Kubernetes Tips and Tricks

A few tips and tricks I’ve come across. Starting off small!

Export Cluster Config from Kubeconfig

Say you have a whole bunch of clusters set in your kubeconfig file and you want to extract one. Just one.

Set your config to that cluster (maybe use kubectx) and do:

kubectl config view --minify --raw > cluster.kubeconfig


Merge Kube Configs

Copy your backup, set an env var pointing to the backup config and the new standalone file, and use config view with the flatten option to produce a new, merged, config file, and finally copy that file back to ~/.kube/config.

$ cp ~/.kube/config ./config-backup 
$ KUBECONFIG=./config-backup:./new-standalone.kubeconfig kubectl config view --flatten > new-kube-config
$ cp new-kube-config ~/.kube/config 

Writing an Operator in Shell!

See the shell operator. Good times!

Troubleshoot DNS

See this k8s doc

kubectl apply -f https://k8s.io/examples/admin/dns/dnsutils.yaml

Make sure you are in the default namespace.

Run a dig command from the pod.

$ kubectl exec -i -t dnsutils -- dig +short google.com