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Dnf_yum

Chapter 29: dnf/yum - Red Hat Package Manager Deep Dive

Section titled “Chapter 29: dnf/yum - Red Hat Package Manager Deep Dive”

Mastering Package Management on Red Hat-Based Systems

Section titled “Mastering Package Management on Red Hat-Based Systems”

28.1 Understanding DNF and YUM

Section titled “28.1 Understanding DNF and YUM”

What is DNF?

Section titled “What is DNF?”

DNF (Dandified YUM) is the next-generation package manager for RPM-based distributions. It was introduced in Fedora 18 and became the default in Fedora 22, replacing the older YUM. RHEL 8 and CentOS Stream also use DNF as the default package manager.

                     RPM Package Management Evolution
+------------------------------------------------------------------+
|                                                                   |
|    YUM (Yellowdog Updater Modified)                               |
|    +----------------------------------------------------------+   |
|    |  - Original package manager for RHEL, CentOS, Fedora      |   |
|    |  - Written in Python                                      |   |
|    |  - Deprecated in favor of DNF                            |   |
|    |  - Still available in RHEL 7                            |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    DNF (Dandified YUM)                                           |
|    +----------------------------------------------------------+   |
|    |  - Drop-in replacement for YUM                           |   |
|    |  - Written in C (performance improvement)                 |   |
|    |  - Better dependency resolution                           |   |
|    |  - Faster and more efficient                             |   |
|    |  - Default in RHEL 8+, Fedora 22+                       |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Compatibility:                                                 |
|    +----------------------------------------------------------+   |
|    |  dnf provides yumbase for backward compatibility           |   |
|    |  Most yum commands work with dnf                          |   |
|    +----------------------------------------------------------+   |
|                                                                   |
+------------------------------------------------------------------+

Architecture

Section titled “Architecture”
                     DNF Architecture
+------------------------------------------------------------------+
|                                                                   |
|                        User Space                                  |
|    +-------------------------------------------------------------+ |
|    |                     dnf Command                              | |
|    |  (High-level interface for end users)                        | |
|    +-------------------------------------------------------------+ |
|                              |                                      |
|                              v                                      |
|    +-------------------------------------------------------------+ |
|    |                    libdnf Library                            | |
|    |  (Shared library for package management)                     | |
|    +-------------------------------------------------------------+ |
|                              |                                      |
|                              v                                      |
|    +-------------------------------------------------------------+ |
|    |                    hawkey/libsolv                           | |
|    |  (Dependency resolver - written in C)                        | |
|    +-------------------------------------------------------------+ |
|                              |                                      |
|                              v                                      |
|    +-------------------------------------------------------------+ |
|    |                    RPM Database                              | |
|    |  (/var/lib/rpm - package database)                          | |
|    +-------------------------------------------------------------+ |
|                                                                   |
|                        Kernel Space                                |
|    +-------------------------------------------------------------+ |
|    |                  File System Operations                      | |
|    |  (/var/cache/dnf - package cache)                          | |
|    |  (/var/lib/rpm - RPM database)                             | |
|    +-------------------------------------------------------------+ |
|                                                                   |
+------------------------------------------------------------------+

28.2 YUM/DNF Commands Comparison

Section titled “28.2 YUM/DNF Commands Comparison”

Command Mapping

Section titled “Command Mapping”
                     YUM to DNF Command Mapping
+------------------------------------------------------------------+
|                                                                   |
|    YUM Command              | DNF Command           | Notes         |
|    ------------------------|----------------------|---------------|
|    yum install             | dnf install          | Same         |
|    yum update              | dnf upgrade          | Preferred    |
|    yum remove              | dnf remove           | Same         |
|    yum search              | dnf search           | Same         |
|    yum info                | dnf info             | Same         |
|    yum list                | dnf list             | Same         |
|    yum repolist            | dnf repolist         | Same         |
|    yum group list          | dnf group list       | Same         |
|    yum history             | dnf history          | Enhanced     |
|    yum localinstall        | dnf install          | No longer    |
|    yum deplist             | dnf repoquery       | Replaced     |
|    yum provides            | dnf provides        | Same         |
|    yum check-update        | dnf check-update    | Same         |
|    yum clean all           | dnf clean all       | Same         |
|    yum makecache           | dnf makecache       | Same         |
|                                                                   |
|    YUM-Specific            | DNF Replacement      |               |
|    ------------------------|----------------------|---------------|
|    yum-complete-transaction| dnf-remove-leaves   | Removed      |
|    yum-debug-dump          | -                   | Removed      |
|    yum-debug-restore       | -                   | Removed      |
|    yum-groups-manager      | -                   | Removed      |
|                                                                   |
+------------------------------------------------------------------+

