Linux — Package Management with DNF

Overview

Software on Red Hat Enterprise Linux is distributed as RPM packages — self-contained archives that bundle compiled binaries, configuration files, documentation, and metadata describing the package name, version, dependencies, and every file it owns. The RPM format is the foundation; the tooling built on top handles dependency resolution and repository management automatically.

Two layers of tooling exist on RHEL:

RPM (rpm command) — the low-level package manager that installs, removes, queries, and verifies individual .rpm files directly. It does not resolve dependencies: if a package requires a library that is not installed, RPM reports an error and stops. RPM is primarily used for querying the package database and verifying installed file integrity.
DNF (Dandified YUM, dnf command) — the high-level package manager that reads from configured repositories, resolves the complete dependency graph automatically, and calls RPM to execute the changes. For virtually all day-to-day administration, DNF is the correct tool. The yum command is a compatibility symlink to dnf on RHEL 9.

A third prerequisite for accessing Red Hat’s official repositories is a subscription, managed by subscription-manager and the Red Hat Subscription Manager (RHSM) service.

RPM Package Format

Every RPM filename follows a predictable naming convention:

name-version-release.architecture.rpm

Example: httpd-2.4.51-7.el9.x86_64.rpm

Field	Example	Meaning
name	`httpd`	Package name
version	`2.4.51`	Upstream software version
release	`7.el9`	RPM build number; `.el9` indicates built for RHEL 9
architecture	`x86_64`	Target CPU architecture

Common architecture values:

x86_64 — 64-bit Intel and AMD (most servers)
aarch64 — 64-bit ARM
noarch — architecture-independent (shell scripts, pure-Python, documentation)

The RPM database at /var/lib/rpm tracks all installed packages, their file lists, and their checksums. Every rpm query operation reads from this database.

rpm Command Reference

# Query installed packages
rpm -q packagename              # Is this package installed? Shows version if yes.
rpm -qa                         # List all installed packages (pipe to grep for search)
rpm -qi packagename             # Detailed info: description, install date, size, vendor
rpm -ql packagename             # List all files installed by this package
rpm -qf /path/to/file           # Which package owns this file?
rpm -qR packagename             # Packages and libraries this package requires
rpm -q --changelog packagename  # Show the package changelog

# Query a local .rpm file (not yet installed)
rpm -qip package.rpm            # Info about a downloaded RPM file
rpm -qlp package.rpm            # Files that a downloaded RPM would install

# Verify package integrity
rpm -V packagename              # Compare installed files against RPM database checksums
rpm -Va                         # Verify all installed packages

# Install and remove (use dnf for these instead when possible)
rpm -ivh package.rpm            # Install local RPM (verbose, progress bar)
rpm -Uvh package.rpm            # Upgrade or install
rpm -e packagename              # Remove (erase) a package

The rpm -qf command is invaluable for troubleshooting: given any file on the system, it immediately identifies which package installed it, allowing you to investigate, reinstall, or remove the owning package.

The rpm -V output lines use single-character codes to indicate what changed: S for file size, M for mode/permissions, 5 for MD5 checksum, T for modification timestamp. A package whose files have not been tampered with produces no output.

DNF Package Manager

DNF is the default package manager for RHEL 9, Fedora, and CentOS Stream. The yum command on RHEL 9 is a compatibility alias that maps to dnf-3.

Information and Search Commands

dnf list                                # List all installed and available packages
dnf list installed                      # Installed packages only
dnf list available                      # Packages available in enabled repositories
dnf list kernel                         # Show all installed kernel versions
dnf search keyword                      # Search package name and summary fields
dnf search all keyword                  # Search all metadata fields (slower but thorough)
dnf info packagename                    # Detailed information including repo, size, description
dnf provides /usr/bin/htpasswd          # Which package provides this file?
dnf provides "command"                  # Which package provides this command name?

dnf provides is the DNF equivalent of rpm -qf for packages not yet installed. When a build or script fails because a binary or header file is missing, dnf provides /path/to/file identifies the package to install.

Install, Update, and Remove

dnf install packagename                 # Install package and all dependencies
dnf install /path/to/package.rpm        # Install a local RPM file with dependency resolution
dnf remove packagename                  # Remove package and any packages depending solely on it
dnf update                              # Update all installed packages to latest versions
dnf update packagename                  # Update a specific package only
dnf downgrade packagename               # Install the previous version of a package
dnf reinstall packagename               # Reinstall from repository (useful after accidental deletion)

Groups

Package groups bundle related packages for a purpose:

dnf group list                          # List all available package groups
dnf group list hidden                   # Include hidden groups
dnf group info "Development Tools"      # Show packages in a group
dnf group install "Development Tools"   # Install all packages in the group
dnf group remove "Development Tools"    # Remove all packages from a group

Transaction History and Rollback

One of DNF’s most powerful features is its complete transaction history and the ability to undo any past transaction:

dnf history                             # List all transactions with IDs, dates, and summaries
dnf history info N                      # Detailed information about transaction N
dnf history undo N                      # Reverse transaction N (uninstall what was installed)
dnf history redo N                      # Repeat transaction N

Transaction history is stored in /var/lib/dnf/ and logs to /var/log/dnf.rpm.log. This log records every package installation and removal with timestamps, making it a valuable audit trail.

