Use Calico instead of Flannel¶

If you want to use NetworkPolicy you can use Calico in k3s instead of Flannel.

1. Download and modify the Calico descriptor¶

You can following the documentation

And then you have to change the ConfigMap calico-config. On the cni_network_config add the entry for allowing IP forwarding

json "container_settings": { "allow_ip_forwarding": true }

Or you can directly use this calico.yaml manifest

2. Create the cluster without flannel and with calico¶

On the k3s cluster creation :

add the flag --flannel-backend=none. For this, on k3d you need to forward this flag to k3s with the option --k3s-arg.
mount (--volume) the calico descriptor in the auto deploy manifest directory of k3s /var/lib/rancher/k3s/server/manifests/

So the command of the cluster creation is (when you are at root of the k3d repository)

bash k3d cluster create "${clustername}" \ --k3s-arg '--flannel-backend=none@server:*' \ --volume "$(pwd)/docs/usage/guides/calico.yaml:/var/lib/rancher/k3s/server/manifests/calico.yaml"

In this example :

change "${clustername}" with the name of the cluster (or set a variable).
$(pwd)/docs/usage/guides/calico.yaml is the absolute path of the calico manifest, you can adapt it.

You can add other options, see.

The cluster will start without flannel and with Calico as CNI Plugin.

For watching for the pod(s) deployment

bash watch "kubectl get pods -n kube-system"

You will have something like this at beginning (with the command line `#!bash kubectl get pods -n kube-system`)

bash NAME READY STATUS RESTARTS AGE helm-install-traefik-pn84f 0/1 Pending 0 3s calico-node-97rx8 0/1 Init:0/3 0 3s metrics-server-7566d596c8-hwnqq 0/1 Pending 0 2s calico-kube-controllers-58b656d69f-2z7cn 0/1 Pending 0 2s local-path-provisioner-6d59f47c7-rmswg 0/1 Pending 0 2s coredns-8655855d6-cxtnr 0/1 Pending 0 2s

And when it finish to start

bash NAME READY STATUS RESTARTS AGE metrics-server-7566d596c8-hwnqq 1/1 Running 0 56s calico-node-97rx8 1/1 Running 0 57s helm-install-traefik-pn84f 0/1 Completed 1 57s svclb-traefik-lmjr5 2/2 Running 0 28s calico-kube-controllers-58b656d69f-2z7cn 1/1 Running 0 56s local-path-provisioner-6d59f47c7-rmswg 1/1 Running 0 56s traefik-758cd5fc85-x8p57 1/1 Running 0 28s coredns-8655855d6-cxtnr 1/1 Running 0 56s

Note :

you can use the auto deploy manifest or a kubectl apply depending on your needs
Calico is not as quick as Flannel (but it provides more features)

References¶

Last update: October 11, 2021