What steps are necessary to employ Kubernetes DNS for pods?

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There are several steps that are necessary to employ Kubernetes DNS for pods:

1. Verify that the DNS addon is enabled in your Kubernetes cluster. This can be done using the command kubectl get pods --namespace=kube-system.

2. Create a pod that requires DNS resolution by including the appropriate DNS configuration settings in the pod spec. For example, use a YAML file to define a pod like this:

apiVersion: v1
kind: Pod
metadata:
  name: my-dns-pod
spec:
  containers:
  - name: my-container
    image: my-image
    dnsPolicy: Default
    command: ["/bin/sh"]
    args: ["-c", "nslookup kubernetes.default"]

In this example, the dnsPolicy setting is set to default which means that the pod will use the cluster's DNS. The command and args provide a shell command to run in the container, which in this case is to look up the DNS name kubernetes.default.

1. Deploy the pod using the command kubectl create -f my-dns-pod.yaml.

2. Verify that the pod is running and able to successfully resolve DNS names by running the command kubectl logs my-dns-pod.

3. Use DNS names to communicate between pods. For example, if you have two pods named web and database, you could use the DNS names web and database to enable communication between them:

apiVersion: v1
kind: Pod
metadata:
  name: my-web-pod
spec:
  containers:
  - name: web-container
    image: my-web-image
    command: ["/bin/sh"]
    args: ["-c", "ping -c 3 database.default.svc.cluster.local"]

In this example, the ping command is used to send traffic to the database pod using its full DNS name with the .default.svc.cluster.local suffix.