How to Create MongoDB cluster as Docker Containers - mongodb

Question

I can able to run single instance on Mongo using the following Docker command
docker run -it --rm -d -p 27017:27017 --user mongodb mongo:3.4
But I can't find out how to configure Config Server and Query Router and also how add shards with Replication
Thanks in Advance

Answer 1

I used this tutorial myself: https://medium.com/#gargar454/deploy-a-mongodb-cluster-in-steps-9-using-docker-49205e231319#.mle6a8wmg
Step 1: create folders
create folders (local on all nodes):
sudo mkdir -p /dockerlocalstorage/data/mongodb
sudo mkdir -p /dockerlocalstorage/backup/mongodb
sudo mkdir -p /dockersharedstorage/config/mongodb/
Step 2: create keyfile
create keyfile as root user and give correct permissions:
sudo su
cd /dockersharedstorage/config/mongodb/
openssl rand -base64 741 > mongodb-keyfile
chmod 600 mongodb-keyfile
sudo chown 999 mongodb-keyfile
Depending on the mount type you might need to use /dockerlocalstorage/ to keep the certs. Mongodb will complain if the permissions are not set correctly (which could be harder to achieve on lets say a cifs mount)
Step 3: setup first node
create mongodb container without auth/keyfile:
docker run --name mongodb \
-v /dockerlocalstorage/data/mongodb:/data/db \
-v /dockersharedstorage/config/mongodb:/opt/keyfile \
--hostname="dock01" \
-p 27017:27017 \
-d mongo
log in to container:
docker exec -it mongodb mongo
create root users, dont forget to change the passwords
use admin
db.createUser( {
user: "admin",
pwd: "PASSWORD",
roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
});
db.createUser( {
user: "root",
pwd: "PASSWORD",
roles: [ { role: "root", db: "admin" } ]
});
exit and remove the container
exit
docker stop mongodb
docker rm mongodb
Step 4: start nodes
change NODE_NR:
docker run \
-d \
--name mongodb \
-v /dockerlocalstorage/data/mongodb:/data/db \
-v /dockerlocalstorage/backup/mongodb:/data/backup \
-v /dockersharedstore/config/mongodb:/opt/keyfile \
--restart=always \
--hostname="dock01" \
-p 27017:27017 mongo \
--keyFile /opt/keyfile/mongodb-keyfile \
--replSet "SET_NAME"
Step 5: setup replication
connect to node 1:
docker exec -it mongodb mongo
use admin
db.auth("root", "PASSWORD");
initialize the replication set:
rs.initiate()
Check the replica set with: rs.conf() or rs.status()
add others:
rs.add("dock02:27017")
rs.add("dock03:27017")
Step 6: setup mongodump
edit crontab:
sudo su
crontab -l > tempcron
echo new cron into cron file
echo "0 4 * * * docker exec -it mongodb mongodump -u root -p PASSWORD -o /data/backup/daily" >> tempcron
echo "30 4 * * 5 docker exec -it mongodb mongodump -u root -p PASSWORD -o /data/backup/weekly" >> tempcron
install new cron file
crontab tempcron
rm tempcron
exit

Answer 2

You could use docker swarm mode if you want docker native mongodb cluster (Docker >= 1.12 needed).
Have a look at this nice tutorial. This will show you how to get a mongodb cluster with docker, replicated with Config Server. Basically, the steps are:
Create multiple virtual machines (with docker-machine or whatever you use to create a new docker host)
Create the swarm (docker cluster of multiple machines)
Create a swarm overlay network to deal with all your mongodb traffic
Create the services on each swarm node (that will create your mongodb containers on your hosts)
Configure your mongodb replica set
This is a bit of work, but worth it, as when you get there, you'll have tools on docker swarm to orchestrate your mongodb cluster.