# MongoDB Replication Setup by Nayana

> Document Created by: Nayana
> Date: 9-Aug-2021
> Ref setup document : [From Ramesh](https://hackmd.io/qT1FVIzaQXuGEY4fQ4bKjw)

## Ubuntu Details
1) Check Ubuntu version

Command: lsb_release -a

Output:
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 18.04.3 LTS
Release:	18.04
Codename:	bionic

---

## Install Docker
2) Install Docker on Ubuntu machine

[Install docker](https://docs.docker.com/engine/install/ubuntu/#install-using-the-repository)
[Docker Installation Ref from Ramesh](https://hackmd.io/vKk34V79SlSGL0A0Pee_fQ?view#Install-docker)
1. Allow apt to use repository over HTTPS

sudo apt-get update
sudo apt-get install apt-transport-https ca-certificates curl gnupg lsb-release

2. Add Docker’s official GPG key:

 curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo gpg --dearmor -o /usr/share/keyrings/docker-archive-keyring.gpg

3. Setup stable repository

 echo "deb [arch=amd64 signed-by=/usr/share/keyrings/docker-archive-keyring.gpg] https://download.docker.com/linux/ubuntu \
  $(lsb_release -cs) stable" | sudo tee /etc/apt/sources.list.d/docker.list > /dev/null

4. Install docker engine and verify installation

sudo apt-get update
 sudo apt-get install docker-ce docker-ce-cli containerd.io
sudo docker run hello-world

***verify docker version***

 docker --version


---
## Install MongoDB
[MongoDB Installation Reference](https://docs.mongodb.com/manual/tutorial/install-mongodb-on-ubuntu/)
**NOTE: Primary and container MongoDB version should be same**

Step 1:
wget -qO - https://www.mongodb.org/static/pgp/server-5.0.asc | sudo apt-key add -

Step2:
echo "deb [ arch=amd64,arm64 ] https://repo.mongodb.org/apt/ubuntu bionic/mongodb-org/5.0 multiverse" | sudo tee /etc/apt/sources.list.d/mongodb-org-5.0.list

Step 3:
sudo apt-get update

Step 4: Install MongoDB Package
sudo apt-get install -y mongodb-org

Step5: Start MongoDB server
sudo systemctl start mongod

Step 6: Check MongoDB status
sudo systemctl status mongod

---
## Create the in-container MongoDB server suitable for replication set
1) apt update
2) apt install -y vim
3) Create directory mkdir mongo_docker
4) Create default.js file and insert code [default.js](https://gitlab.ieiworld.com/edge-server-docker/mongodb-docker/blob/master/src/default.js)
5) Create docker file => "vi Dockerfile ",
Copy below lines to Dockerfile
> FROM mongo:3.6-xenial
> RUN apt update && apt install -y vim
> ENV MONGO_INITDB_DATABASE dtaDB
> ADD default.js /docker-entrypoint-initdb.d/default.js
> EXPOSE 27017

## Build Docker images & Configure MongoDB
1) Build docker image "mongo:0.1"
`docker build -f Dockerfile -t mongo:0.1 .`

2) Create folder under mongo_docker folder

     mkdir -p sec1/conf
     mkdir -p sec2/conf

Above commands will create folder {/sec1/conf, sec2/conf}
3) Create mongod.conf file

    cp /etc/mongod.conf sec1/conf/
    cp /etc/mongod.conf sec2/conf/

4) Update mongod.conf
Files to update: /etc/mongod.conf, sec1/conf/mongod.conf, sec2/conf/mongod.conf
Update below information

    dbPath : /data/db
    bindIP : 0.0.0.0

## Create Docker container
[Docker container Ref](https://docs.docker.com/engine/reference/commandline/container_run/)

docker run -d --name factory_sec_1 -v /home/test/mongo_docker/sec1/conf:/etc/mongo -v /home/test/mongo_docker/sec1/mongodb:/data/db -p 27018:27017 mongo:0.1 --config /etc/mongo/mongod.conf --logpath /data/db/mongod.log

docker run -d --name factory_sec_2 -v /home/test/mongo_docker/sec2/conf:/etc/mongo -v /home/test/mongo_docker/sec2/mongodb:/data/db -p 27019:27017 mongo:0.1 --config /etc/mongo/mongod.conf --logpath /data/db/mongod.log

#### Access secondary server from host

mongo 127.0.0.1:27018
mongo 127.0.0.1:27019

#### Access the secondary replication servers via the respective containers

docker exec -it factory_sec_1 /bin/bash
docker exec -it factory_sec_2 /bin/bash

#### Change replication setting in primary server

vi  /etc/mongodb.conf

replSet=rs_factory

Restart primary server
` systemctl restart mongodb `

#### Initialize repication set in primary server (mongo shell)

mongo
rs.initiate()

#### Change the repication settings in the secondary servers
Files to update: vi sec1/conf/mongod.conf, sec2/conf/mongod.conf

replication:  
  replSetName: "rs_factory"

#### Restart container

docker restart factory_sec_1
docker restart factory_sec_2

#### Add the secondary servers to the primary server (mongo shell)

mongo

rs.add("127.0.0.1:27018")
rs.add("127.0.0.1:27019")

**Note:** Instead of local IP (127.0.0.1) use public IP(10.9.2.20 like this) to access replication from outside.

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#### Docker and container's useful commands
Check List of docker container

docker ps -a

Restart container

docker restart <container_name>

stop & remove Container

    docker stop <container_name>
    docker rm <container_name>

#### Check list of docker images & Remove docker image

    docker images
    docker rmi <image_name:tag>

#### Check primary mongodb server status

    mongo
    rs.status()

#### Check scondary mongoDB server status

    - Enter into secondary container then fo to mongo shell 
    docker exec -it factory_sec_1 /bin/bash
    mongo
    rs.secondaryOk()   // You can access secondary server db
    

### Check mongodb log file
primary
`vi /var/log/mongodb/mongod.log`

Check in secondary

docker logs -f factory_sec_1
OR
Go to container
i) docker exec -it factory_sec_1 /bin/bash
ii) vi /data/db/mongod.log

### Remove replication set
db.system.replset.remove({})