replica Set mongo docker-compose

Question

I\'m trying to configure a mongodb replicaSet using docker-compose, but when I stop the master container it seems that it doesn\'t pass to the secondary.

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Answer 1

I had similar problem in setting replica set up in a standalone mongodb service with authentication and here are what I ended up with.

docker-compose.yml:

version: '3.7'

services:
  
  ...

  db:
    image: mongo
    restart: always
    expose:
      - 27017
    environment:
      MONGO_INITDB_DATABASE: ${DATABASE_NAME}
      MONGO_INITDB_ROOT_USERNAME: ${DATABASE_USER}
      MONGO_INITDB_ROOT_PASSWORD: ${DATABASE_PASSWORD}
      MONGO_REPLICA_SET_NAME: ${MONGO_REPLICA_SET_NAME}
    command: ["--replSet", "${MONGO_REPLICA_SET_NAME}", "--bind_ip_all"]
    healthcheck:
      test: test $$(echo "rs.status().ok" | mongo -u $${MONGO_INITDB_ROOT_USERNAME} -p $${MONGO_INITDB_ROOT_PASSWORD} --quiet) -eq 1
      interval: 10s
      start_period: 30s
    volumes:
      - ./db:/data/db
      - ./scripts/set-credentials.sh:/docker-entrypoint-initdb.d/set-credentials.sh

  replica-setup:
    image: mongo
    restart: on-failure
    networks:
      default:
    volumes:
      - ./scripts/setup-replica.sh:/scripts/setup-replica.sh
    entrypoint: [ "bash", "/scripts/setup-replica.sh" ]
    depends_on:
      - db
    environment:
      MONGO_INITDB_ROOT_USERNAME: ${DATABASE_USER}
      MONGO_INITDB_ROOT_PASSWORD: ${DATABASE_PASSWORD}

./scripts/setup-replica.sh:

#!/bin/bash

MONGODB1=db

echo "Waiting for MongoDB startup..."
until curl http://${MONGODB1}:27017/serverStatus\?text\=1 2>&1 | grep uptime | head -1; do
  printf '.'
  sleep 1
done

# check if replica set is already initiated
RS_STATUS=$( mongo --quiet --host ${MONGODB1}:27017 -u $MONGO_INITDB_ROOT_USERNAME -p $MONGO_INITDB_ROOT_PASSWORD --eval "rs.status().ok" )
if [[ $RS_STATUS != 1 ]]
then
  echo "[INFO] Replication set config invalid. Reconfiguring now."
  RS_CONFIG_STATUS=$( mongo --quiet --host ${MONGODB1}:27017 -u $MONGO_INITDB_ROOT_USERNAME -p $MONGO_INITDB_ROOT_PASSWORD --eval "rs.status().codeName" )
  if [[ $RS_CONFIG_STATUS == 'InvalidReplicaSetConfig' ]]
  then
    mongo --quiet --host ${MONGODB1}:27017 -u $MONGO_INITDB_ROOT_USERNAME -p $MONGO_INITDB_ROOT_PASSWORD < /dev/null
  fi
else
  echo "[INFO] Replication set already initiated."
fi

./scripts/set-credentials.sh:

#!/bin/bash
set -e

mongo -- "$MONGO_INITDB_DATABASE" <

What I achieved through is:

• Setup a mongodb service with username/password authentication for a default collection
• Initialize replica set when it's first time running services
• Reconfigure replica set member when there's a previous db data
• Health check the mongodb service by checking replica set status