Introduction
This post is about hosting MongoDB replica set cluster with dockerised images.
Steps to create MongoDB replica-set
1. Pull Mongo DB images
I have tested this on Mongo image version 4.
docker pull mongo:42. Create a docker network
docker network create mongo-cluster-devGive any name of network you want. But, this will be referenced later. Keep its name.
3. Run mongo containers
docker run -d --net mongo-cluster-dev -p 27017:27017 --name mongoset1 mongo:4 mongod --replSet mongodb-replicaset --port 27017
docker run -d --net mongo-cluster-dev -p 27018:27018 --name mongoset2 mongo:4 mongod --replSet mongodb-replicaset --port 27018
docker run -d --net mongo-cluster-dev -p 27019:27019 --name mongoset3 mongo:4 mongod --replSet mongodb-replicaset --port 27019We are just running three containers in same network we created above.
4. Need to add them in your /etc/hosts file
Open /etc/hosts
Append in the end of file:
127.0.0.1 mongoset1 mongoset2 mongoset34. Configure ReplicaSet
Need to login to one container, and run command.
docker exec -it mongoset1 mongoIt will open up mongo shell in first container. Copy following, and paste it to that shell.
db = (new Mongo('localhost:27017')).getDB('test')
config={"_id":"mongodb-replicaset","members":[{"_id":0,"host":"mongoset1:27017"},{"_id":1,"host":"mongoset2:27018"},{"_id":2,"host":"mongoset3:27019"}]}
rs.initiate(config)This will give some output, something like this:
{
"ok" : 1,
"$clusterTime" : {
"clusterTime" : Timestamp(1567674525, 1),
"signature" : {
"hash" : BinData(0,"AAAAAAAAAAAAAAAAAAAAAAAAAAA="),
"keyId" : NumberLong(0)
}
},
"operationTime" : Timestamp(1567674525, 1)
}Note the status: “ok” above.
MongoDB connection string to use
mongodb://<hostname>:27017,<hostname>:27018,<hostname>:27019/<Your database name>?replicaSet=mongodb-replicaset
