CODEWITHSUNDEEP
mongodbdatabase
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LikeToCode

Reputation: 767

Setting up MongoDB replica set

I have a fast Windows 7 PC with 8Gb RAM. I want to test this MongoDB replica set: http://www.mongodb.org/display/DOCS/Replica+Sets for my development. I dont want to buy 3 PCs though, as it's kind of expensive. Is there a way to use some kind of technology, like Hyper-V, to be able to set it up? If not, how many PC and what kind should I buy?

Upvotes: 4

Views: 4721

Answers (6)

DragonFire
DragonFire

Reputation: 4082

On Ubuntu 18.04, MongoDb : shell version v4.2.6

In The Terminal (1) (Secure the port using a firewall since we are using 0.0.0.0)

sudo systemctl stop mongod
sudo systemctl status mongod
sudo mongod --auth --port 27017 --dbpath /var/lib/mongodb --replSet rs0 --bind_ip 0.0.0.0

Then open another instance of terminal (2) (Keep the previous one open)

mongo -u yourUserName -p (it will ask for password - follow on)
rs.initiate()

Then open yet another instance of terminal (3) Here you will run server.js with your connection url like this : 

const url = 'mongodb://' + user + ':' + password + 
        '@localhost:27017/?replicaSet=rs0' 

MongoClient.connect(url, { useUnifiedTopology: true, authSource: 'admin' }, 
        function (err, client) {
                if (err) {
                    throw err;
                }
            });

Upvotes: 1

Reyan Chougle
Reyan Chougle

Reputation: 5311

We will configure MongoDB replica set with 3 nodes.

Suposse we have 3 nodes with:

  • hostname Mongodb01, ip address 192.168.1.11 and MongoDB installed with port no 27017
  • hostname Mongodb02, ip address 192.168.1.22 and MongoDB installed with port no 27017
  • hostname Mongodb03, ip address 192.168.1.33 and MongoDB installed with port no 27017

Before initiating with this configuration, ensure that you have below points in place:

  • MongoDB service is installed and running in all the 3 nodes
  • All the 3 nodes are connected to each other via IP Address or Hostname
  • The default port nos 27017 and 28017 (or any other port no you are planning to use) are not blocked by any firewall or antivirus

Now, lets begin with configuration

Step 1: Modify the mongodb.conf file of each node to include replica set information.

replSet = myCluster
rest = true

replSet is the unique name of replica set and all the nodes must have same value for replSet parameter. rest is optional but used to enable rest interface for admin web page.

Step 2: Restart MongoDB service on all the 3 nodes

Step 3: Configure replica set on the node you plan to use as primary. In our case we will execute below commands in Mongodb01's mongo shell

rs.initiate()

Initiates replica set

rs.add("<hostname or ip-address>:<port-no>")

Adds secondary node in replica set.

e.g.; rs.add("Mongodb02:27017") or rs.add("192.168.1.22:27017")

rs.addArb("<hostname or ip-address>:<port-no>")

Adds arbiter node in replica set.

e.g.; rs.addArb("Mongodb03:27017") or rs.add("192.168.1.33:27017")

rs.status()

Checks whether all the nodes are added in the replica set. Other way of checking for the nodes in replica is use following URL in your browser address bar http://<hostname or ip-address>:<port>/_replSet

e.g.; http://localhost:27017/_replSet or http://Mongodb01:27017/_replSet or http://192.168.1.11:27017/_replSet.

This URL is accessible only when you set rest = true in mongodb.conf file

Upvotes: 0

Tetiana
Tetiana

Reputation: 323

There is no use in having replica set at the same single host since this contradicts the terms of redundancy and high availability. If your PC goes down or slows down, your replica set will be ruined or undergo degradation. But for sure it’s not cost-efficient to buy several PCs to evaluate replica set, so you can consider a possible scenario described in MongoDB Replica Set with Master-Slave Replication.

With respect to the number of replica set members, you’re right, the most common topology comprises 3 members, but I would suggest you also adding an Arbiter on the separate host. It is a lightweight process and doesn’t require a lot of resources but it plays an important role in maintaining a quorum in an election of new PRIMARY in case you got an even number of members once PRIMARY fails.

Upvotes: 0

tugberk
tugberk

Reputation: 58434

One super easy way is to set the MongoDB replica set by using Docker.

Within our Docker Host, we can create Docker Network which would give us the isolated DNS resolution across containers. Then we can start creating the MongoDB docker containers. They would initially be unaware of each other. However, we can initialise the replication by connecting to one of the containers and running the replica set initialisation command. Finally, we can deploy our application container under the same docker network.

Check out the MongoDB replica set by using Docker post on how to make this work.

Upvotes: 0

user2775185
user2775185

Reputation: 1197

you can create multiple mongod instances running on the same server on diff. ports.

for configuration and the way replica set works, refer to blog below. this will set up replica set as per the instruction on the same box.

http://pareshbhav.blogspot.com/2014/12/mongdb-replicaset-and-streaming.html

Upvotes: 0

Deep Kapadia
Deep Kapadia

Reputation: 1458

You can run multiple mongod processes on the same machine on different ports and pointing to different data directories and make them a part of the same replicaset.

http://www.mongodb.org/display/DOCS/Starting+and+Stopping+Mongo

mongod --dbpath c:/data1 --port 12345 --replSet foo

mongod --dbpath c:/data2 --port 12346 --replSet foo

and then connect to one of the mongod processes using the mongo console and add initiate the replica set using instructions outlined here:

http://www.mongodb.org/display/DOCS/Replica+Sets+-+Basics

Upvotes: 8

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