Installing and Configuring MongoDB on CentOS 7

by · April 25, 2018

Installing and Configuring MongoDB

MongoDB is a NoSQL database that provides high performance, high availability, and automatic scaling. NoSQL database means that, unlike MySQL or PostgreSQL, it does not support SQL (Structured Query Language) to retrieve or manipulate the stored data.

Installing and Configuring MongoDB

MongoDB does not store data in tables, instead, it stores data in a “document” structure similar to JSON (in MongoDB called BSON). MongoDB was first introduced in 2009, six years ago. Currently developed by the company MongoDB MongoDB Inc.

In this tutorial, we will guide you to install and configure MongoDB on a CentOS 7.3 server. We will add and configure the administrator user for MongoDB and configure the authentication for MongoDB services.

Prerequisites

  • CentOS 7.3 (Operating system used here)
  • root privileges.

Step 1: Adding MongoDB Repository in CentOS

After logged into your server’s ssh as root user, go to the ‘yum.repos.d’ directory in order to add the new CentOS repository. Go to that directory and create new repository file ‘mongodb-org-3.2.repo’

[root@webhostingchennai ~]# cd /etc/yum.repos.d/
[root@webhostingchennai ~]# nano mongodb-org-3.2.repo

Paste MongoDB repository configuration as below

[mongodb-org-3.2]
name=MongoDB Repository
baseurl=https://repo.mongodb.org/yum/redhat/$releasever/mongodb-org/3.2/x86_64/
gpgcheck=1
enabled=1
gpgkey=https://www.mongodb.org/static/pgp/server-3.2.asc

And now save the file and exit.

Step 2 : Installing MongoDB

Now check the repository list on the server to make sure that the MongoDB repository is available in the list.

Run the below command

You should see results below. The MongoDB repository is on the list.

[root@webhostingchennai yum.repos.d]# yum repolist
Loaded plugins: fastestmirror
base                                             | 3.6 kB  00:00:00
centosplus                                       | 3.4 kB  00:00:11
epel/x86_64/metalink                             | 7.6 kB  00:00:00
epel                                             | 4.7 kB  00:00:00
extras                                           | 3.4 kB  00:00:00
mongodb-org-3.2                                  | 2.5 kB  00:00:00
updates                                          | 3.4 kB  00:00:00
(1/3): mongodb-org-3.2/7/primary_db              |  82 kB  00:00:01
(2/3): epel/x86_64/updateinfo                    | 917 kB  00:00:01
(3/3): epel/x86_64/primary_db                    | 6.3 MB  00:00:14
Loading mirror speeds from cached hostfile
 * base: centos.excellmedia.net
 * centosplus: centos.excellmedia.net
 * epel: mirror.nes.co.id
 * extras: centos.excellmedia.net
 * updates: centos.excellmedia.net
repo id                                 repo name                                       status
base/7/x86_64                           CentOS-7 - Base                                 9,566+25
centosplus/7/x86_64                     CentOS-7 - Plus                                 71+21
epel/x86_64                             Extra Packages for Enterprise Linux 7 - x86_64  12,509
extras/7/x86_64                         CentOS-7 - Extras                               448
mongodb-org-3.2/7                       MongoDB Repository                              100
updates/7/x86_64                        CentOS-7 - Updates                              2,323+93
repolist: 25,017
[root@webhostingchennai yum.repos.d]#

Next, we need to install MongoDB with the yum command.

yum -y install mongodb-org

After completion of the installation, start MongoDB with this systemctl command

systemctl start mongod

Check that MongoDB is running by checking that the port ‘27017’ is open.

netstat -plntu

And make sure the mongodb service is active.

systemctl status mongod
[root@webhostingchennai yum.repos.d]# systemctl start mongod
[root@webhostingchennai yum.repos.d]# netstat -plntu
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name
tcp        0      0 127.0.0.1:27017         0.0.0.0:*               LISTEN      28670/mongod
tcp        0      0 0.0.0.0:8080            0.0.0.0:*               LISTEN      21442/monitorix-htt
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      19700/sshd
tcp        0      0 127.0.0.1:25            0.0.0.0:*               LISTEN      745/master
tcp6       0      0 :::22                   :::*                    LISTEN      19700/sshd
udp        0      0 103.14.121.94:123       0.0.0.0:*                           19862/ntpd
udp        0      0 127.0.0.1:123           0.0.0.0:*                           19862/ntpd
udp        0      0 0.0.0.0:123             0.0.0.0:*                           19862/ntpd
udp6       0      0 fe80::216:3eff:fed0:123 :::*                                19862/ntpd
udp6       0      0 ::1:123                 :::*                                19862/ntpd
udp6       0      0 :::123                  :::*                                19862/ntpd
[root@webhostingchennai yum.repos.d]# systemctl status mongod
● mongod.service - SYSV: Mongo is a scalable, document-oriented database.
   Loaded: loaded (/etc/rc.d/init.d/mongod; bad; vendor preset: disabled)
   Active: active (running) since Wed 2018-04-25 13:54:15 EEST; 20s ago
     Docs: man:systemd-sysv-generator(8)
  Process: 28655 ExecStart=/etc/rc.d/init.d/mongod start (code=exited, status=0/SUCCESS)
   CGroup: /system.slice/mongod.service
           └─28670 /usr/bin/mongod -f /etc/mongod.conf

Apr 25 13:54:14 webhostingchennai.com systemd[1]: Starting SYSV: Mongo is a scalable, document-oriented database....
Apr 25 13:54:15 webhostingchennai.com runuser[28666]: pam_unix(runuser:session): session opened for user mongod ...d=0)
Apr 25 13:54:15 webhostingchennai.com runuser[28666]: pam_unix(runuser:session): session closed for user mongod
Apr 25 13:54:15 webhostingchennai.com mongod[28655]: Starting mongod: [  OK  ]
Apr 25 13:54:15 webhostingchennai.com systemd[1]: Started SYSV: Mongo is a scalable, document-oriented database..
Hint: Some lines were ellipsized, use -l to show in full.
[root@webhostingchennai yum.repos.d]#

Step 3 : Fix a MongoDB Error

MongoDB is installed. Now we can access the mongodb shell by using the command below:

mongo

You will probably see this error about ulimit configuration on the server.

