(Last Updated On: March 29, 2019)

Can I install Docker on RHEL / CentOS 8?, How to install Docker Compose on RHEL / CentOS 8?, Install Docker & Docker Compose on CentOS 8?. This guide will walk you through the installation of Docker and Docker Compose on RHEL 8 / CentOS 8. Docker is not officially supported on RHEL 8 as it has been replaced with Red Hat tools – buildah and podman. We will cover buildah and podman in a separate article.

Red Hat Enterprise Linux 8 (RHEL 8) New Features & Review

But what if you use Docker every single day and can’t switch to buildah and podman immediately?, don’t worry since there is a way to install Docker and Docker Compose on RHEL 8 / CentOS 8. Docker is a tool that enables you to create, deploy and run your applications in containers. Containers allow a Developer to package an application with its dependencies and ship it out as a single package. Containers are often used in Microservices environments.

Docker Components / Terminologies

There area a number of Docker specific jargon that we need to clarify before diving into installation and usage examples. Below are commonly used terminologies in Docker ecosystem.

  • Docker daemon: This is also called Docker Engine, it is a background process which runs on the host system responsible for building and running of containers.
  • Docker Client: This is a command line tool used by the user to interact with the Docker daemon.
  • Docker Image: An image is an immutable file that’s essentially a snapshot of a container. A docker image has a file system and application dependencies required for running applications.
  • Docker container: This is a running instance of a docker image with an application and its dependencies. Each container has a unique process ID and isolated from other containers. The only thing containers share is the Kernel.
  • Docker registry: This is an application responsible for managing storage and delivery of Docker container images. It can be private or public.

Install Docker CE on RHEL 8 / CentOS 8

So far we have covered docker introduction and terminologies. We should be ready to install Docker CE on RHEL 8 / CentOS 8. We will start with the installation of Docker then Docker Compose.

There are two editions of Docker available.

  • Community Edition (CE): ideal for individual developers and small teams looking to get started with Docker and experimenting with container-based apps.
  • Enterprise Edition (EE): Designed for enterprise development and IT teams who build, ship, and run business-critical applications in production at scale.

The Docker Enterprise Edition requires an active license to use. In this guide, we will install Docker CE on RHEL 8. Let’s add Docker repository before we can install it.

sudo curl  https://download.docker.com/linux/centos/docker-ce.repo -o /etc/yum.repos.d/docker-ce.repo

This command will download Docker repository file to /etc/yum.repos.d/docker-ce.repo. Let’s update RPM index cache.

$ sudo yum makecache 
Updating Subscription Management repositories.
Updating Subscription Management repositories.
Docker CE Stable - x86_64 6.1 kB/s | 14 kB 00:02
Red Hat Enterprise Linux 8 for x86_64 - AppStream Beta (RPMs) 1.8 kB/s | 4.1 kB 00:02
Red Hat Enterprise Linux 8 for x86_64 - BaseOS Beta (RPMs) 3.5 kB/s | 4.1 kB 00:01
Metadata cache created.

Finally install Docker CE by running the command below in your terminal.

sudo yum -y  install docker-ce

Start and enable Docker Service to start at boot.

sudo systemctl enable --now docker

The docker service status should indicate running.

$ systemctl status  docker
● docker.service - Docker Application Container Engine
Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
Active: active (running) since Sun 2019-03-10 09:52:54 EAT; 29s ago
Docs: https://docs.docker.com
Main PID: 2875 (dockerd)
Tasks: 21 (limit: 11510)
Memory: 48.3M
CGroup: /system.slice/docker.service
├─2875 /usr/bin/dockerd
└─2882 docker-containerd --config /var/run/docker/containerd/containerd.toml
Mar 10 09:52:54 rhel8.local dockerd[2875]: time="2019-03-10T09:52:54.261477553+03:00" level=info msg="ClientConn switching balancer to \"pick_first\"">
Mar 10 09:52:54 rhel8.local dockerd[2875]: time="2019-03-10T09:52:54.261506651+03:00" level=info msg="pickfirstBalancer: HandleSubConnStateChange: 0xc>
Mar 10 09:52:54 rhel8.local dockerd[2875]: time="2019-03-10T09:52:54.261707466+03:00" level=info msg="pickfirstBalancer: HandleSubConnStateChange: 0xc>
Mar 10 09:52:54 rhel8.local dockerd[2875]: time="2019-03-10T09:52:54.261722124+03:00" level=info msg="Loading containers: start."
Mar 10 09:52:54 rhel8.local dockerd[2875]: time="2019-03-10T09:52:54.637205789+03:00" level=info msg="Default bridge (docker0) is assigned with an IP >
Mar 10 09:52:54 rhel8.local dockerd[2875]: time="2019-03-10T09:52:54.835734889+03:00" level=info msg="Loading containers: done."
Mar 10 09:52:54 rhel8.local dockerd[2875]: time="2019-03-10T09:52:54.857760401+03:00" level=info msg="Docker daemon" commit=d7080c1 graphdriver(s)=ove>
Mar 10 09:52:54 rhel8.local dockerd[2875]: time="2019-03-10T09:52:54.858095579+03:00" level=info msg="Daemon has completed initialization"
Mar 10 09:52:54 rhel8.local dockerd[2875]: time="2019-03-10T09:52:54.915887172+03:00" level=info msg="API listen on /var/run/docker.sock"
Mar 10 09:52:54 rhel8.local systemd[1]: Started Docker Application Container Engine.

