Repository Management

Applies to CentOS Stream 9 & 10 / AlmaLinux 9.x & 10.x / Rocky Linux 9.x & 10.x

Software repositories are the sources from which DNF obtains packages. Properly managing repositories is a fundamental system administration skill — you need to know which repositories are configured on your system, how to add new ones, and how to control repository priority.

What You Will Learn

• View and manage configured repositories
• Enable and disable repositories
• Add third-party repositories
• The structure of .repo files
• Configure repository priorities
• Use dnf config-manager

Prerequisites

• A system with EL 9.x / 10.x installed
• A user account with sudo privileges
• The system is connected to the internet
• Familiarity with DNF Basics

Viewing Repositories

List Enabled Repositories

View currently enabled repositories

$ dnf repolist

Example output:

repo id                         repo name
appstream                       AlmaLinux 9 - AppStream
baseos                          AlmaLinux 9 - BaseOS
extras                          AlmaLinux 9 - Extras

List All Repositories (Including Disabled)

View all repositories

$ dnf repolist all

Example output:

repo id                      repo name                          status
appstream                    AlmaLinux 9 - AppStream            enabled
appstream-debug              AlmaLinux 9 - AppStream - Debug    disabled
appstream-source             AlmaLinux 9 - AppStream - Source   disabled
baseos                       AlmaLinux 9 - BaseOS               enabled
baseos-debug                 AlmaLinux 9 - BaseOS - Debug       disabled
baseos-source                AlmaLinux 9 - BaseOS - Source      disabled
crb                          AlmaLinux 9 - CRB                  disabled
extras                       AlmaLinux 9 - Extras               enabled

View Repository Details

View detailed information about a repository

$ dnf repoinfo baseos

Example output:

Repo-id            : baseos
Repo-name          : AlmaLinux 9 - BaseOS
Repo-status        : enabled
Repo-revision      : 1711234567
Repo-updated       : Mon 24 Mar 2026 08:00:00 AM CST
Repo-pkgs          : 1,842
Repo-available-pkgs: 1,842
Repo-size          : 1.5 G
Repo-baseurl       : https://repo.almalinux.org/almalinux/9/BaseOS/x86_64/os/
Repo-expire        : 86,400 second(s) (last: Mon 24 Mar 2026 10:15:00 AM CST)
Repo-filename      : /etc/yum.repos.d/almalinux-baseos.repo

.repo File Structure

All repository configuration files are stored in the /etc/yum.repos.d/ directory with a .repo extension.

List repo configuration files

$ ls /etc/yum.repos.d/

A typical .repo file looks like this:

/etc/yum.repos.d/almalinux-baseos.repo example

[baseos]
name=AlmaLinux $releasever - BaseOS
baseurl=https://repo.almalinux.org/almalinux/$releasever/BaseOS/$basearch/os/
enabled=1
gpgcheck=1
countme=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-AlmaLinux-9
metadata_expire=86400

Field descriptions:

Field	Description
[baseos]	Repository ID, a unique identifier
name	Repository name, used for display purposes only
baseurl	The URL of the repository
mirrorlist	Mirror list URL (use either this or baseurl)
enabled	1 to enable, 0 to disable
gpgcheck	1 to enable GPG signature verification, 0 to disable
gpgkey	Path to the GPG public key
metadata_expire	Metadata expiration time (in seconds)
priority	Repository priority (requires dnf-plugins-core)

Tip

$releasever and $basearch are DNF variables representing the system version (e.g., 9) and architecture (e.g., x86_64) respectively. DNF substitutes them automatically.

Enabling and Disabling Repositories

Using dnf config-manager

Both EL 9 and EL 10 use DNF 4 (EL 10 ships 4.20), so the config-manager syntax is the same:

Disable a repository

$ sudo dnf config-manager --set-disabled crb

Enable a repository

$ sudo dnf config-manager --set-enabled crb

Verify the change

$ dnf repolist | grep crb
crb                             AlmaLinux 9 - CRB

Note

The CRB (CodeReady Builder) repository contains development libraries and headers. Many EPEL packages depend on it. If you plan to enable EPEL, you typically need to enable CRB as well.