28.3 Repository Management

Section titled “28.3 Repository Management”

Repository Types

Section titled “Repository Types”
                     RHEL/CentOS Repository Types
+------------------------------------------------------------------+
|                                                                   |
|    Base Repository                                                |
|    +----------------------------------------------------------+   |
|    |  - Core packages from RHEL/CentOS                        |   |
|    |  - Stability and security patches                        |   |
|    |  - Examples: coreutils, systemd, httpd                 |   |
|    |  - BaseOS and AppStream in RHEL 8+                     |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Updates Repository                                            |
|    +----------------------------------------------------------+   |
|    |  - Latest bug fixes and security patches               |   |
|    |  - Automatically enabled                                |   |
|    |  - Checked during 'dnf update'                         |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    AppStream Repository (RHEL 8+)                                 |
|    +----------------------------------------------------------+   |
|    |  - Additional applications and runtimes                 |   |
|    |  - Multiple versions of packages                        |   |
|    |  - Includes modules and streams                        |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Extra Packages for Enterprise Linux (EPEL)                      |
|    +----------------------------------------------------------+   |
|    |  - Extra packages from Fedora                           |   |
|    |  - Not officially supported                             |   |
|    |  - Community-maintained                                |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Third-Party Repositories                                       |
|    +----------------------------------------------------------+   |
|    |  - Docker, Nginx, PostgreSQL, MariaDB, etc.            |   |
|    |  - Vendor-provided packages                            |   |
|    |  - Usually requires GPG key import                     |   |
|    +----------------------------------------------------------+   |
|                                                                   |
+------------------------------------------------------------------+

Repository Configuration Files

Section titled “Repository Configuration Files”
Terminal window
# /etc/yum.repos.d/ directory structure


# Example: nginx.repo
[nginx-stable]
name=nginx stable repo
baseurl=http://nginx.org/packages/centos/$releasever/$basearch/
gpgcheck=1
enabled=1
gpgkey=https://nginx.org/keys/nginx_signing.key
module_hotfixes=true
priority=1


# Example: docker-ce.repo
[docker-ce-stable]
name=Docker CE Stable - $basearch
baseurl=https://download.docker.com/linux/centos/$releasever/$basearch/stable
enabled=1
gpgcheck=1
gpgkey=https://download.docker.com/linux/centos/gpg


# Example: epel.repo (from epel-release package)
[epel]
name=Extra Packages for Enterprise Linux $releasever - $basearch
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL-$releasever

Managing Repositories

Section titled “Managing Repositories”
Terminal window
# List all repositories
dnf repolist
dnf repolist all  # including disabled


# List specific repository
dnf repolist enabled
dnf repolist disabled


# Enable repository
sudo dnf config-manager --enable nginx-stable
sudo dnf config-manager --set-enabled nginx-stable


# Disable repository
sudo dnf config-manager --disable nginx-stable
sudo dnf config-manager --set-disabled nginx-stable


# Add new repository
sudo dnf config-manager --add-repo https://example.com/repo.repo


# Set repository options
sudo dnf config-manager --save \
    --setopt=nginx-stable.priority=1 \
    --setopt=nginx-stable.skip_if_unavailable=true


# View repository configuration
dnf repoquery --repoid=nginx-stable


# Clean repository cache
dnf clean all
dnf clean metadata


# Make cache
dnf makecache
dnf makecache timer  # download metadata if older than timer

28.4 Module Streams (AppStream)

Section titled “28.4 Module Streams (AppStream)”

Understanding Modules

Section titled “Understanding Modules”

RHEL 8+ introduced the concept of modules from the AppStream repository, allowing multiple versions of software to be available simultaneously.

