MongoDB Three Node Cluster with Replicaset for Production

Preface

This post assumes that you have some basic understanding of Docker, Docker Compose, and the key components used in the docker ecosystem. Get up to speed, with the Prepare Your Docker Environment section of Docker docs.

Install Docker
install docker-compose

Create keyfile for authentication

Create folder for storing the keyfile

$ mkdir -p docker-mongo/keyfile-mac && cd docker-mongo//keyfile-mac
Create the keyfile with the openssl and save as mongoKeyFileMac with the following commands

$ openssl rand -base64 741 >> mongoKeyFileMac

$ chmod 400 mongoKeyFileMac

Note: chmod to change file permissions to provide read permissions for the file owner.

To know more about the keyfile creation and permisions based on the Operating system read about create keyfile

Create the docker-compose

Create the docker-compose.yml in three-node-rs directory

$ cd docker-mongo && mkdir single-node-rs && touch docker-compose.yml

Copy the following content and save in docker-compose.yml

  version: "3.9"
  services:
    mongodb:
      image : mongo:6
      container_name: mongodb
      hostname: mongodb
      restart: on-failure
      environment:
        - PUID=1000
        - PGID=1000
        - MONGO_INITDB_ROOT_USERNAME=mongouser
        - MONGO_INITDB_ROOT_PASSWORD=mongopass
        - MONGO_INITDB_DATABASE=mydatabase
        - MONGO_REPLICA_SET_NAME=devrs
        - TZ="UTC"
      volumes:
        - mongodb_data:/data/db
        # Use below line if you are running the container in linux machine
        # - ../keyfile-linux/mongoKeyFileLinux:/opt/keyfile/mongoKeyFileLinux
        # Use below line if you are running the container in linux machine
        - ../keyfile-mac/mongoKeyFileMac:/opt/keyfile/mongoKeyFileMac
      ports:
        - 27017:27017
      healthcheck:
        test: |
          test $$(mongosh --quiet -u mongouser -p mongopass --eval "try { rs.initiate({ _id: 'devrs', members: [{ _id: 0, host: 'mongodb' }] }).ok } catch (_) { rs.status().ok }") -eq 1
        interval: 10s
        start_period: 30s
      command: ["mongod", "--replSet", "devrs", "--bind_ip", "localhost,mongodb",  "--keyFile", "/opt/keyfile/mongoKeyFileMac"]
      #command: "--bind_ip_all --keyFile /opt/keyfile/keyfile --replSet devrs"
  volumes:
    mongodb_data: