How To Install Docker In CentOS

A while ago, we have published a guide to install Docker on Ubuntu. Today, we will see how to install Docker in CentOS. This method is same for other RPM based distributions like Fedora, RHEL, Scientific Linux, and openSUSE etc. To install Docker on CentOS, your system must meet the following minimum requirements.

1. 64 bit architecture;
2. the Kernel version should be 3.10 or above.
3. Your system should be connected with Internet.

Let us get started.

Install Docker In CentOS

Docker installation is fairly simple and straight forward. Open your Terminal and run the following command as root user.

curl -fsSL https://get.docker.com/ | sh

After installing Docker, run the following commands to enable and start Docker service.

systemctl enable docker

systemctl start docker

Check whether Docker service is running or not with command:

systemctl status docker

Sample would be something like below.

● docker.service - Docker Application Container Engine
 Loaded: loaded (/usr/lib/systemd/system/docker.service; enabled; vendor preset: disabled)
 Active: active (running) since Wed 2017-03-08 14:09:38 IST; 24s ago
 Docs: https://docs.docker.com
 Main PID: 1190 (dockerd)
 Memory: 54.4M
 CGroup: /system.slice/docker.service
 ├─1190 /usr/bin/dockerd
 └─2327 docker-containerd -l unix:///var/run/docker/libcontainerd/d...

Mar 08 14:09:35 server1.ostechnix.local dockerd[1190]: time="2017-03-08T14:09:3...
Mar 08 14:09:35 server1.ostechnix.local dockerd[1190]: time="2017-03-08T14:09:3...
Mar 08 14:09:35 server1.ostechnix.local dockerd[1190]: time="2017-03-08T14:09:3...
Mar 08 14:09:36 server1.ostechnix.local dockerd[1190]: time="2017-03-08T14:09:3...
Mar 08 14:09:37 server1.ostechnix.local dockerd[1190]: time="2017-03-08T14:09:3...
Mar 08 14:09:38 server1.ostechnix.local dockerd[1190]: time="2017-03-08T14:09:3...
Mar 08 14:09:38 server1.ostechnix.local dockerd[1190]: time="2017-03-08T14:09:3...
Mar 08 14:09:38 server1.ostechnix.local dockerd[1190]: time="2017-03-08T14:09:3...
Mar 08 14:09:38 server1.ostechnix.local dockerd[1190]: time="2017-03-08T14:09:3...
Mar 08 14:09:38 server1.ostechnix.local systemd[1]: Started Docker Application ...
Hint: Some lines were ellipsized, use -l to show in full.

As you see above, Docker service is running!

Testing Docker

Let us go ahead, and test whether Docker is working or not.

To do so, run:

docker run hello-world

The above command will download a test Docker image, and execute a sample hello_world program inside the container.

If you see an output something like below, congratulations! Docker is working fine in our CentOS system.

Unable to find image 'hello-world:latest' locally
latest: Pulling from library/hello-world
78445dd45222: Pull complete 
Digest: sha256:c5515758d4c5e1e838e9cd307f6c6a0d620b5e07e6f927b07d05f6d12a1ac8d7
Status: Downloaded newer image for hello-world:latest

Hello from Docker!
This message shows that your installation appears to be working correctly.

To generate this message, Docker took the following steps:
 1. The Docker client contacted the Docker daemon.
 2. The Docker daemon pulled the "hello-world" image from the Docker Hub.
 3. The Docker daemon created a new container from that image which runs the
 executable that produces the output you are currently reading.
 4. The Docker daemon streamed that output to the Docker client, which sent it
 to your terminal.

To try something more ambitious, you can run an Ubuntu container with:
 $ docker run -it ubuntu bash

Share images, automate workflows, and more with a free Docker ID:
 https://cloud.docker.com/

For more examples and ideas, visit:
 https://docs.docker.com/engine/userguide/

To check the Docker version, run:

docker version

Sample output:

Client:
 Version: 17.03.0-ce
 API version: 1.26
 Go version: go1.7.5
 Git commit: 60ccb22
 Built: Thu Feb 23 10:54:03 2017
 OS/Arch: linux/amd64

Server:
 Version: 17.03.0-ce
 API version: 1.26 (minimum version 1.12)
 Go version: go1.7.5
 Git commit: 60ccb22
 Built: Thu Feb 23 10:54:03 2017
 OS/Arch: linux/amd64
 Experimental: false

That’s all for now. Docker is ready to use.

Install Docker Compose

Docker Compose is a tool that can be used to define and run multi-container Docker applications. With Compose, you use a Compose file to configure your application’s services. Then, using a single command, you can create and start all the services from your configuration.

We can install Docker Compose using any one of the following methods.

Method 1:

Run the following command from the Terminal as root user to download Docker Compose binary file:

curl -L "https://github.com/docker/compose/releases/download/1.11.2/docker-compose-$(uname -s)-$(uname -m)" -o /usr/local/bin/docker-compose

Then, apply executable permissions to the binary using command:

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

Method 2:

Alternatively, we can install Docker Compose using PIP. Pip is a python package manager used to install applications written in Python programming language.

On Arch Linux and its derivatives, run the following command to install pip:

sudo pacman -S python-pip

On Debian, Ubuntu, Linux Mint:

sudo apt-get install python-pip

On RHEL, Fedora, CentOS:

sudo yum install python-pip

Or,

sudo dnf install python-pip

On SUSE/openSUSE:

sudo zypper install python-pip

Once pip installed, run the following command to install docker compose. The following command is same for all Linux distributions!

pip install docker-compose

After installing Docker Compose, you can check the version with command:

docker-compose --version

You will see an output something like below.

docker-compose version 1.11.2, build dfed245

We now know how to install Docker and Docker Compose in CentOS. Read the following article to getting started with Docker.

• Getting started with Docker

Also, Download and use the following free EBooks to learn Docker.

That's all for now folks. As you can see installing Docker is not a big deal. Docker is quite easy in terms of installation and usage.

Cheers!