The docker group is created, but no users are added to the group. Add your user to this group to run docker commands without sudo.

$ sudo usermod -aG docker $(whoami)
$ id $USER
uid=1000(jmutai) gid=1000(jmutai) groups=1000(jmutai),10(wheel),984(docker)

Logout and Login again to use Docker without sudo. The version of Docker installed can be checked with:

$ docker version
Client:
Version: 18.06.3-ce
API version: 1.38
Go version: go1.10.3
Git commit: d7080c1
Built: Wed Feb 20 02:26:51 2019
OS/Arch: linux/amd64
Experimental: false

Server:
Engine:
Version: 18.06.3-ce
API version: 1.38 (minimum version 1.12)
Go version: go1.10.3
Git commit: d7080c1
Built: Wed Feb 20 02:28:17 2019
OS/Arch: linux/amd64
Experimental: false

Pull Test docker image

The last step is to test your installation by downloading a test docker container.

$ docker pull alpine
Using default tag: latest
latest: Pulling from library/alpine
8e402f1a9c57: Pull complete
Digest: sha256:644fcb1a676b5165371437feaa922943aaf7afcfa8bfee4472f6860aad1ef2a0
Status: Downloaded newer image for alpine:latest

List downloaded images.

$ docker images
REPOSITORY TAG IMAGE ID CREATED SIZE
alpine latest 5cb3aa00f899 2 days ago 5.53MB
hello-world latest fce289e99eb9 2 months ago 1.84kB

Verify that Docker CE is working correctly by running the alpine container from downloaded image.

$ docker run -it --rm alpine /bin/sh
/ # apk update
fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/main/x86_64/APKINDEX.tar.gz
fetch http://dl-cdn.alpinelinux.org/alpine/v3.9/community/x86_64/APKINDEX.tar.gz
v3.9.2-1-g592d872fb8 [http://dl-cdn.alpinelinux.org/alpine/v3.9/main]
v3.9.2-2-ge7dc3349a9 [http://dl-cdn.alpinelinux.org/alpine/v3.9/community]
OK: 9754 distinct packages available
/ # exit

Install Docker Compose on RHEL 8 / CentOS 8

We have Docker installed and running, let’s now change gear to Docker Compose. Docker Compose is a tool used to define and run multi-container Docker applications.

The application services are configured using a Compose file. Unlike running docker commands, a single command is all that’s required to create and start all the services from your configuration. Docker Compose is a great tool for development, testing, and staging environments, as well as CI workflows.

Download Docker Compose on RHEL 8 / CentOS 8

Please check the latest release of Docker Compose on the Official Compose releases page before downloading. As of this writing, the latest release is “1.23.2”.

export VER="1.23.2"

Download latest stable version saved to variable VER.

sudo curl -L "https://github.com/docker/compose/releases/download/${VER}/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

The command above will save the file to /usr/local/bin/docker-compose. Apply executable permissions to the binary:

sudo chmod +x /usr/local/bin/docker-compose

Display Docker compose version.

$ docker-compose --versioncontaconta
docker-compose version 1.23.2, build 1110ad01

Configure Compose Command-line completion

Compose has command completion for the bash and zsh shell.

For Bash users

Place the completion script in /etc/bash_completion.d/.

sudo curl -L https://raw.githubusercontent.com/docker/compose/${VER}/contrib/completion/bash/docker-compose -o /etc/bash_completion.d/docker-compose

Source the file or re-login to enjoy completion feature.

source /etc/bash_completion.d/docker-compose

For Zsh users

Download the completion script in your ~/.zsh/completion/

mkdir -p ~/.zsh/completion
curl -L https://raw.githubusercontent.com/docker/compose/${VER}/contrib/completion/zsh/_docker-compose > ~/.zsh/completion/_docker-compose

Include the directory in your $fpath by adding in ~/.zshrc:

fpath=(~/.zsh/completion $fpath)

Make sure compinit is loaded or do it by adding in ~/.zshrc:

autoload -Uz compinit && compinit -i

Then reload your shell:

exec $SHELL -l

For the sake of keeping this guide brief, we won’t dive into Docker compose usage. I’ll recommend you go through Official Docker documentation and Docker Compose documentation to learn more.

Docker UI

If you need Docker management UI which allows you to easily manage your different Docker hosts and containers, please give Portainer a try. It is easy to install and use.

How to Install Portainer Docker UI manager

Monitoring Docker containers

Monitoring Docker containers can be achieved by using Monitoring tools such as Netdata or Ctop or Prometheus and Grafana. Below guides should be helpful.

Ctop – Top command for container metrics

How to Install Netdata on RHEL 8 / CentOS 8