How to patch a ConfigMap in Kubernetes

Question

Kubernetes ships with a ConfigMap called coredns that lets you specify DNS settings. I want to modify or patch a small piece of this configuration

Answer 1

This will apply the same patch to that single field:

kubectl patch configmap/coredns \
  -n kube-system \
  --type merge \
  -p '{"data":{"upstreamNameservers":"[\"1.1.1.1\", \"1.0.0.1\"]"}}'