[SOLVED] RHEL8/Fedora - yum/dns causes cannot download repodata/repomd.xml for docker-ce

Issue

Question

How to fix the Cannot download repodata/repomd.xml: All mirrors were tried for docker-ce.

Problem

Get the error Cannot download repodata/repomd.xml: All mirrors were tried with yum install docker-ce by following the current (as of 2021DEC13) Docker documentations to setup Docker yum/dnf repositories.

• Install Docker Engine on Fedora
• Install Docker Engine on RHEL

Steps & Error

$ sudo dnf -y install dnf-plugins-core
Last metadata expiration check: 0:43:20 ago on Wed 15 Dec 2021 03:47:53 AM UTC.
Package dnf-plugins-core-4.0.21-3.el8.noarch is already installed.
Dependencies resolved.
Nothing to do.
Complete!

$ sudo dnf config-manager \
>     --add-repo \
>     https://download.docker.com/linux/fedora/docker-ce.repo
Adding repo from: https://download.docker.com/linux/fedora/docker-ce.repo

$ sudo yum update
Docker CE Stable - x86_64                                                                                                                                                                                             357  B/s | 383  B     00:01    
Errors during downloading metadata for repository 'docker-ce-stable':
  - Status code: 404 for https://download.docker.com/linux/fedora/8/x86_64/stable/repodata/repomd.xml (IP: 13.224.175.42)
Error: Failed to download metadata for repo 'docker-ce-stable': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried

Environment

Reproduced with 8.4 and 8.5. However, other Fedora/RHEL/CentOS would have the same issue.

$ cat /etc/os-release
NAME="Red Hat Enterprise Linux"
VERSION="8.5 (Ootpa)"

Solution

Cause

The commands specified in the Docker documentations generates incorrect repository configurations.

As per Changes to dockerproject.org APT and YUM repositories, the repository for docker is now moved to download.docker.com. The document links to the Docker documentations such as Install Docker Engine on Fedora.

What do I need to do?

If you are currently using the APT or YUM repositories from dockerproject.org or dockerproject.com, please update to use the repositories at download.docker.com.

You can find instructions for CentOS, Debian, Fedora and Ubuntu in the documentation.

You follow the instruction:

$ sudo dnf config-manager \
    --add-repo \
    https://download.docker.com/linux/fedora/docker-ce.repo

The command creates /etc/yum.repos.d/docker-ce.repo which has wrong URL.

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

As explained in Unable to install docker on rhel 8 linux, it should have been:

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

Not sure who should fix this. Please advise who is in charge.

Solution

Use the command below for RHEL/Fedora instead of the one specified in the Docker documentation.

sudo dnf config-manager \
--add-repo=https://download.docker.com/linux/centos/docker-ce.repo

If the incorrect configuration has been already created.

sed -i -e 's/baseurl=https:\/\/download\.docker\.com\/linux\/\(fedora\|rhel\)\/$releasever/baseurl\=https:\/\/download.docker.com\/linux\/centos\/$releasever/g' /etc/yum.repos.d/docker-ce.repo

---

Note

• Supported platforms

• Install Docker Engine on RHEL

We currently only provide packages for RHEL on s390x (IBM Z). Other architectures are not yet supported for RHEL, but you may be able to install the CentOS packages on RHEL. Refer to the Install Docker Engine on CentOS page for details.

• Is the docker package available for Red Hat Enterprise Linux 8 and 9?

The docker package is not shipped or supported by Red Hat for Red Hat Enterprise Linux (RHEL) 8 and (RHEL) 9. The docker container engine is replaced by a suite of tools in the Container Tools module.

• Transitioning from Docker to Podman

Podman is an excellent alternative to Docker containers when you need increased security, unique identifier (UID) separation using namespaces, and integration with systemd. In this article, I use real-world examples to show you how to install Podman, use its basic commands, and transition from the Docker command-line interface (CLI) to Podman.

Answered By - mon

Answer Checked By - David Marino (WPSolving Volunteer)