Centos Docker Install

2/12/2022by admin

Installing Docker on Ubuntu is simple because Ubuntu provides Docker in its repositories. However, Docker is not available in CentOS's default repositories.

0 OK docker.io docker.io/timhughes/centos Centos with systemd installed and running 0 OK docker.io docker.io/ustclug/centos USTC centos 0 OK Congratulations! Now, you know “ How to install Docker on CentOS 7”. Install Docker CE on CentOS 8 Option 1: Skip Packages with Broken Dependencies. An efficient solution is to allow your CentOS 8 system to install the version that meets the criteria best, using the -nobest command: sudo dnf install docker-ce -nobest. The installation skips the latest candidates and installs the most appropriate version with.

Fret not, there are three ways you can install docker on a CentOS Linux system.

To install a specific version of Docker, start by listing the available releases. Type the following in your terminal window: yum list docker-ce -showduplicates sort –r. The system should give you a list of different versions from the repositories you have enabled above. Install the selected Docker version with the command. To install the latest version of Docker, run the commands below. If you want to install a specific Docker version, skip this step and go to the next one. Sudo apt updatesudo apt install docker-ce docker-ce-cli containerd.io; To install a specific version, first list all the available versions in the Docker repository. The steps shared here are for the installation of Docker CE on RHEL 7 Linux. Docker is the main dominant container runtime engine used for Development and running of micro-serviced applications in production.

Centos docker installation
  • Using docker's repository
  • Downloading the RPM
  • Using helper scripts

Here, I'll walk you through the installation process of Docker CE using docker's RPM repository.

Docker CE stands for Docker Community Edition. This is the free and open source version of Docker. There is Docker EE (Enterprise Edition) with paid support. Most of the world uses Docker CE and it is often considered synonymous to Docker.

Installing Docker on CentOS

Install Docker Ce Centos 8 Iso

Before going any further, make sure you have the system updated. You can update the CentOS using:

Step 1: Add the official repository

Add docker's official repository using the following command

You should also update the package cache after adding a new repository:

Step 2: Install Docker CE

The trouble with using a custom repository is that it may have dependency issue if you try installing the latest version of docker-ce.

For example, when I check the available versions of docker-ce with this command:

I got docker-ce-3:19.03.9-3.el7 as the latest version. But the problem in installing the latest version is that it depends on containerd.io version >=1.2.2-3. Now, this version of containerd.io is not available in CentOS 8.

To avoid this dependency cycle and battling them manually, you can use the --nobest option of the dnf command.

It will check the latest version of docker-ce but when it finds the dependency issue, it checks the next available version of docker-ce. Basically, it helps you automatically install the most suitable package version with all the dependencies satisfied.

To install docker in CentOS without getting a migraine, try this command and see the magic unfold on your terminal screen:

You'll be prompted to import a GPG key, make sure the key matches to 060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35 before entering 'y'.

containerd.io is a daemon for managing containers. Docker is just one form of Linux containers. To make the various types of container images portable, Open Container Initiative has defined some standards. containerd is used for managing the container images conforming to OCI standard.

Setting up docker on CentOS

Alright! You have docker installed but it's not yet ready to be used yet. You'll have to do some basic configurations before it can be used smoothly.

Run docker without sudo

You can run docker without any sudo privileges by adding your user to the docker group.

The docker group should already exist. Check that using the following command:

If this outputs nothing, create the docker group using groupadd command like this:

Now add your user to the docker group using the usermod command:

Change the user_name in the above command with the intended user name.

Now log out and log back in for the group change to take effect.

Start docker daemon

Docker is installed. Your user has been added to the docker group. But that's not enough to run docker yet.

Before you can run any container, the docker daemon needs to be running. The docker daemon is the program that manages all the containers, volumes, networks etc. In other words, the daemon does all the heavy lifting.

Start the docker daemon using:

You can also enable docker daemon to start automatically at boot time:

Verify docker installation by running a sample container

Everything is done. It's time to test whether the installation was successful or not by running a docker container.

To verify, you can run the cliché hello-world docker container. It is a tiny docker image and perfect for quickly testing a docker installation.

If everything is fine, you should see an output like this:

Here's what the command is doing behind the hood:

  • The docker client, i.e. the command line tool that you just used, contacted the docker daemon.
  • The daemon looked for hello-world docker image in the local system. Since it doesn't find the image, it pulls it from Docker Hub.
  • The engine creates the container with all the options you provided through the client's command line options.

This hello-world image is used just for testing a docker installation. If you want a more useful container, you can try running Nginx server in a container like this:

Once the command is done running, open up a browser and go to http://your_ip_address:56788. I hope you know how to know your IP address in Linux.

You should see nginx server running. You can stop the container now.

Install Docker Ce On Centos 8

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Centos Docker Install Ssh

Docker is an open-source project that automates the deployment of application inside the software container. The container allows the developer to package up all project resources such as libraries, dependencies, assets etc. Docker is written in Go Programming language and is developed by Dotcloud. It is basically a container engine which uses the Linux Kernel features like namespaces and control groups to create containers on top of an operating system and automates the application deployment on the container.

Installing Docker

Before installing Docker on CentOS, it is required to update CentOS packages. To update the packages, use the following commands-

The sample output should be like this –

To install Docker, use the following command –

The sample output should be like this –

Starting Docker

To start Docker at boot, use the following command –

The sample output should be like this –

Docker Install Linux

To start the Docker, use the following command –

Centos 7 Docker Install

To find the status of docker, use the following command –

The sample output should be like this –

Downloading Docker container for CentOS

To download Docker container, use the following command –

The sample output should be like this –

Running a Docker Container

To run a docker, it should require a basic CentOS container with a bash shell. To run a Docker, use the following command –

The above command enters the user to a bash shell inside centOS docker container. To exit from the Docker, use Ctrl+p or Ctrl+q shortcuts. There are many communities which are already included in Docker container that can be found through a search.

Centos Docker Installation

For example, to search CentOS community, use the following command –

The sample output should be like this –

Congratulations! Now, you know “ How to install Docker on CentOS 7”. We’ll learn more about these types of commands in our next Linux post. Keep reading!

Centos Docker Install Ssh

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