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Failed to Download Metadata for repo 'appstream' in CentOS ​

Problem ​

When trying to install packages using yum or dnf on CentOS 8, you may encounter the error:

Error: Failed to download metadata for repo 'appstream': Cannot prepare internal mirrorlist: No URLs in mirrorlist

This error occurs because CentOS 8 reached End of Life (EOL) on December 31, 2021. The official mirror URLs have been disabled, and the repositories are no longer available through the standard mirror system.

Solution ​

There are two primary approaches to resolve this issue:

The official solution from CentOS is to migrate from CentOS Linux 8 to CentOS Stream 8, which continues to receive updates.

bash
# Install CentOS GPG keys if needed
wget 'http://mirror.centos.org/centos/8-stream/BaseOS/x86_64/os/Packages/centos-gpg-keys-8-3.el8.noarch.rpm'
sudo rpm -i 'centos-gpg-keys-8-3.el8.noarch.rpm'

# Switch to CentOS Stream repositories
sudo dnf --disablerepo '*' --enablerepo=extras swap centos-linux-repos centos-stream-repos

# Synchronize with the new repositories
sudo dnf distro-sync

After completing these steps, yum and dnf will work normally with the new CentOS Stream 8 repositories.

TIP

CentOS Stream is a rolling-release distribution that sits between Fedora and RHEL, providing a more stable platform than Fedora while offering newer packages than RHEL.

Option 2: Use Archived Repositories (Temporary Fix) ​

If you cannot migrate to CentOS Stream, you can temporarily point your system to the archived CentOS 8 repositories:

bash
# Navigate to the repos directory
cd /etc/yum.repos.d/

# Comment out mirrorlist entries
sudo sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-*

# Enable vault.centos.org as the baseurl
sudo sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*

# Update your system
sudo yum update -y

WARNING

This solution provides access to archived packages but will not receive security updates or bug fixes. It should only be used as a temporary measure before migrating to a supported distribution.

Dockerfile Solution ​

If you're encountering this error in a Docker build, modify your Dockerfile:

dockerfile
FROM centos:8

# Fix repository configuration
RUN sed -i 's/mirrorlist/#mirrorlist/g' /etc/yum.repos.d/CentOS-* && \
    sed -i 's|#baseurl=http://mirror.centos.org|baseurl=http://vault.centos.org|g' /etc/yum.repos.d/CentOS-*

# Install your packages
RUN yum -y install java

# Continue with your build steps

For CentOS Stream 9 Users ​

If you're using CentOS Stream 9 and experiencing similar issues, check your repository configuration:

bash
# Edit the centos.repo file
sudo vi /etc/yum.repos.d/centos.repo

Ensure that any repositories causing errors have enabled=0 instead of enabled=1.

Best Practices ​

  1. Migrate to a supported distribution - Consider upgrading to CentOS Stream, AlmaLinux, Rocky Linux, or another RHEL-compatible distribution
  2. Keep systems updated - Regular updates ensure security patches are applied
  3. Plan for EOL transitions - Monitor end-of-life dates for your distributions and plan migrations accordingly

DANGER

Continuing to use CentOS 8 without security updates exposes your system to vulnerabilities. Migrate to a supported distribution as soon as possible.

Conclusion ​

The "Failed to download metadata for repo 'appstream'" error occurs because CentOS 8 has reached end-of-life. The recommended solution is to migrate to CentOS Stream 8 using the official migration path. While temporary fixes using archived repositories work, they don't provide ongoing security updates and should only be used as a stopgap measure.