Docker compose for MongoDB ReplicaSet - mongodb

Question

I have been trying to dockerize my spring boot application which depends on redis, kafka and mongodb.
Following is the docker-compose.yml:
version: '3.3'
services:
my-service:
image: my-service
build:
context: ../../
dockerfile: Dockerfile
restart: always
container_name: my-service
environment:
KAFKA_CONFLUENT_BOOTSTRAP_SERVERS: kafka:9092
MONGO_HOSTS: mongodb:27017
REDIS_HOST: redis
REDIS_PORT: 6379
volumes:
- /private/var/log/my-service/:/var/log/my-service/
ports:
- 8080:8090
- 1053:1053
depends_on:
- redis
- kafka
- mongodb
portainer:
image: portainer/portainer
command: -H unix:///var/run/docker.sock
restart: always
container_name: portainer
ports:
- 9000:9000
- 9001:8000
volumes:
- /var/run/docker.sock:/var/run/docker.sock
redis:
image: redis
container_name: redis
restart: always
ports:
- 6379:6379
zookeeper:
image: wurstmeister/zookeeper
ports:
- 2181:2181
container_name: zookeeper
kafka:
image: wurstmeister/kafka
ports:
- 9092:9092
container_name: kafka
environment:
KAFKA_CREATE_TOPICS: "cms.entity.change:1:1" # topic:partition:replicas
KAFKA_ADVERTISED_HOST_NAME: kafka
KAFKA_ZOOKEEPER_CONNECT: zookeeper:2181
KAFKA_ADVERTISED_PORT: 9092
volumes:
- /var/run/docker.sock:/var/run/docker.sock
depends_on:
- "zookeeper"
mongodb:
image: mongo:latest
container_name: mongodb
environment:
MONGO_INITDB_ROOT_USERNAME:
MONGO_INITDB_ROOT_PASSWORD:
ports:
- 27017:27017
volumes:
- ./data/db:/data/db
The issue is that this starts up mongo as a STANDALONE instance. So the APIs in my service that persist data are failing as mongo needs to start as a REPLICA_SET.
How can I edit my docker-compose file to start mongo as a REPLICA_SET?

Answer 1

I had the same issue and ended up on this stackoverflow post.
We had a requirement of using official mongoDB docker image (https://hub.docker.com/_/mongo ) and couldn't use bitnami as suggested in Vahid's answer.
This answer isn't exactly what's needed by the question asked and coming in 6 months too late; but it should give directions to someone who need to use the mongoDb standalone replicaset throw away instance for integration testing purpose. If you need to use it in PROD then you'll have to provide environment variables for volumes and auth as per Vahid's answer.
version: '3.7'
services:
mongodb:
image: mongo:latest
container_name: myservice-mongodb
networks:
- myServiceNetwork
expose:
- 27017
command: --replSet singleNodeReplSet
mongodb-replicaset:
container_name: mongodb-replicaset-helper
depends_on:
- mongodb
networks:
- myServiceNetwork
image: mongo:latest
command: bash -c "sleep 5 && mongo --host myservice-mongodb --port 27017 --eval \"rs.initiate()\" && sleep 2 && mongo --host myservice-mongodb --port 27017 --eval \"rs.status()\" && sleep infinity"
my-service:
depends_on:
- mongodb-replicaset
image: myserviceimage
container_name: myservicecontainer
networks:
- myServiceNetwork
environment:
myservice__Database__ConnectionString: mongodb://myservice-mongodb:27017/?connect=direct&replicaSet=singleNodeReplSet&readPreference=primary
myservice__Database__Name: myserviceDb
networks:
myServiceNetwork:
driver: bridge
NOTE: Please look at the way how connection string is passed as env variable to the service depending on mongo replicaset instance. You'd have to ensure that the name used in setting up the mongodb replicaset (in my case singleNodeReplicaSet) is passed on to the service depending on it.

Answer 2

Edited:
my previous answer was far wrong so I changed it. I managed to make it work using 'bitnami/mongodb:4.0'. Not sure if that would help you or not, but maybe it gives you some idea. They have a docker-compose file ready for replicaset mode.
version: '3'
services:
mdb-primary:
image: 'bitnami/mongodb:4.0'
environment:
- MONGODB_REPLICA_SET_MODE=primary
- MONGODB_ROOT_PASSWORD=somepassword
- MONGODB_REPLICA_SET_KEY=replicasetkey
- MONGODB_ADVERTISED_HOSTNAME=mdb-primary
mdb-secondary:
image: 'bitnami/mongodb:4.0'
depends_on:
- mdb-primary
environment:
- MONGODB_PRIMARY_HOST=mdb-primary
- MONGODB_REPLICA_SET_MODE=secondary
- MONGODB_PRIMARY_ROOT_PASSWORD=somepassword
- MONGODB_REPLICA_SET_KEY=replicasetkey
- MONGODB_ADVERTISED_HOSTNAME=mdb-secondary
mdb-arbiter:
image: 'bitnami/mongodb:4.0'
depends_on:
- mdb-primary
environment:
- MONGODB_PRIMARY_HOST=mdb-primary
- MONGODB_REPLICA_SET_MODE=arbiter
- MONGODB_PRIMARY_ROOT_PASSWORD=somepassword
- MONGODB_REPLICA_SET_KEY=replicasetkey
- MONGODB_ADVERTISED_HOSTNAME=mdb-arbiter
mongo-cli:
image: 'bitnami/mongodb:latest'
don't forget to add volumes and map it to /bitnami on the primary node
the last container, mongo-cli is for testing purposes. So you can connect to the replicaset using the cli, there is an argument about that here if you like to read about it.
$ docker-compose exec mongo-cli bash
$ mongo "mongodb://mdb-primary:27017/test?replicaSet=replicaset"