mongodb - 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.

redis:
 image: redis
 ports:
  - "6379:6379"

mongo3:
 hostname: mongo3
 image: mongo
 entrypoint: [ "/usr/bin/mongod", "--replSet", "rs", "--journal","--dbpath","/data/db","--smallfiles", "--rest" ]
 volumes:
  - ./data/mongo3:/data/db
 ports:
  - "27018:27017"
  - "28018:28017"
 restart: always

mongo2:
 hostname: mongo2
 image: mongo
 entrypoint: [ "/usr/bin/mongod", "--replSet", "rs", "--journal","--dbpath","/data/db","--smallfiles", "--rest" ]
 volumes:
  - ./data/mongo2:/data/db
 ports:
  - "27019:27017"
  - "28019:28017"
 restart: always

mongo1:
 hostname: mongo1
 image: mongo
 entrypoint: [ "/usr/bin/mongod", "--replSet", "rs", "--journal","--dbpath","/data/db","--smallfiles", "--rest" ]
 volumes:
  - ./data/mongo1:/data/db
ports:
  - "27017:27017"
  - "28017:28017"
links:
 - mongo2:mongo2
 - mongo3:mongo3
restart: always

web:
 build: .
 ports:
  - "2000:2000"
 volumes:
  - .:/vip
 links:
  - redis
  - mongo1
  - mongo2
  - mongo3

nginx:
 restart: always
 build: ./nginx/
 ports:
  - "80:80"
 links:
  - web:web

mongosetup:
 image: mongo
 links:
  - mongo1:mongo1
  - mongo2:mongo2
  - mongo3:mongo3
 volumes:
  - ./scripts:/scripts
 entrypoint: [ "/scripts/setup.sh" ]

setup.sh :

#!/bin/bash

MONGODB1=`ping -c 1 mongo1 | head -1  | cut -d "(" -f 2 | cut -d ")" -f 1`
MONGODB2=`ping -c 1 mongo2 | head -1  | cut -d "(" -f 2 | cut -d ")" -f 1`
MONGODB3=`ping -c 1 mongo3 | head -1  | cut -d "(" -f 2 | cut -d ")" -f 1`

echo "**********************************************" ${MONGODB1}
echo "Waiting for startup.."
until curl http://${MONGODB1}:28017/serverStatus?text=1 2>&1 | grep uptime | head -1; do
  printf '.'
  sleep 1
done

echo curl http://${MONGODB1}:28017/serverStatus?text=1 2>&1 | grep uptime | head -1
echo "Started.."


echo SETUP.sh time now: `date +"%T" `
mongo --host ${MONGODB1}:27017 <<EOF
var cfg = {
    "_id": "rs",
    "version": 1,
    "members": [
        {
            "_id": 0,
            "host": "${MONGODB1}:27017",
            "priority": 2
        },
        {
            "_id": 1,
            "host": "${MONGODB2}:27017",
            "priority": 0
        },
        {
            "_id": 2,
            "host": "${MONGODB3}:27017",
            "priority": 0
        }
    ],settings: {chainingAllowed: true}
};
rs.initiate(cfg, { force: true });
rs.reconfig(cfg, { force: true });
rs.slaveOk();
db.getMongo().setReadPref('nearest');
db.getMongo().setSlaveOk(); 
EOF

Answer 1

I had a similar issue and resolved it with the following compose file:

version: "3.8"

services:
  mongo1:
    image: mongo:4.2
    container_name: mongo1
    command: ["--replSet", "my-replica-set", "--bind_ip_all", "--port", "30001"]
    volumes:
      - ./data/mongo-1:/data/db
    ports:
      - 30001:30001
    healthcheck:
      test: test $$(echo "rs.initiate({_id:'my-replica-set',members:[{_id:0,host:"mongo1:30001"},{_id:1,host:"mongo2:30002"},{_id:2,host:"mongo3:30003"}]}).ok || rs.status().ok" | mongo --port 30001 --quiet) -eq 1
      interval: 10s
      start_period: 30s

  mongo2:
    image: mongo:4.2
    container_name: mongo2
    command: ["--replSet", "my-replica-set", "--bind_ip_all", "--port", "30002"]
    volumes:
      - ./data/mongo-2:/data/db
    ports:
      - 30002:30002

  mongo3:
    image: mongo:4.2
    container_name: mongo3
    command: ["--replSet", "my-replica-set", "--bind_ip_all", "--port", "30003"]
    volumes:
      - ./data/mongo-3:/data/db
    ports:
      - 30003:30003

with the following in my /etc/hosts file:

127.0.0.1       mongo1
127.0.0.1       mongo2
127.0.0.1       mongo3

I documented it in a GitHub repo and with a little blog post here:

https://github.com/UpSync-Dev/docker-compose-mongo-replica-set

https://www.upsync.dev/2021/02/02/run-mongo-replica-set.html