                     AppStream Module Streams
+------------------------------------------------------------------+
|                                                                   |
|    Concept:                                                        |
|    +----------------------------------------------------------+   |
|    |  Modules = Collection of RPM packages                     |   |
|    |  Streams = Different versions of a module                |   |
|    |  Profiles = Purpose-specific package sets                |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Example: Node.js Module                                        |
|    +----------------------------------------------------------+   |
|    |  nodejs:10       - Node.js 10 (end-of-life)            |   |
|    |  nodejs:12       - Node.js 12 (deprecated)             |   |
|    |  nodejs:14       - Node.js 14 (supported)              |   |
|    |  nodejs:16       - Node.js 16 (supported)              |   |
|    |  nodejs:18       - Node.js 18 (default)                |   |
|    |                                                            |   |
|    |  Profiles for nodejs:18:                                 |   |
|    |    - common (default) - core runtime                    |   |
|    |    - development - includes npm, node-gyp               |   |
|    |    - minimal    - minimal installation                  |   |
|    |    - s2i        - source-to-image support             |   |
|    +----------------------------------------------------------+   |
|                                                                   |
+------------------------------------------------------------------+

Module Commands

Section titled “Module Commands”
Terminal window
# List all available modules
dnf module list


# List specific module
dnf module list nodejs


# Show module information
dnf module info nodejs:18


# Enable module stream
sudo dnf module enable nodejs:18


# Disable module stream
sudo dnf module disable nodejs


# Reset module stream
sudo dnf module reset nodejs


# Install from module
sudo dnf module install nodejs:18
sudo dnf module install nodejs:18/development


# Install default stream
sudo dnf module install nodejs


# Remove module package
sudo dnf module remove nodejs

28.5 Package Groups

Section titled “28.5 Package Groups”

Group Types

Section titled “Group Types”
                     Package Groups in RHEL
+------------------------------------------------------------------+
|                                                                   |
|    Environment Groups                                             |
|    +----------------------------------------------------------+   |
|    |  - Define entire system environment                       |   |
|    |  - Examples: "Server with GUI", "Minimal Install"       |   |
|    |  - Used during installation                             |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Task Groups                                                    |
|    +----------------------------------------------------------+   |
|    |  - Group packages by functionality                       |   |
|    |  - Examples: "Development Tools", "System Tools"        |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Language Groups                                                |
|    +----------------------------------------------------------+   |
|    |  - Localization packages                                  |   |
|    |  - Examples: "Spanish Support", "Japanese Support"     |   |
|    +----------------------------------------------------------+   |
|                                                                   |
+------------------------------------------------------------------+

Group Commands

Section titled “Group Commands”
Terminal window
# List all groups
dnf group list


# List hidden groups
dnf group list --hidden


# List available groups with IDs
dnf group list --ids


# View group information
dnf group info "Development Tools"


# Install group
sudo dnf group install "Development Tools"
sudo dnf group install @development  # using ID


# Install with optional packages
sudo dnf group install "Development Tools" --with-optional


# Remove group
sudo dnf group remove "Development Tools"


# List packages in group
dnf group packages "Development Tools"

28.6 Package Dependencies

Section titled “28.6 Package Dependencies”

Dependency Resolution

Section titled “Dependency Resolution”
                     DNF Dependency Resolution
+------------------------------------------------------------------+
|                                                                   |
|    hawkey/libsolv Algorithm:                                       |
|    +----------------------------------------------------------+   |
|    |  1. Collect all dependencies                              |   |
|    |  2. Build dependency graph                                |   |
|    |  3. Apply policies (install, update, remove)             |   |
|    |  4. Resolve conflicts                                    |   |
|    |  5. Create transaction                                   |   |
|    |  6. Order for installation/removal                      |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Resolution Policies:                                            |
|    +----------------------------------------------------------+   |
|    |  best      - Use highest version (default)              |   |
|    |  all       - Resolve for all                             |   |
|    |  install   - Only for installation                      |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Conflict Resolution:                                            |
|    +----------------------------------------------------------+   |
|    |  DNF automatically resolves most conflicts               |   |
|    |  For manual resolution, use 'dnf remove' first          |   |
|    |  Use '--best' to force latest versions                 |   |
|    +----------------------------------------------------------+   |
|                                                                   |
+------------------------------------------------------------------+

