Kubernetes: Get Mongo master of replicaset.

kubernetes-get-mongo-master.sh

#!/usr/bin/env bash

# https://gist.github.com/reduardo7/c8ce682f7cb02f90168c5bec23fed53e

################# Get Master Mongo POD #################
# Params:
#   - Environment: uat/prod
#
# Examples:
# ./get-mongo-master.sh prod
# ./get-mongo-master.sh uat
#######################################################

SERVER_ENV=$1

if [ -z "${SERVER_ENV}" ]; then
  echo 'Error! SERVER_ENV is required' >&2
  exit 1
fi

for pod_name in $(kubectl get pods -n=${SERVER_ENV} --template '{{range .items}}{{.metadata.name}}{{"\n"}}{{end}}' | grep 'mongo-rs-mongodb-replicaset-')
  do
    if echo $(kubectl exec -n ${SERVER_ENV} ${pod_name} -- sh -c 'mongo --eval="rs.isMaster().ismaster ? 7111111 : 7222222"') | grep -q '7111111'
      then
        echo ${pod_name}
      fi
  done