$ DOCKER_USERNAME=***
$ DOCKER_PASSWORD=***
$ kubectl create secret docker-registry registry-credentials \
--namespace default \
--docker-username=$DOCKER_USERNAME \
--docker-password=$DOCKER_PASSWORD
$ kubectl patch serviceaccount default --namespace default \
-p "{\"imagePullSecrets\": [{\"name\": \"registry-credentials\"}]}"
$ kubectl delete secret --namespace default registry-credentials
$ kubectl patch serviceaccount default --namespace default \
-p "{\"imagePullSecrets\": []}"