How to Create YUM on Linux Server for Local Repositories

Create YUM on a Linux server by building a local YUM repository (from an ISO or mirrored packages), generating metadata with createrepo_c, serving it over HTTP/HTTPS, and adding a .repo file on clients that points to your baseurl. This enables fast, controlled, and offline-ready package management across RHEL/CentOS/AlmaLinux/Rocky systems.

In this guide, I’ll show you how to create YUM on Linux server step by step—specifically, how to create a local YUM repository that you can host privately or mirror from upstream sources.

Whether you’re running CentOS 7, AlmaLinux/Rocky 8/9, or RHEL, this tutorial covers offline setups, syncing, GPG security, and real-world maintenance.

What is YUM (and DNF) and Why Build Your Own Repo?

Creating your own YUM repository centralizes packages for speed, control, and compliance—ideal for data centers, air-gapped networks, and consistent DevOps environments.

Prerequisites

• A Linux server (RHEL/CentOS 7 or AlmaLinux/Rocky/RHEL 8/9) with sudo/root access
• Basic networking, firewall, and SELinux familiarity
• For RHEL: active subscription or a valid content source; for community: AlmaLinux/Rocky/CentOS Stream mirrors
• Web server to host the repository (Apache httpd or Nginx)
• Utilities: createrepo_c, and optionally reposync (from yum-utils or dnf-plugins-core)

Quick Decision: Two Ways to Create a YUM Repository

• Offline/local repo from ISO or a directory of RPMs (best for air-gapped or curated package sets)
• Mirrored repo with reposync from upstream sources (best for keeping a local mirror up to date)

Option 1: Create a Local YUM Repository from ISO or RPM Directory

This method builds a repository from packages you already have—like a RHEL/AlmaLinux/Rocky ISO or a custom RPM collection. It’s the fastest way to create YUM on Linux server for offline use.

Step 1: Install Required Tools

# RHEL/CentOS 7
sudo yum install -y createrepo yum-utils httpd

# AlmaLinux/Rocky/RHEL 8/9
sudo dnf install -y createrepo_c dnf-plugins-core httpd

Step 2: Prepare a Repository Directory

sudo mkdir -p /var/www/html/repos/localrepo
sudo chown -R root:root /var/www/html/repos
sudo chmod -R 755 /var/www/html/repos

Step 3: (Optional) Mount an ISO and Copy Packages

If you’re using a distribution ISO (e.g., AlmaLinux-9.x-x86_64-dvd.iso), mount and copy RPMs from the BaseOS/AppStream (or Packages) directories.

sudo mkdir -p /mnt/iso
sudo mount -o loop /path/to/AlmaLinux-9.x-x86_64-dvd.iso /mnt/iso

# Copy BaseOS and AppStream packages (adjust paths per distro)
sudo cp -av /mnt/iso/BaseOS/Packages/*.rpm /var/www/html/repos/localrepo/
sudo cp -av /mnt/iso/AppStream/Packages/*.rpm /var/www/html/repos/localrepo/

Alternatively, copy your curated RPMs into the same directory if you’re building a custom repo.

Step 4: Generate Metadata with createrepo_c

# Initialize repository metadata
sudo createrepo_c /var/www/html/repos/localrepo

# Later, when updating with new RPMs, use --update:
sudo createrepo_c --update /var/www/html/repos/localrepo

Step 5: Serve the Repo over HTTP (Apache)

sudo systemctl enable httpd --now

# If SELinux is enforcing, allow Apache to read the repo directory
sudo chcon -R -t httpd_sys_content_t /var/www/html/repos

# Open firewall if needed
sudo firewall-cmd --add-service=http --permanent
sudo firewall-cmd --reload

Your repository base URL is now:

http://<your-server-ip-or-domain>/repos/localrepo

Step 6: Create a .repo File on Client Machines

sudo tee /etc/yum.repos.d/localrepo.repo > /dev/null <<'EOF'
[localrepo]
name=Local YUM Repository
baseurl=http://<your-server-ip-or-domain>/repos/localrepo
enabled=1
gpgcheck=0
EOF

# Refresh cache and test
sudo yum clean all && sudo yum makecache
sudo yum repolist

# Install a package to verify
sudo yum install -y <package-name>

Set gpgcheck=1 after you sign packages or the repository metadata with a GPG key (covered below).

(Optional) Step 7: Enable GPG Signing for Security

Signing adds trust. Generate or import a GPG key, sign RPMs or metadata, and point clients to your public key.

# Create a GPG key (interactive)
gpg --full-generate-key

# Export public key to serve via HTTP
gpg --export -a "Your Name or Repo Key" | sudo tee /var/www/html/repos/RPM-GPG-KEY-localrepo

# On clients, import and enforce gpgcheck
sudo rpm --import http://<server>/repos/RPM-GPG-KEY-localrepo

# Then set in /etc/yum.repos.d/localrepo.repo
gpgcheck=1
gpgkey=http://<server>/repos/RPM-GPG-KEY-localrepo

Option 2: Mirror an Upstream Repository with reposync

Use reposync to mirror official repositories locally. This reduces external bandwidth and speeds up updates across many servers.

