13 - DNS
A simple bash script sufficed in configuring deployment of CoreDNS into the Kubernetes cluster.
The script can be found in the GitLab repository: 06-dns-addon.sh
NOTE: The following commands were taken directly from the repository Kubernetes The Hard Way.
#!/usr/bin/env bash
set -euo pipefail
# DNS Addon
# Deploying the DNS cluster addon
# DNS add-on which provides DNS based service discovery, backed by CoreDNS, to applications running inside the Kubernetes cluster.
# The DNS Cluster Add-on
kubectl apply -f https://storage.googleapis.com/kubernetes-the-hard-way/coredns-1.8.yaml
# List the pods created by the kube-dns deployment:
kubectl get pods -l k8s-app=kube-dns -n kube-system
# Verification
# Create a busybox deployment:
kubectl run busybox --image=busybox:1.28 --command -- sleep 3600
List the pod created by the busybox deployment:
kubectl get pods -l run=busybox
# Retrieve the full name of the busybox pod:
POD_NAME=$(kubectl get pods -l run=busybox -o jsonpath="{.items[0].metadata.name}")
#Execute a DNS lookup for the kubernetes service inside the busybox pod:
kubectl exec -ti $POD_NAME -- nslookup kubernetes