6.3.Kubernetes Deployment

This deploys the demo application to Kubernetes using a standard kubernetes yaml file running the container using root user.

Deploy the application

The corresponding container image is pulled from andifalk/hello-root docker hub repository.

The application is deployed using the following deployment yaml file k8s/deploy.yaml:

apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    app: library-server-root
  name: library-server-root
spec:
  replicas: 1
  selector:
    matchLabels:
      app: library-server-root
  template:
    metadata:
      labels:
        app: library-server-root
    spec:
      containers:
      - image: workshop/library-server-container-root:1.0
        imagePullPolicy: Never
        name: library-server-root
        readinessProbe:
          httpGet:
            path: /library/actuator/health
            port: 9090
          initialDelaySeconds: 5
          periodSeconds: 5
      restartPolicy: Always

Just deploy it by typing kubectl apply -f ./deploy.yaml in directory k8s.

Static analysis of Deployment

Please note that the container is running as root by default and kubernetes also does not prohibit this by default!

Now you can prove that this container does run with root by using a tool like kubeaudit.

kubeaudit nonroot -n default

This should result in an output similar to this:

INFO[0000] Not running inside cluster, using local config
ERRO[0000] RunAsNonRoot is not set in ContainerSecurityContext, which results in root user being allowed!  Container=hello-root...
ERRO[0000] RunAsNonRoot is not set in ContainerSecurityContext, which results in root user being allowed!  Container=hello-root...

An alternative tool for this is popeye, just run it against your current cluster:

popeye

It is also possible to check directly your deployment yaml file:

kube-score score ./deploy.yaml

This will show an output similar to this one:

[CRITICAL] Container Security Context
        · hello-root -> Container has no configured security context
            Set securityContext to run the container in a more secure context.
[CRITICAL] Container Resources
        · hello-root -> CPU limit is not set
            Resource limits are recommended to avoid resource DDOS. Set resources.limits.cpu
        · hello-root -> Memory limit is not set
            Resource limits are recommended to avoid resource DDOS. Set resources.limits.memory

You may also check that the user of the running container is not root using (check your pod name before):

kubectl get pods
...
kubectl exec hello-root-59f59fb9b8-878rk -it -- whoami

Note: If you have deployed the JIB container image then the base image is a distroless image meaning that no shell and no whoami command is inside the container. Therefore you cannot use the command above.

Next

Next: K8s Pod Security Context