How to Install pgAdmin 4 on CentOS 8

In this tutorial guide, I will be taking through the installation of pgAdmin 4 version 6.2 on CentOS 8

pgAdmin 4 is a free and open-source management tool for Postgres. Its desktop runtime written in NWjs allows it to run standalone for individual users, or the web applications code may be directly deployed on a web server for use by the web browser.

pgAdmin 4 is a complete rewrite of pgAdmin, built using Python and Java.

New features of pgAdmin 4 version 6.2

The following new features were introduced for the latest release of 6.2. these features are mostly for bug fixes.

• It added support of Aggregate and Operator node in view-only mode
• It ensures that users will be able to modify the REMOTE_USER environment variable as per their environment by introducing the new config parameter WEBSERVER_REMOTE_USER.

You can refer to pgAdmin 4 documentation for more concerning the bug fixes introduced with the current version 6.2.

We need to install PostgreSQL before we can install pgAdmin4. Check this article on how to install PostgreSQL.

• How to Install PostgreSQL 14 on Rocky Linux 8
• How to install PostgreSQL 14 on Ubuntu 20.04/21.04/21.10
• How to install pgAdmin 4 version 6.2 on Ubuntu 21.10

Prerequisites

• Have a user with sudo priviliges
• CentOS 8 server
• Basic knowlege of terminal.

Table of Contents

1. Run system updates
2. Uninstall any pgAdmin4 repo currently installed
3. Set pgAdmin 4 repository
4. Install pgAdmin 4
5. Configure pgAdmin 4 on CentOS 8
6. Conclusion

1. Update CentOS 8 repositories

System updates need to be run every time on a new system, this is in order to make packages up to date. Run the updates using the following command.

$ sudo yum update -y

2. Uninstall pgAdmin 4 repo currently installed

uninstall any pgAdmin 4 currently installed. We can do that like this;

$ sudo rpm -e pgadmin4-redhat-repo

3. Set pgAdmin 4 repository

To add pgAdmin 4 repository, use the following command;

$ sudo yum install https://ftp.postgresql.org/pub/pgadmin/pgadmin4/yum/pgadmin4-redhat-repo-2-1.noarch.rpm

4. Install pgAdmin 4 on CentOS 8

To install pgAdmin 4 both desktop and web modes, run the following command;

$ sudo yum install pgadmin4

Sample output

Installing:
 pgadmin4                   noarch        6.2-1.el8                                       pgAdmin4         6.2 k
Upgrading:
 chkconfig                  x86_64        1.19.1-1.el8                                    baseos           198 k
 platform-python-pip        noarch        9.0.3-20.el8                                    baseos           1.7 M
Installing dependencies:
 apr                        x86_64        1.6.3-12.el8                                    appstream        129 k
 apr-util                   x86_64        1.6.1-6.el8                                     appstream        105 k
 centos-logos-httpd         noarch        85.8-2.el8                                      baseos            75 k
 desktop-file-utils         x86_64        0.23-8.el8                                      appstream         80 k
 emacs-filesystem           noarch        1:26.1-7.el8                                    baseos            70 k
 httpd                      x86_64        2.4.37-43.module_el8.5.0+1022+b541f3b1          appstream        1.4 M
 httpd-filesystem           noarch        2.4.37-43.module_el8.5.0+1022+b541f3b1          appstream         39 k
 httpd-tools                x86_64        2.4.37-43.module_el8.5.0+1022+b541f3b1          appstream        107 k
 libatomic                  x86_64        8.5.0-4.el8_5                                   baseos            24 k
 mailcap                    noarch        2.1.48-3.el8                                    baseos            39 k
 mod_http2                  x86_64        1.15.7-3.module_el8.4.0+778+c970deab            appstream        154 k
 pgadmin4-desktop           x86_64        6.2-1.el8                                       pgAdmin4          80 M
 pgadmin4-server            x86_64        6.2-1.el8                                       pgAdmin4          87 M
 pgadmin4-web               noarch        6.2-1.el8                                       pgAdmin4         8.6 k
 postgresql14-libs          x86_64        14.1-1PGDG.rhel8                                pgAdmin4         274 k
 python3-mod_wsgi           x86_64        4.6.4-4.el8                                     appstream        2.5 M
 python3-pip                noarch        9.0.3-20.el8                                    appstream         20 k
 python3-setuptools         noarch        39.2.0-6.el8                                    baseos           163 k
 python36                   x86_64        3.6.8-38.module_el8.5.0+895+a459eca8            appstream         19 k
 xdg-utils                  noarch        1.1.2-5.el8                                     appstream         84 k
Installing weak dependencies:
 apr-util-bdb               x86_64        1.6.1-6.el8                                     appstream         25 k
 apr-util-openssl           x86_64        1.6.1-6.el8                                     appstream         27 k
Enabling module streams:
 httpd                                    2.4                                                                   
 python36                                 3.6    

5. Configure pgAdmin 4 on CentOS 8

We need to serve our pgadmin 4 using an Apache webserver. First, enable it to start on boot

$ sudo systemctl start httpd 

If you are getting the error message “Failed to start httpd.service: Unit httpd.service not found.” please install httpd into your system.

$ sudo yum install httpd -y

Then go ahead and start the http service.

Also make sure you enable the service to run every time you boot your machine.

$ sudo systemctl enable httpd

You can check the status with the following command;

$ sudo systemctl status httpd

If the service status is active then it’s good to continue.

● httpd.service - The Apache HTTP Server
   Loaded: loaded (/usr/lib/systemd/system/httpd.service; enabled; vendor preset: disabled)
   Active: active (running) since Mon 2021-11-29 15:56:36 UTC; 2min 56s ago
     Docs: man:httpd.service(8)
 Main PID: 72868 (httpd)
   Status: "Running, listening on: port 80"
    Tasks: 213 (limit: 4763)
   Memory: 25.1M
   CGroup: /system.slice/httpd.service
           ├─72868 /usr/sbin/httpd -DFOREGROUND
           ├─72869 /usr/sbin/httpd -DFOREGROUND
           ├─72870 /usr/sbin/httpd -DFOREGROUND
           ├─72871 /usr/sbin/httpd -DFOREGROUND
           └─72872 /usr/sbin/httpd -DFOREGROUND

Nov 29 15:56:36 centos-8 systemd[1]: Starting The Apache HTTP Server...
Nov 29 15:56:36 centos-8 httpd[72868]: AH00558: httpd: Could not reliably determine the server's fully qualified>
Nov 29 15:56:36 centos-8 systemd[1]: Started The Apache HTTP Server.
Nov 29 15:56:36 centos-8 httpd[72868]: Server configured, listening on: port 80

Let’s now run the web setup script so that we can configure the system to run in web mode.

$ sudo /usr/pgadmin4/bin/setup-web.sh

Sample output

Setting up pgAdmin 4 in web mode on a Redhat based platform...
Creating configuration database...
NOTE: Configuring authentication for SERVER mode.

Enter the email address and password to use for the initial pgAdmin user account:

Email address: [email protected]
Password: 
Retype password:
pgAdmin 4 - Application Initialisation
======================================

Creating storage and log directories...
Configuring SELinux...
The Apache web server is running and must be restarted for the pgAdmin 4 installation to complete. Continue (y/n)? y
Apache successfully restarted. You can now start using pgAdmin 4 in web mode at http://127.0.0.1/pgadmin4

Open your favorite browser and paste http://<Your_IP_Address>/pgadmin4 to open pgadmin 4

6. Conclusion

We have installed pgAdmin 4 on our CentOS 8 successfully. Continue exploring by adding new servers then connecting with the databases in order to know more.