Dependency Commands

Section titled “Dependency Commands”
Terminal window
# Find package providing file
dnf provides /etc/nginx/nginx.conf
dnf provides nginx


# List package dependencies
dnf repoquery --requires nginx


# List packages that depend on package
dnf repoquery --alleviates --requires nginx
dnf rdepends nginx


# Check dependencies before install (dry run)
dnf repoquery --requires --resolve nginx
dnf repoquery --alldeps nginx


# Check for broken dependencies
dnf check


# List package dependencies recursively
dnf repoquery --requires --resolve nginx

28.7 RPM Commands

Section titled “28.7 RPM Commands”

Direct RPM Management

Section titled “Direct RPM Management”
Terminal window
# Query installed packages
rpm -qa                              # all
rpm -qa | grep nginx                 # specific
rpm -qi nginx                        # info


# Query package files
rpm -ql nginx                        # list files
rpm -qc nginx                        # config files
rpm -qd nginx                        # doc files


# Query package dependencies
rpm -qR nginx                       # requires
rpm -q --whatrequires nginx         # required by


# Verify package
rpm -V nginx                         # verify
rpm -Va                              # verify all


# Install RPM (doesn't resolve dependencies)
sudo rpm -ivh package.rpm


# Upgrade RPM (removes old version)
sudo rpm -Uvh package.rpm


# Freshen RPM (only if older exists)
sudo rpm -Fvh package.rpm


# Uninstall
sudo rpm -e package-name


# Query database
rpm -q --last                       # by install time
rpm -q --changelog nginx            # changelog
rpm -qf /path/to/file               # what owns file

28.8 Transaction History

Section titled “28.8 Transaction History”

Using History

Section titled “Using History”
Terminal window
# List all transactions
dnf history
dnf history list


# Show specific transaction
dnf history info 15
dnf history info last


# Undo transaction (revert changes)
sudo dnf history undo 15
sudo dnf history undo last


# Rollback to state before transaction
sudo dnf history rollback 15


# Repeat last transaction
sudo dnf history repeat


# New in DNF: User packages and groups
dnf history userinstalled


# History statistics
dnf history stats

28.9 Plugin Management

Section titled “28.9 Plugin Management”

DNF Plugins

Section titled “DNF Plugins”
Terminal window
# Install DNF plugins
sudo dnf install dnf-plugins-core
sudo dnf install dnf-plugins-extras


# Common plugins:
# dnf-plugins-core: (included by default)
#   - config-manager
#   - copr
#   - debug
#   - download
#   - groups-manager
#   - needs-restarting
#   - plugin-pkg
#   - repoclosure
#   - repodiff
#   - repograph
#   - repomanage
#   - reposync


# Enable/disable plugin
dnf --disablerepo=* install package
dnf -x package install other-package


# Check which plugins are running
dnf repolist -v | grep "From repo"

28.10 DNF Configuration

Section titled “28.10 DNF Configuration”

Configuration Files

Section titled “Configuration Files”
                     DNF Configuration Hierarchy
+------------------------------------------------------------------+
|                                                                   |
|    /etc/dnf/dnf.conf                                             |
|    +----------------------------------------------------------+   |
|    |  Main configuration file                                  |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    /etc/dnf/plugins/                                             |
|    +----------------------------------------------------------+   |
|    |  Plugin-specific configuration                           |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    /etc/yum.repos.d/*.repo                                       |
|    +----------------------------------------------------------+   |
|    |  Repository configuration                               |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    ~/.config/dnf/dnf.conf                                        |
|    +----------------------------------------------------------+   |
|    |  User-specific overrides                                |   |
|    +----------------------------------------------------------+   |
|                                                                   |
+------------------------------------------------------------------+

Common Configuration Options

Section titled “Common Configuration Options”
/etc/dnf/dnf.conf
[main]
# Base settings
gpgcheck=1
installonly_limit=3
clean_requirements_on_remove=True
best=True
skip_if_unavailable=False


