide

Then edit the frr.conf file inside the frr-container folder and paste the IP addresses:

bfd
 peer 172.18.0.X
   no shutdown
 !
 peer 172.18.0.Y
   no shutdown
 !
!

Next, enter the FRR container:

docker exec -it frr sh

In daemons file edit bfdd from "no" to "yes". In frr.conf paste the contant of frr-container/frr.conf.

cd etc/frr
vi daemons
vi frr.conf

We then restart the container to apply the new configurations.

exit
docker restart frr

Test the BFD session

In this point, the BFD session should be up and running. Let's assert this:

docker exec -it frr sh
vtysh
sh bfd peers brief

The output should look like this:

Session count: 2
SessionId  LocalAddress                             PeerAddress                             Status         
=========  ============                             ===========                             ======         
2917389698 172.18.0.5                               172.18.0.4                              up             
1501100564 172.18.0.5                               172.18.0.3                              up  

Now, delete one of the pods from the kind cluster, and check the connectivity again from the container. This time it should look like this:

Session count: 2
SessionId  LocalAddress                             PeerAddress                             Status         
=========  ============                             ===========                             ======         
2917389698 172.18.0.5                               172.18.0.4                              up             
1501100564 172.18.0.5                               172.18.0.3                              down 

---

For clean up enter: inv dev-env-cleanup