6.1 Configure Access to RPM Repositories

6.1 Configure Access to RPM Repositories

Quick Answer: On RHEL 10, define RPM package sources in /etc/yum.repos.d/*.repo (not hand-stacked only in memory). Each repo needs a unique [id], name=, and baseurl= or metalink=/mirrorlist=, plus enabled= and GPG settings. Confirm with dnf repolist and dnf makecache. Configs on disk persist after reboot—required for EX200 credit.

Why repository access is its own exam skill

The official EX200 study points split Manage software into repository access and package install/remove for both RPM and Flatpak. Graders do not care that you memorized dnf install if the system has no usable repo. Typical tasks:

• Add a custom or local repository (directory tree with repodata/)
• Point DNF at an HTTP/HTTPS mirror or training server
• Enable/disable an existing repo
• Fix a broken .repo so packages install again

If the repo is wrong, every later software task fails. Treat this section as the foundation for Section 6.2.

DNF vs yum naming (RHEL 10)

RHEL uses DNF as the package manager stack. The classic yum command remains a familiar front end on many systems (often a compatibility path to DNF). Prefer dnf in modern documentation and on the exam unless a task literally says yum.

Important paths still use the historical yum directory name:

Red Hat’s guidance: define repositories in .repo files under /etc/yum.repos.d/, not by stuffing long-lived repo stanzas only into dnf.conf. Keep dnf.conf for global policy; keep repos modular and easy to enable/disable.

Anatomy of a .repo file

Files must end in .repo or DNF ignores them. One file may contain multiple repository sections.

[exam-appstream]
name=Exam AppStream mirror
baseurl=https://repo.example.com/rhel10/AppStream/x86_64/os/
enabled=1
gpgcheck=1
gpgkey=file:///etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release

Local file repository (common lab/exam pattern)

If packages and metadata live on disk (ISO mount, NFS share, copied tree):

[local-baseos]
name=Local BaseOS
baseurl=file:///mnt/iso/BaseOS
enabled=1
gpgcheck=0

Notes:

• file:// URLs need three slashes for absolute paths: file:///mnt/iso/BaseOS.
• The path must be the repository root that contains repodata/ (or the correct relative structure for that product tree).
• Training labs sometimes set gpgcheck=0 for unsigned local trees. Prefer gpgcheck=1 with a proper gpgkey when keys are provided—match the task.

HTTP/HTTPS remote repository

[training-extra]
name=Training Extra Packages
baseurl=http://materials.example.lab/rhel10/extra/
enabled=1
gpgcheck=1
gpgkey=http://materials.example.lab/RPM-GPG-KEY-training

On a real RHEL system attached to Red Hat CDN, BaseOS/AppStream repos are usually provisioned via subscription-manager content and vendor .repo files. Exam environments may preconfigure CDN access or give you a local/training URL instead—always follow the task wording.

Creating and editing repository definitions

Manual file creation

sudo vim /etc/yum.repos.d/exam-local.repo
# or
sudo tee /etc/yum.repos.d/exam-local.repo <<'EOF'
[exam-local]
name=Exam Local Repo
baseurl=file:///var/www/html/repo
enabled=1
gpgcheck=0
EOF

Permissions: world-readable config is normal; root must own the file. Wrong ownership is rarely the issue—typos in baseurl and missing repodata are.

dnf config-manager (when available)

Many RHEL systems provide dnf config-manager (from dnf-plugins-core) to add or toggle repos without hand-editing:

# Add a repo from a URL (creates a .repo file; often enabled by default)
sudo dnf config-manager --add-repo=https://example.com/my.repo
# or
sudo dnf config-manager --add-repo=http://server.lab/rhel10/

# Enable / disable by repo id
sudo dnf config-manager --set-enabled exam-local
sudo dnf config-manager --set-disabled exam-local

If the plugin is missing in a constrained lab, fall back to editing /etc/yum.repos.d/ directly—the exam grades end state, not which editor you used.

Importing a GPG key

sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-redhat-release
# or from a file the task provides
sudo rpm --import /tmp/RPM-GPG-KEY-training

Keys under /etc/pki/rpm-gpg/ are the usual Red Hat locations. After import, gpgkey=file:///etc/pki/rpm-gpg/... in the .repo file can succeed during install.

Verifying repository access

Never assume a .repo file works. Verify:

# List enabled repositories
dnf repolist

# List all (enabled and disabled)
dnf repolist --all

# Verbose detail including URLs
dnf repolist -v

# Refresh metadata (forces contact with baseurl/metalink)
sudo dnf makecache
# or
sudo dnf clean all
sudo dnf makecache

Success looks like your new repo id appearing in dnf repolist and makecache completing without “Error: Failed to download metadata” or 404-style failures.

Useful inspections:

ls /etc/yum.repos.d/
grep -R "^\[" /etc/yum.repos.d/
cat /etc/dnf/dnf.conf
dnf config-manager --dump   # if plugin present; dumps effective config

Troubleshooting map

Temporary enable/disable without editing files

For a single transaction:

sudo dnf install --enablerepo=exam-local httpd
sudo dnf install --disablerepo="*" --enablerepo=exam-local somepkg

Exam persistence note: --enablerepo on one command does not permanently enable the repo. If the task says “configure the system to use this repository,” edit the .repo (enabled=1) or use config-manager --set-enabled. Runtime-only flags vanish after the shell session—and after reboot the permanent file state is what matters.

Red Hat content layout (conceptual)

Production RHEL 10 systems commonly expose at least:

• BaseOS — core OS packages
• AppStream — user-space applications, runtimes, databases, etc.

You do not need to memorize every RHSM product name for EX200, but you must recognize that multiple repos may be required for a complete package set. Disabling AppStream while installing a desktop or language stack often causes “No match for argument” failures that look like missing packages but are really disabled sources.

Exam workflow: “Add a repository and prove it”

1. Read the task for URL/path, repo id requirements, GPG expectations, and enable state.
2. Create /etc/yum.repos.d/<descriptive>.repo with correct baseurl/metalink.
3. Import GPG keys if provided.
4. Run dnf repolist and dnf makecache.
5. Optionally search for a known package from that repo (dnf search / dnf list) without installing yet if the task only asks for access.
6. Reboot if you have time (or at least re-open a new session) and confirm /etc/yum.repos.d/ content and dnf repolist still show the repo—file-based config should persist; prove it.

Common traps

1. Writing baseurl=file://mnt/iso (two slashes after file: for absolute path misuse) — use file:///mnt/iso/....
2. Pointing baseurl at the ISO file instead of the mounted directory tree containing repodata.
3. Leaving enabled=0 after creating a perfect file.
4. Assuming dnf.conf alone is enough while forgetting /etc/yum.repos.d/.
5. Using spaces or invalid characters carelessly in repo ids — keep ids simple: letters, numbers, hyphens, underscores.
6. Fixing only the client when the server path 404s — verify the remote path with curl -I when network tools are available.

Relationship to later objectives

Section 6.2 assumes repositories work. Chapter objectives on install/update from CDN, remote repo, or local filesystem reuse these same .repo skills. Flatpak (6.3–6.4) is a parallel application distribution system—it does not replace DNF for system RPMs (kernel, httpd, firewalld, etc.).

Section checkpoint

You should be able to create a correct *.repo file, enable or disable repos permanently, import GPG keys, refresh metadata, list available repositories, and leave a configuration that still works after reboot. That is the EX200 definition of “configure access to RPM repositories.”