I have setup Kubernetes HA cluster with 3 masters. Version 1.14.2. Observed that 2 coredns containers are running on only one master. If I stop this Master, coredns is stopped. Are there any configuration to spawn this to remaining masters?
How can I spawn the coredns containers to the remaining masters.
you need to deploy dns autoscaler. and then tune autoscale parameters. follow the link https://kubernetes.io/docs/tasks/administer-cluster/dns-horizontal-autoscaling/
follow the steps
kubectl apply -f https://raw.githubusercontent.com/epasham/docker-repo/master/k8s/dns-horizontal-autoscaler.yaml
kubectl get deployment --namespace=kube-system
kubectl edit configmap dns-autoscaler --namespace=kube-system
Look for this line:
linear: '{"coresPerReplica":256,"min":1,"nodesPerReplica":16}'
updae min value to 2 as shown below
kubectl edit configmap dns-autoscaler --namespace=kube-system
linear: '{"coresPerReplica":256,"min":2,"nodesPerReplica":16}'
you should get two coredns pods listed as below
master $ kubectl get po --namespace=kube-system|grep dns
coredns-78fcdf6894-l54db 1/1 Running 0 1h
coredns-78fcdf6894-vbk6q 1/1 Running 0 1h
dns-autoscaler-6f888f5957-fwpgl 1/1 Running 0 2m