Step 1: Install reposync Utilities

# RHEL/CentOS 7
sudo yum install -y yum-utils httpd

# AlmaLinux/Rocky/RHEL 8/9
sudo dnf install -y dnf-plugins-core httpd

Step 2: Choose Which Repos to Mirror

• AlmaLinux/Rocky 8/9: BaseOS, AppStream, Extras
• RHEL 8/9: BaseOS, AppStream (requires subscription access)
• CentOS 7: base, updates, extras (EOL note: plan migration)

Step 3: Run reposync

Create a directory structure and sync. Examples below show AlmaLinux 9; adjust for your distro and architecture.

BASE=/var/www/html/repos/almalinux9
sudo mkdir -p $BASE/{BaseOS,AppStream}
# Sync packages and metadata
sudo reposync -p $BASE/BaseOS --download-metadata --repo=almalinux-baseos
sudo reposync -p $BASE/AppStream --download-metadata --repo=almalinux-appstream

# If your reposync doesn't add repodata, generate it:
sudo createrepo_c $BASE/BaseOS
sudo createrepo_c $BASE/AppStream

On RHEL, ensure your subscription repos are enabled before syncing. On CentOS 7, use the repo IDs from /etc/yum.repos.d/CentOS-Base.repo.

Step 4: Serve and Expose Your Mirror

sudo systemctl enable httpd --now
sudo chcon -R -t httpd_sys_content_t /var/www/html/repos
sudo firewall-cmd --add-service=http --permanent
sudo firewall-cmd --reload

Create client repo files that point to your mirror:

# AlmaLinux 9 example:
sudo tee /etc/yum.repos.d/alma-local.repo > /dev/null <<'EOF'
[almalinux-BaseOS-local]
name=AlmaLinux 9 BaseOS (Local)
baseurl=http://<server>/repos/almalinux9/BaseOS
enabled=1
gpgcheck=1
gpgkey=https://repo.almalinux.org/almalinux/RPM-GPG-KEY-AlmaLinux-9

[almalinux-AppStream-local]
name=AlmaLinux 9 AppStream (Local)
baseurl=http://<server>/repos/almalinux9/AppStream
enabled=1
gpgcheck=1
gpgkey=https://repo.almalinux.org/almalinux/RPM-GPG-KEY-AlmaLinux-9
EOF

sudo dnf clean all && sudo dnf makecache
sudo dnf repolist

Maintenance: Keep Your YUM Repository Healthy

• Automate syncs: run reposync nightly/weekly via cron or systemd timers
• Prune old packages: use reposync –delete to remove upstream-deleted packages
• Regenerate metadata: createrepo_c –update when adding/removing RPMs
• Monitor storage: NVMe-backed VPS or dedicated servers handle repo mirrors better under load
• Secure access: prefer HTTPS, restrict by IP/VPN for internal repos

# Example cron job (as root) to sync nightly at 2:30 AM
cat <<'CRON' >> /etc/crontab
30 2 * * * root reposync -p /var/www/html/repos/almalinux9/BaseOS --download-metadata --repo=almalinux-baseos --delete
35 2 * * * root reposync -p /var/www/html/repos/almalinux9/AppStream --download-metadata --repo=almalinux-appstream --delete
# Refresh metadata if needed
40 2 * * * root createrepo_c --update /var/www/html/repos/almalinux9/BaseOS
45 2 * * * root createrepo_c --update /var/www/html/repos/almalinux9/AppStream
CRON

Security Best Practices for Private YUM Repos

• Enable gpgcheck=1 and distribute your GPG public key
• Serve over HTTPS with a valid certificate (Let’s Encrypt for internet-facing repos)
• Use basic auth or IP allowlists for internal repositories
• Audit changes: version control your repo .repo files and sync scripts
• Harden Apache/Nginx and keep OS patched via your new repo

YUM vs DNF: Commands You’ll Use

• Install: yum install pkg equals dnf install pkg
• Update cache/list repos: yum makecache, yum repolist equals dnf makecache, dnf repolist
• Clean cache: yum clean all equals dnf clean all
• Mirror: yum-utils reposync (EL7) vs dnf-plugins-core reposync (EL8/9)

On modern systems, the yum command is often a symlink to dnf. All steps here work on both, with package names adjusted per version.

Troubleshooting Common YUM Repository Errors

• Cannot find a valid baseurl: Verify baseurl in .repo, DNS, and firewall; ensure Apache is running and accessible
• repodata/repomd.xml not found: Run createrepo_c in the repo directory or ensure –download-metadata with reposync
• GPG check failed: Import the correct GPG key and confirm gpgkey URL; set gpgcheck=0 temporarily for diagnostics
• 404 on packages: Check SELinux context (httpd_sys_content_t) and directory permissions (755)
• Mismatched architecture: Ensure you’re syncing/serving the correct basearch (x86_64, aarch64)

Real-World Tips from the Hosting Floor

• Split repos by environment (prod/stage/dev) to isolate package versions
• Cache popular packages on edge nodes close to your app servers
• For large estates, mirror only what you need with –repo filters and include/exclude lists
• Document your repo IDs and keep .repo files minimal and consistent via configuration management

Hosting your private YUM repo on a fast NVMe VPS or a dedicated server improves throughput during patch windows. YouStable offers optimized VPS and bare-metal options ideal for mirrors, with bandwidth, snapshots, and DDoS protection that keep your repos reliable under load.

FAQs