Docker is an open source project which allows the creation and distribution of applications inside containers, which are standardized environments that can be easily replicated, independently from the host system. While in Red Hat Enterprise Linux 7 Docker was officially supported, on the new release of this open source operating system, it has been replaced by a series of other tools developed by Red Hat itself: buildah and podman.
About CentOS 8 DNF Command:
DNF stands for Dandified YUM is a software package manager for RPM-based Linux distributions. It is used to install, update and remove packages in the Fedora/RHEL/CentOS operating system. It is the default package manager of Fedora 22, CentOS8 and RHEL8. DNF is the next generation version of YUM and intended to be the replacement for YUM in RPM-based systems. DNF is powerful and has robust features than you’ll find in yum. DNF makes it easy to maintain groups of packages and capable of automatically resolving dependency issues.
yum install dnf $ dnf --version 4.2.7 Installed: dnf-0:4.2.7-7.el8_1.noarch at Wed 11 Mar 2020 09:23:01 AM GMT Built : CentOS Buildsys <bugs@centos.org> at Thu 19 Dec 2019 03:44:23 PM GMT Installed: rpm-0:4.14.2-25.el8.x86_64 at Wed 11 Mar 2020 01:25:56 PM GMT Built : CentOS Buildsys <bugs@centos.org> at Fri 08 Nov 2019 10:56:14 PM GMT
Installation Steps of Docker CE on CentOS 8 / RHEL 8 Server
By the use of an external repository, however, it’s still possible to install Docker CE (Community Edition). In this tutorial we will see how to install repository to obtain the software because the community version of Docker has no official support for Red Hat Enterprise Linux.
Docker Available Versions
Docker CE (Community Edition)
Enterprise Edition (EE)
In this guide we will learn how to install Docker CE (Community Edition) on CentOS 8 or RHEL 8 Server.
System Requirements for Docker CE
Minimal CentOS 8 / RHEL 8
Sudo or root privileges
Internet Connection
Enable Docker CE Repository
$ sudo dnf config-manager --add-repo=https://download.docker.com/linux/centos/docker-ce.repo Adding repo from: https://download.docker.com/linux/centos/docker-ce.repo
Install Docker CE using dnf command
$ sudo dnf list docker-ce CentOS-8 - AppStream 4.0 kB/s | 4.3 kB 00:01 CentOS-8 - Base 3.5 kB/s | 3.8 kB 00:01 CentOS-8 - Extras 2.7 kB/s | 1.5 kB 00:00 Docker CE Stable - 86_64 24 kB/s | 22 kB 00:00 Available Packages docker-ce.x86_64 3:19.03.7-3.el7 docker-ce-stable $ sudo dnf install docker-ce --nobest -y Docker CE Stable - x86_64 6.6 kB/s | 1.6 kB 00:00 Importing GPG key 0x621E9F35: Userid : "Docker Release (CE rpm) <docker@docker.com>" Fingerprint: 060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35 From : https://download.docker.com/linux/centos/gpg Key imported successfully Running transaction check Transaction check succeeded. Running transaction test Transaction test succeeded. Running transaction Preparing : 1/1 Installing : docker-ce-cli-1:19.03.7-3.el7.x86_64 1/4 Running scriptlet: docker-ce-cli-1:19.03.7-3.el7.x86_64 1/4 Installing : containerd.io-1.2.0-3.el7.x86_64 2/4 Running scriptlet: containerd.io-1.2.0-3.el7.x86_64 2/4 Running scriptlet: libcgroup-0.41-19.el8.x86_64 3/4 Installing : libcgroup-0.41-19.el8.x86_64 3/4 Running scriptlet: libcgroup-0.41-19.el8.x86_64 3/4 Running scriptlet: docker-ce-3:18.09.1-3.el7.x86_64 4/4 Installing : docker-ce-3:18.09.1-3.el7.x86_64 4/4 Running scriptlet: docker-ce-3:18.09.1-3.el7.x86_64 4/4 Verifying : libcgroup-0.41-19.el8.x86_64 1/4 Verifying : containerd.io-1.2.0-3.el7.x86_64 2/4 Verifying : docker-ce-3:18.09.1-3.el7.x86_64 3/4 Verifying : docker-ce-cli-1:19.03.7-3.el7.x86_64 4/4 Installed: docker-ce-3:18.09.1-3.el7.x86_64 libcgroup-0.41-19.el8.x86_64 containerd.io-1.2.0-3.el7.x86_64 docker-ce-cli-1:19.03.7-3.el7.x86_64 Skipped: docker-ce-3:19.03.7-3.el7.x86_64 Complete!
Start and Enable the Docker Daemon
Once docker-ce is installed, we must start and enable the docker daemon, so that it will be also launched automatically at boot. The command we need to run is the following:
$ sudo systemctl enable --now docker
At this point, we can confirm that the daemon is active by running:
$ sudo systemctl start docker $ systemctl is-active docker active
Similarly, we can check that it is enabled at boot, by running:
$ systemctl is-enabled docker enabled
Run the following command to verify installed docker version
$ docker --version Docker version 19.03.7, build 7141c199a2
Verify and Test Docker CE Engine
$ sudo docker run centos Unable to find image 'centos:latest' locally latest: Pulling from library/centos 8a29a15cefae: Pull complete Digest: sha256:fe8d824220415eed5477b63addf40fb06c3b049404242b31982106ac204f6700 Status: Downloaded newer image for centos:latest $ sudo docker ps -a CONTAINER ID IMAGE COMMAND CREATED STATUS PORTS NAMES 53e807058dd5 centos "/bin/bash" 41 seconds ago Exited (0) 39 seconds ago hopeful_dirac $ sudo docker images REPOSITORY TAG IMAGE ID CREATED SIZE centos latest 470671670cac 7 weeks ago 237MB $ sudo docker run -it centos [root@cd4f766147f3 /]#
Install Docker Compose
$ sudo curl -L "https://github.com/docker/compose/releases/download/1.25.0/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose
% Total % Received % Xferd Average Speed Time Time Time Current
Dload Upload Total Spent Left Speed
100 617 100 617 0 0 638 0 --:--:-- --:--:-- --:--:-- 638
100 16.2M 100 16.2M 0 0 988k 0 0:00:16 0:00:16 --:--:-- 1199k
Set the executable permission to docker-compose binary.
$ sudo chmod +x /usr/local/bin/docker-compose
Check the docker compose version with following command.
$ docker-compose --version docker-compose version 1.25.0, build 0a186604
Conclusion:
Basically, that’s all you need to know about Docker setup on CentOS 8 and RHEL 8. There are more tutorials that will go into deeper explanation of using Docker thoroughly, but this is a simple article to just get familiar with the concept of Docker.
