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In this lesson you will learn how DNF uses repositories on Red Hat Enterprise Linux 10 (RHEL 10), how to view and manage repository configuration, and how to create and use a custom repository. Most software on RHEL 10 is distributed as RPM packages and managed with DNF.
A dark presentation slide titled "Software Management on RHEL 10" showing two rounded boxes: one labeled "RHEL 10" with a server icon and an arrow pointing to another labeled "RPM" with a package icon.
Historically administrators used YUM on older Red Hat releases; on modern systems like RHEL 10, DNF is the standard package manager. DNF installs, updates, removes, and searches packages — but it relies on repositories to locate those packages.
A dark presentation slide titled "From YUM to DNF" showing a left panel for legacy YUM (used on older RHEL releases) and a right panel for DNF (standard today, the tool to use on RHEL 10). A blue arrow between the panels indicates the migration from YUM to DNF.
What DNF does:
A dark slide titled "What DNF Does and Where It Looks" showing four outlined panels with icons and labels: Install, Update, Remove, and Search. Each panel contains a simple teal icon representing the respective action.
Because RHEL is subscription-based, systems must be registered with Red Hat to access the official Red Hat repositories. If a system is not registered, package operations such as install or update can fail.
A dark-themed infographic slide that says "Register First, Then You Get Access" and highlights "Register the system with Red Hat" inside a rounded box with a key icon. A downward arrow points toward another box labeled "Official Repositories."
A dark-themed infographic titled "Not Registered? Expect Errors" showing a boxed warning "System not registered" with arrows pointing to two panels labeled "Install fails" and "Update fails."
Register your system with subscription-manager and attach an appropriate subscription using your Red Hat account credentials:
Registering is required to access Red Hat’s official repositories. Without it, DNF cannot retrieve packages from those repositories.

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Repository basics

A repository (repo) is a location that stores RPM packages and metadata. Repositories can be:
  • Official Red Hat repositories (requires subscription/registration).
  • Third-party repositories (e.g., Docker, vendor repos).
  • Internal/private repositories hosted inside your organization.
DNF reads repository definitions from files in /etc/yum.repos.d/ (files ending in .repo) or from files managed by subscription-manager (e.g. /etc/yum.repos.d/redhat.repo).

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Common repository commands

  • List enabled repositories:
  • List enabled repositories with detailed info including base URL:
  • List all repositories, including disabled ones:
  • Enable/disable repositories with subscription-manager:
  • Toggle repositories without editing files using dnf config-manager (provided by dnf-plugins-core):

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Understanding .repo files

Repo definitions use a simple INI-style format. Files belong in /etc/yum.repos.d/ and must end with .repo. A repository stanza looks like:
  • [repo-id] — short identifier (required)
  • name — human-friendly name (recommended)
  • baseurl — URL or local path where packages/metadata are stored
  • enabled — 1 (enabled) or 0 (disabled)
  • gpgcheck — 1 to verify package signatures (recommended)
  • gpgkey — URL or file path to the signing key
Use the table below for a quick reference: Example .repo file (Docker CE):
Knowing how .repo files work is useful even if you primarily use subscription-manager or dnf config-manager.

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Demo: create and use a custom repository

The following demo shows how to add a custom repo file, refresh metadata, inspect available packages, and install a package from that repository. Use caution when mixing repositories from different distributions or major releases.
Mixing repositories from a different distribution or a different major release (for example, adding Rocky Linux 9 repositories to a RHEL 10 system) can cause dependency conflicts and break package resolution. Use such cross-distro repositories only for isolated testing. Also, setting gpgcheck=0 disables package signature verification and is insecure for production; prefer gpgcheck=1 with a valid gpgkey.
  1. Create a new repo file:
Add the following contents (example pointing to Rocky Linux 9 BaseOS):
  1. Refresh DNF metadata and cache:
During makecache DNF downloads repository metadata for enabled repositories — you should see the metadata for rocky-baseos if the baseurl is reachable.
  1. Verify the repository is active:
Example truncated output might include:
  1. List available packages from the new repository:
Sample package list (truncated):
  1. Install a package from the repository:
You should see a transaction summary and download progress. Example (truncated):

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Notes on repository versions and priorities

  • Package versions and release tags (e.g., .el9, .el10) will vary depending on repository origin. Mixing repos from different major releases can introduce incompatible packages.
  • Consider repository priorities or modular filtering if you need to control which repo provides a package on systems with many enabled repositories. RHEL provides tooling and best practices to manage this in production.

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Toggling a repository quickly

You can enable or disable repositories without editing files using dnf config-manager:

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Summary

After this lesson you should be able to:
  • Register a system to access Red Hat repositories.
  • List repositories and inspect repository metadata.
  • Enable or disable repositories via subscription-manager or dnf config-manager.
  • Create a .repo file manually and refresh repository metadata.
  • List packages in a specific repository and install packages from it.

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