# Performance
fastestmirror=True
max_parellel_downloads=10
timeout=30


# Updates
autocheck=True
update_installed=True


# Cleaning
clean_requirements_on_remove=True
remove_leaves=True


# Notifications
notify=False


# Logging
logdir=/var/log/dnf
errorlevel=0
debuglevel=2


# Exclude packages
exclude=kernel*,centos*


# Include packages (for security policies)
# includepkgs=package1,package2

28.11 Automatic Updates

Section titled “28.11 Automatic Updates”

dnf-automatic

Section titled “dnf-automatic”
/etc/dnf/automatic.conf
# Install
sudo dnf install dnf-automatic


[commands]
# upgrade_type = default (all) or security
upgrade_type = security
random_sleep = 60
# download_transactions = daemon/systemd
download_transactions = systemd


[emitters]
# emit_via = email/stdio/none
emit_via = email
email_from = dnf@example.com
email_to = admin@example.com
email_host = localhost


[email]
# SMTP settings if needed


[base]
# base settings from dnf.conf also apply


# Enable and start timer
sudo systemctl enable --now dnf-automatic.timer
sudo systemctl enable --now dnf-automatic.service


# Check status
systemctl status dnf-automatic.timer

28.12 Troubleshooting

Section titled “28.12 Troubleshooting”

Common Issues

Section titled “Common Issues”
                     DNF Troubleshooting Guide
+------------------------------------------------------------------+
|                                                                   |
|    Issue: Repository metadata expired                              |
|    +----------------------------------------------------------+   |
|    |  Solution: dnf clean metadata && dnf makecache         |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Issue: Package conflicts                                        |
|    +----------------------------------------------------------+   |
|    |  Solution: dnf remove conflicting && dnf install       |   |
|    |           Or: dnf upgrade --all                        |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Issue: Missing dependencies                                     |
|    +----------------------------------------------------------+   |
|    |  Solution: dnf repoquery --requires --resolve package  |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Issue: GPG key errors                                          |
|    +----------------------------------------------------------+   |
|    |  Solution: rpm --import /path/to/gpg-key               |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Issue: Held back packages                                       |
|    +----------------------------------------------------------+   |
|    |  Solution: dnf upgrade --best                           |   |
|    +----------------------------------------------------------+   |
|                                                                   |
|    Issue: "Nothing to do" despite updates                          |
|    +----------------------------------------------------------+   |
|    |  Solution: dnf list updates && dnf upgrade            |   |
|    +----------------------------------------------------------+   |
|                                                                   |
+------------------------------------------------------------------+

Recovery Commands

Section titled “Recovery Commands”
Terminal window
# Clean all caches
sudo dnf clean all
sudo rm -rf /var/cache/dnf


# Rebuild database
sudo rpm --rebuilddb


# Check broken dependencies
sudo dnf check


# Remove leaves (unused dependencies)
sudo dnf remove-leaves


# List unneeded dependencies
dnf autoremove


# Fix missing dependencies
sudo dnf install --allowerasing package


# Verify package
rpm -V package


# Force reinstall
sudo dnf reinstall package


# Downgrade package
sudo dnf downgrade package

28.13 Exam Tips

Section titled “28.13 Exam Tips”

Important

  1. DNF vs YUM: DNF is modern replacement, most commands are compatible
  2. AppStream: RHEL 8+ uses modules for multiple package versions
  3. Repository priority: Use priority in repo file to prefer specific repos
  4. Groups: Use dnf group for installing related packages
  5. History: DNF tracks all transactions, can undo/rollback
  6. Modules: Use dnf module for enabling specific versions
  7. Configuration: Main config in /etc/dnf/dnf.conf
  8. Plugins: DNF is extensible via plugins
  9. Automatic updates: Use dnf-automatic for automated patching
  10. Dependencies: Use dnf repoquery to check dependencies

Summary

Section titled “Summary”

In this chapter, you learned:

  • ✅ DNF vs YUM architecture and differences
  • ✅ Repository management and configuration
  • ✅ AppStream modules and streams
  • ✅ Package groups
  • ✅ Dependency resolution with hawkey/libsolv
  • ✅ RPM direct commands
  • ✅ Transaction history (undo/rollback)
  • ✅ DNF plugins and configuration
  • ✅ Automatic updates with dnf-automatic
  • ✅ Troubleshooting common issues

Next Chapter

Section titled “Next Chapter”

Chapter 29: Compiling from Source

Last Updated: February 2026