** WARNING: soft rlimits too low. rlimits set to 4096 processes, 64000 files. Number of processes should be at least 32000…

[root@webhostingchennai yum.repos.d]# mongo
MongoDB shell version: 3.2.19
connecting to: test
Welcome to the MongoDB shell.
For interactive help, type "help".
For more comprehensive documentation, see
        http://docs.mongodb.org/
Questions? Try the support group
        http://groups.google.com/group/mongodb-user
Server has startup warnings:
2018-04-25T13:54:15.753+0300 I CONTROL  [initandlisten]
2018-04-25T13:54:15.753+0300 I CONTROL  [initandlisten] ** WARNING: soft rlimits too low. rlimits set to 4096 processes, 64000 files. Number of processes should be at least 32000 : 0.5 times number of files.
>

Ulimits or User limits define how much of a system-wide resource a user may use.

In order to resolve this problem, we need to increase the ulimit configuration of the user mongod.

On CentOS 7 server, the MongoDB database is running under the user ‘mongod’.

Go to the /etc/security/ limits.conf configuration file.

cd /etc/security/
nano limits.conf

Increase the limits of the mongod user to ‘64000’ – number of processes or nproc and the number of open files or nofile to 64000.

Paste new configuration below to the end of the file:

mongod soft nproc 64000
mongod hard nproc 64000
mongod soft nofile 64000
mongod hard nofile 64000

Save the file and exit

Run the sysctl command below to apply the changed limits to the system:

sysctl -p

Now, restart the MongoDB service and try again to access the mongo shell, the error is gone now.

systemctl restart mongod
mongo
[root@webhostingchennai security]# systemctl restart mongod
[root@webhostingchennai security]# mongo
MongoDB shell version: 3.2.19
connecting to: test
>

 

Step 4 : Create a MongoDB Administrator User

In this step, we will create a new user “admin” for MongoDB with the role ‘UserAdminAnyDatabase’ from the mongo shell.

Open the mongodb shell using “mongo” command

Here, I’m creating a new user administrator named ‘admin’ with password ‘mongoadmin’. Use a secure password on your server. Then we will configure the role of the user to be ‘UserAdminAnyDatabase’.

Switch to the database ‘admin’.

use admin

Type in the MongoDB query below to create the new administrator user

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

Next, ensure that the user has been created with the MongoDB query below.

show users

 

[root@webhostingchennai ]# mongo
MongoDB shell version: 3.2.19
connecting to: test
> use admin
switched to db admin
> db.createUser(
...   {
...     user: "admin",
...     pwd: "admin123",
...     roles: [ { role: "userAdminAnyDatabase", db: "admin" } ]
...   }
... )
Successfully added user: {
        "user" : "admin",
        "roles" : [
                {
                        "role" : "userAdminAnyDatabase",
                        "db" : "admin"
                }
        ]
}
> show users
{
        "_id" : "admin.admin",
        "user" : "admin",
        "db" : "admin",
        "roles" : [
                {
                        "role" : "userAdminAnyDatabase",
                        "db" : "admin"
                }
        ]
}
> ^C
bye
[root@webhostingchennai ]#

The MongoDB administrator user has been created.

Step 5 : Enable User Authentication in MongoDB

Here, we will enable authentication for users to prevent that another user without sufficient privileges is able to see the data on the database.

On our CentOS 7 server, MongoDB is running under systemd with an init script in the ‘/etc/init.d/’ dirctory. We will edit that script to force the mongodb service to run with the ‘–auth’ option.

Go to the ‘/etc/init.d/’ directory and edit the “mongod” file

cd /etc/init.d/
nano mongod

On line 15 you will find the “OPTION” variable, there we will add the “mongod” option.

OPTIONS=” –auth -f $CONFIGFILE”

Save the file.

Reload the systemd service and restart MongoDB.

systemctl daemon-reload
systemctl restart mongod

Next, we have to test the configuration by logging into the mongo shell and switch to the admin database, then try to see the admin users.

mongo

use admin
show users

You will see an error about the unauthorized execution of the command in the database admin. Now we need to use the command ‘db.auth()’ for the authentication.

db.auth('admin', 'admin123')

Now you can see the users with their roles and the privileges.

[root@webhostingchennai init.d]# mongo
MongoDB shell version: 3.2.19
connecting to: test
> use admin
switched to db admin
> show users
2018-04-25T14:20:22.249+0300 E QUERY    [thread1] Error: not authorized on admin to execute command { usersInfo: 1.0 } :
_getErrorWithCode@src/mongo/shell/utils.js:25:13
DB.prototype.getUsers@src/mongo/shell/db.js:1523:1
shellHelper.show@src/mongo/shell/utils.js:764:9
shellHelper@src/mongo/shell/utils.js:671:15
@(shellhelp2):1:1

> db.auth('admin', 'mongoadmin')
1
> show users
{
        "_id" : "admin.admin",
        "user" : "admin",
        "db" : "admin",
        "roles" : [
                {
                        "role" : "userAdminAnyDatabase",
                        "db" : "admin"
                }
        ]
}
>

Now, MongoDB 3.2 has been installed and configured on a CentOS 7 Server.

For installing LAMP on Centos 7, click here

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