Learn about Kata Containers with Juju and Charmed Kubernetes

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Experimenting with Kata Containers on your Kubernetes cluster managed with Juju takes commands. From a recent post on the Ubuntu blog:

One of the fastest ways to get started with Kata Containers is to deploy it in the Charmed Kubernetes environment. Once you have Charmed Kubernetes up and running, there are just four commands to deploy this extension:

$ juju deploy cs:~containers/kata
$ juju relate kata kubernetes-master
$ juju relate kata kubernetes-worker
$ juju relate kata:untrusted containerd:untrusted

The first one deploys the Kata Containers runtime, while the other ones configure Kubernetes services to use it. Such an approach is scalable even in clusters consisting of hundreds of nodes.

Once deployed, you can use the new runtime in a very intuitive way. First, create a RuntimeClass object:

$ echo <EOF >> kata.yaml
apiVersion: node.k8s.io/v1beta1
kind: RuntimeClass
metadata:
  name: kata
handler: kata
EOF

$ kubectl create -f kata.yaml
runtimeclass.node.k8s.io/kata created

Then you can refer it when creating a pod or deployment. Simply add a runtimeClassName parameter to the spec section of your YAML file and refer to the class you created. for example:

$ cat nginx-kata.yaml 
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: nginx-kata
  name: nginx-kata
spec:
  runtimeClassName: kata
  containers:
  - image: nginx
    name: nginx-kata
    resources: {}
  dnsPolicy: ClusterFirst
  restartPolicy: Never>
status: {}

Now when creating the nginx-kata pod, it will be created using the Kata Containers runtime.

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