Temporarily Enabling/Disabling Repositories

If you only want to use a repository for a single operation without modifying the configuration:

Temporarily enable a repository to install a package

$ sudo dnf install --enablerepo=crb some-devel-package

Temporarily disable a repository

$ sudo dnf update --disablerepo=epel

Adding Third-Party Repositories

Method 1: Install a Repository RPM Package

Most well-known third-party repositories provide RPM packages that automatically configure the repository:

Using EPEL as an example

$ sudo dnf install epel-release

This will automatically create the corresponding .repo file under /etc/yum.repos.d/ and import the GPG key.

Method 2: Use dnf config-manager

Add a repository URL directly

$ sudo dnf config-manager --add-repo https://example.com/repo/el9/example.repo

This downloads the remote .repo file to /etc/yum.repos.d/.

Method 3: Manually Create a .repo File

1. Create the .repo file

   Create a custom repository configuration

   $ sudo vi /etc/yum.repos.d/my-custom.repo

   Enter the following content:

   [my-custom-repo]
   name=My Custom Repository
   baseurl=https://repo.example.com/el9/$basearch/
   enabled=1
   gpgcheck=1
   gpgkey=https://repo.example.com/RPM-GPG-KEY-example

2. Refresh the cache

   Clear and rebuild the cache

   $ sudo dnf clean all
   $ sudo dnf makecache

3. Verify the repository is active

   Confirm the new repository appears in the list

   $ dnf repolist

Caution

When manually adding a repository, always enable gpgcheck=1 and configure the correct gpgkey. Disabling GPG checks means you trust any package in the repository, which poses a security risk.

Repository Priority

When multiple repositories provide packages with the same name, you can use priorities to control which repository DNF prefers.

1. Ensure dnf-plugins-core is installed

   Install the DNF plugin package

   $ sudo dnf install -y dnf-plugins-core

2. Edit the repository configuration file and add the priority field

   Edit the repository file

   $ sudo vi /etc/yum.repos.d/epel.repo

   Add the following under the [epel] section:

   priority=10

Priority rules:

• Lower numbers mean higher priority
• The default priority is 99
• It is recommended to keep official repositories at the default or a high priority, and set third-party repositories to a lower priority

Repository	Recommended Priority
baseos / appstream	10 (default is fine)
EPEL	20
Other third-party repositories	30 or higher

Tip

Priority configuration prevents third-party repository packages from overriding official repository packages. This is an important security measure when using third-party repositories.

dnf config-manager Command Summary

EL 9 and EL 10 (DNF 4.20) use the same syntax:

View a repository's configuration

$ dnf config-manager --dump baseos

Set an option for a repository

$ sudo dnf config-manager --save --setopt=epel.priority=20

Add a remote repository file

$ sudo dnf config-manager --add-repo https://example.com/repo.repo

Enable a repository

$ sudo dnf config-manager --set-enabled <repo-id>

Disable a repository

$ sudo dnf config-manager --set-disabled <repo-id>

Common Issues

”Cannot find a valid baseurl for repo”

This is typically a network issue or an invalid repository URL:

Check network connectivity

$ curl -I https://repo.almalinux.org/

If using a mirrorlist, check if DNS is working properly

$ dig mirrorlist.centos.org

If using a server in China, you may need to switch to a domestic mirror.

Using Domestic Mirrors (China)

Using Alibaba Cloud mirrors as an example, edit the corresponding .repo file and replace the baseurl with the Alibaba Cloud address:

Back up the original configuration

$ sudo cp /etc/yum.repos.d/almalinux-baseos.repo /etc/yum.repos.d/almalinux-baseos.repo.bak

Caution

Always back up the original .repo files before modifying repository URLs. If the mirror encounters issues, you can restore them quickly.

”GPG check FAILED”

The repository’s GPG key may not have been imported:

Manually import a GPG key

$ sudo rpm --import https://repo.example.com/RPM-GPG-KEY-example

View imported GPG keys

$ rpm -qa gpg-pubkey*

Further Reading

• DNF Package Management Basics — Everyday package management operations
• EPEL and Third-Party Repositories — Install and use EPEL
• RPM Basics — Low-level package management tool
• man dnf.conf — Detailed DNF configuration file reference
• man yum.conf — Repository configuration file format reference