MongoDB is a free and open-source document database. It is classified  as a NoSQL database which is different than traditional table-based SQL  databases like MySQL and PostgreSQL.

In MongoDB, data is stored  in flexible, JSON-like documents where fields can vary from document to  document. It does not require a predefined schema and data structure can  be changed over time.

In  this tutorial, we will show you how to install and configure MongoDB  Community Edition on a CentOS 7 server from the official MongoDB  repositories.

Prerequisites

Before continuing with this tutorial, make sure you are logged in as a user with sudo privileges.

Installing MongoDB

At  the time of writing this article, the latest version of MongoDB  available from the official MongoDB repositories is version 4.0. Before  continuing with the next step visit the Install on Red Hat section of MongoDB’s documentation and check if there is a new release available.

Follow the steps below to install the latest stable version of MongoDB on your CentOS server :

Enabling MongoDB repository

To add the MongoDB repository to your system, open your text editor and create a new YUM repository configuration file named mongodb-org.repo inside the /etc/yum.repos.d/ directory:/etc/yum.repos.d/mongodb-org.repo

[mongodb-org-4.0]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/4.0/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-4.0.asc

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If you want to install an older version of MongoDB, replace each instance of 4.0 with your preferred version.

Installing MongoDB

Now that the repository is enabled you can install the mongodb-org meta-package using the yum utility:

sudo yum install mongodb-org

During the installation yum will prompt you to import the MongoDB GPG key. Type y and hit Enter.

The following packages will be installed on your system as a part of the mongodb-org package:

  • mongodb-org-server - The mongod daemon, and corresponding init scripts and configurations.
  • mongodb-org-mongos - The mongos daemon.
  • mongodb-org-shell - The mongo shell, an interactive JavaScript interface to MongoDB, used  to perform administrative tasks thought the command line.
  • mongodb-org-tools - Contains several MongoDB tools for importing and exporting data, statistics, as well as other utilities.

Starting MongoDB

Once the installation is completed, start the MongoDB daemon and enable it to start on boot by typing:

sudo systemctl start mongod

Verifying MongoDB Installation

To verify the installation we will connect to the MongoDB database server using the mongo tool and print the server version:

mongo

Once you are inside the MongoDB shell type the following command which will display the MongoDB version:

db.version()

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The output will look like the following:

4.0.1

Configuring MongoDB

You can configure your MongoDB instance by editing the /etc/mongod.conf configuration file which is written in YAML.

The  default configuration settings are sufficient in most cases. However,  for production environments we recommend uncommenting the security  section and enabling authorization as shown below:

/etc/mongod.conf

security:
  authorization: enabled

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The authorization option enables Role-Based Access Control (RBAC) that regulates users access to database resources and operations. If  this option is disabled each user will have access to any database and  will be able to execute any action.

After making changes to the MongoDB configuration file, restart the mongod service:

sudo systemctl restart mongod

To find more information about the configuration options available in MongoDB 4.0 visit the Configuration File Options documentation page.

Creating Administrative MongoDB User

If  you enabled the MongoDB authentication, create one administrative  MongoDB user that you will use to access and manage your MongoDB  instance.

First access the mongo shell with:

mongo

Once you are inside the MongoDB shell type the following command to connect to the admin database:

use admin

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switched to db admin

Create a new user named mongoAdmin with the userAdminAnyDatabase role:

db.createUser(
  {
    user: "mongoAdmin", 
    pwd: "changeMe", 
    roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
  }
)

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Successfully added user: {
	"user" : "mongoAdmin",
	"roles" : [
		{
			"role" : "userAdminAnyDatabase",
			"db" : "admin"
		}
	]
}

You can name the administrative MongoDB user as you want.

Exit the mongo shell with:

quit()

CopyTo test the changes, access the mongo shell using the administrative user you have previously created:

mongo -u mongoAdmin -p --authenticationDatabase admin
use admin

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switched to db admin

Now, print the users with:

show users

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{
	"_id" : "admin.mongoAdmin",
	"user" : "mongoAdmin",
	"db" : "admin",
	"roles" : [
		{
			"role" : "userAdminAnyDatabase",
			"db" : "admin"
		}
	],
	"mechanisms" : [
		"SCRAM-SHA-1",
		"SCRAM-SHA-256"
	]
}

You can also try to access the mongo shell without any arguments ( just type mongo) and see if you can list the users using the same commands as above.

Conclusion

You have learned how to install and configure MongoDB 4.0 on your CentOS 7 server.

You can consult The MongoDB 4.0 Manual for more information on this topic.