Cleanup

dnf clean all                           # Remove all cached package metadata and downloads
dnf autoremove                          # Remove packages installed as dependencies that are no longer needed

Repository Configuration

DNF reads from repositories defined in .repo files in /etc/yum.repos.d/. Each file can define one or more repositories in INI format:

[repo-id]
name=Descriptive Repository Name
baseurl=https://mirror.example.com/repo/
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-example

Key fields:

enabled=1 / enabled=0 — active or inactive without deleting the file
gpgcheck=1 — verify package signatures against the GPG key (always recommended)
baseurl — URL or local path; mirrorlist= is an alternative pointing to a list of mirrors

dnf repolist                              # List all enabled repositories
dnf repolist all                          # All repositories including disabled ones
dnf config-manager --add-repo URL         # Add a new .repo file from a URL
dnf config-manager --enable repo-id       # Enable a disabled repository
dnf config-manager --disable repo-id      # Disable an enabled repository

# Temporary overrides (for a single dnf command only)
dnf install --enablerepo=repo-id package  # Enable a repo just for this operation
dnf install --disablerepo=repo-id package # Disable a repo just for this operation

Always import the GPG key for any new repository before installing packages:

rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-example

DNF Module Streams and Application Streams

RHEL 9 ships with two primary content repositories:

BaseOS — core OS content as individual RPM packages, with the full RHEL 9 lifecycle
AppStream — applications, runtimes, and development tools, with their own individual lifecycles

AppStream can deliver software in two forms: traditional RPMs and modules. A module groups related packages for a specific version of an application stack. Multiple versions of the same software are available as separate streams (e.g., nodejs:18 and nodejs:20). Only one stream per module may be active on a system at a time.

Module Commands

dnf module list                                # All available modules and their streams
dnf module list module-name                    # Streams for a specific module
dnf module info module-name                    # Detailed module information
dnf module info module-name:stream             # Info about a specific stream
dnf module info --profile module-name:stream   # Package sets for each profile

Enabling and Installing a Module

dnf module enable nodejs:20                    # Enable the Node.js 20 stream
dnf module install nodejs                      # Install packages from the enabled stream
dnf module install nodejs:20/development       # Install a specific profile

Profiles define which subset of module packages to install. Common profiles: default, minimal, server, client, development.

Switching or Resetting a Module Stream

To switch from one stream to another:

dnf module reset nodejs                        # Reset to unset state
dnf module enable nodejs:18                    # Enable the new stream
dnf distro-sync                                # Sync installed packages to the new stream

Or combined:

dnf module switch-to nodejs:18                 # Switch stream in one command

Red Hat Subscription Manager

RHEL systems require a subscription to access the Red Hat Content Delivery Network (CDN) and receive official updates. subscription-manager handles registration, subscription attachment, and repository management.

subscription-manager register                           # Register (prompts for username/password)
subscription-manager register --username USER --password PASS  # Non-interactive
subscription-manager register --auto-attach             # Register and attach best subscription

subscription-manager list --available                   # Show available subscriptions for this account
subscription-manager attach --pool=POOL_ID              # Attach a specific subscription by pool ID
subscription-manager attach --auto                      # Attach the best matching subscription automatically

subscription-manager list --consumed                    # Show currently attached subscriptions
subscription-manager status                             # Overall subscription compliance status

subscription-manager repos --list                       # List all available repositories
subscription-manager repos --enable=repo-id             # Enable a specific repository
subscription-manager repos --disable=repo-id            # Disable a repository

subscription-manager unregister                         # Remove system from subscription service

When a system is registered and a subscription is attached, RHSM automatically creates /etc/yum.repos.d/redhat.repo with the CDN repository URLs and certificates. DNF then uses these repositories without any additional configuration.

Simple Content Access (SCA) simplifies subscription management. With SCA enabled on the Customer Portal or Red Hat Satellite, every registered system can access all repositories from all subscriptions in the organization — no per-system subscription attachment is required. This removes the need for subscription-manager attach in most enterprise environments.

Summary

RPM is the package format and low-level management tool: use rpm -q to query installed packages, rpm -qf to find which package owns a file, and rpm -V to verify file integrity against the RPM database. DNF is the high-level package manager: it resolves dependencies from configured repositories, tracks a complete undoable transaction history, manages module streams for parallel software versions, and handles cleanup of orphaned dependencies. Repository definitions live in /etc/yum.repos.d/ as .repo files. Red Hat systems must be registered with subscription-manager to access the CDN; Simple Content Access eliminates per-system subscription attachment in enterprise environments. AppStream module streams allow multiple versions of the same software (Node.js, Python, Ruby) to be available simultaneously, with only one stream active per system.