Calico CNI on Kubernetes 1.21+

So I decided to go back and build a simple small “native” Kubernetes cluster on my #HomeLab network. I’m using my NFS server as my Cluster Master node. I created another 2 nodes using Ubuntu 20.04. I looked into using VMware’s NSX Container Plugin as my CNI provider. However, the configuration process was a little more intense than I was able to focus on right now. Here is a summary of my configuration:

• OS (all nodes): Ubuntu 20.04.2 LTS
• Kubernetes (kubeadm, kubelet, kubectl, kubernetes-cni): 1.21.0
• Docker CE: 20.10.6
• Calico: 3.17.4

I decided to go with another CNI provider that I have used previously: Calico. Since the Pod CIDR specified in my cluster init call was 10.244.0.0/20, I didn’t have to make any changes to the Calico YAML script. However, when I applied the calico configuration, I received this warning:

Warning: policy/v1beta1 PodDisruptionBudget is deprecated in v1.21+, unavailable in v1.25+; use policy/v1 PodDisruptionBudget
poddisruptionbudget.policy/calico-kube-controllers created

As shown in the warning, the Kubernetes project has moved the PodDisruptionBudget element from their Beta API to the policy/v1 API. As a result, they have deprecated the former API call starting in v1.21 and will be unavailable from v1.25 onwards.

I submitted an Issue to the Calico Project, but in the meantime, here is a fix if you are running the current 1.21 release. After you download the Calico YAML using the following:

$ curl https://docs.projectcalico.org/manifests/calico.yaml -O

Open the calico.yaml file and edit line 3850 (or thereabout). The original section looks like this:

apiVersion: policy/v1beta1
kind: PodDisruptionBudget
metadata:
  name: calico-kube-controllers

Modify the apiVersion line to the following:

apiVersion: policy/v1

Save the file and apply the configuration to your cluster. You shouldn’t get any warnings on your deployment.

Let me know if you have any suggestions or comments. Have fun!