Learn how to install Docker in Linux. Docker is the next step of virtualization which does Operating system level virtualization also known as containerization.
In this article, we will walk you through the procedure to install Docker in any Linux distro like RHEL, SUSE, OEL, CentOS, Debian, Fedora, Ubuntu, etc. Sometimes your package manager like YUM or apt-get may offer package docker* to install docker on your server but it’s always good to get a fresh Docker setup. Since Docker is changing fast and it’s always advisable to install the latest version of Docker which might not be available with your package manager.
Read all docker or containerization related articles here from KernelTalk’s archives.
Install docker using package
If your package manager has a Docker package available to install then it’s an easy way to get Docker on your system.
Before going got Docker installation you should install below packages on your system to use the full flexible functionality of Docker. These packages are not dependencies but its good to have them pre-installed so that all Docker functions/drivers you can use.
- For CenOs, Redhat etc YUM based systems –
yum-utilsdevice-mapper-persistent-datalvm2 - For Debian, Ubuntu etc apt based systems –
apt-transport-httpsca-certificatescurlsoftware-properties-common
But you may not be getting the latest version of Docker in this case. You can install a package simply using yum or apt-get command. Below sample output for your reference from the OpenSuse server.
root@kerneltalks # zypper in docker
Building repository 'openSUSE-13.2-Update' cache .................................................................................................................[done]
Retrieving repository 'openSUSE-13.2-Update-Non-Oss' metadata ....................................................................................................[done]
Building repository 'openSUSE-13.2-Update-Non-Oss' cache .........................................................................................................[done]
Loading repository data...
Reading installed packages...
Resolving package dependencies...
The following NEW package is going to be installed:
docker
1 new package to install.
Overall download size: 6.2 MiB. Already cached: 0 B After the operation, additional 22.9 MiB will be used.
Continue? [y/n/? shows all options] (y): y
Retrieving package docker-1.9.1-56.1.x86_64 (1/1), 6.2 MiB ( 22.9 MiB unpacked)
Retrieving: docker-1.9.1-56.1.x86_64.rpm .............................................................................................................[done (2.5 MiB/s)]
Checking for file conflicts: .....................................................................................................................................[done]
(1/1) Installing: docker-1.9.1-56.1 ..............................................................................................................................[done]
Additional rpm output:
creating group docker...
Updating /etc/sysconfig/docker...
Install docker using the script
In the below procedure, we will be using the script from Docker’s official website which will scan your system for details and automatically fetch the latest and compatible docker version for your system and installs it. We will be fetching script from this docker URL and using it to install the latest Docker on the list of Linux distros.
Fetch the latest script from docker official website using curl. If you read this script, SUPPORT_MAP variable shows the list of Linux distros this script support. If you are running any other Linux version than listed here then this method won’t be useful for you.
root@kerneltalks # curl -fsSL get.docker.com -o get-docker.sh
root@kerneltalks # ls -lrt
-rw-r--r--. 1 root root 13847 May 30 18:59 get-docker.sh
Now we have latest get-docker.sh script from docker official website on our server. Now, you just have to run the script and it will do the rest!
# sh get-docker.sh
# Executing docker install script, commit: 36b78b2
+ sh -c 'yum install -y -q yum-utils'
Package yum-utils-1.1.31-45.el7.noarch already installed and latest version
+ sh -c 'yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo'
Loaded plugins: fastestmirror
adding repo from: https://download.docker.com/linux/centos/docker-ce.repo
grabbing file https://download.docker.com/linux/centos/docker-ce.repo to /etc/yum.repos.d/docker-ce.repo
repo saved to /etc/yum.repos.d/docker-ce.repo
+ '[' edge '!=' stable ']'
+ sh -c 'yum-config-manager --enable docker-ce-edge'
Loaded plugins: fastestmirror
========================================================================= repo: docker-ce-edge =========================================================================
[docker-ce-edge]
async = True
bandwidth = 0
base_persistdir = /var/lib/yum/repos/x86_64/7
baseurl = https://download.docker.com/linux/centos/7/x86_64/edge
cache = 0
cachedir = /var/cache/yum/x86_64/7/docker-ce-edge
check_config_file_age = True
compare_providers_priority = 80
cost = 1000
deltarpm_metadata_percentage = 100
deltarpm_percentage =
enabled = 1
enablegroups = True
exclude =
failovermethod = priority
ftp_disable_epsv = False
gpgcadir = /var/lib/yum/repos/x86_64/7/docker-ce-edge/gpgcadir
gpgcakey =
gpgcheck = True
gpgdir = /var/lib/yum/repos/x86_64/7/docker-ce-edge/gpgdir
gpgkey = https://download.docker.com/linux/centos/gpg
hdrdir = /var/cache/yum/x86_64/7/docker-ce-edge/headers
http_caching = all
includepkgs =
ip_resolve =
keepalive = True
keepcache = False
mddownloadpolicy = sqlite
mdpolicy = group:small
mediaid =
metadata_expire = 21600
metadata_expire_filter = read-only:present
metalink =
minrate = 0
mirrorlist =
mirrorlist_expire = 86400
name = Docker CE Edge - x86_64
old_base_cache_dir =
password =
persistdir = /var/lib/yum/repos/x86_64/7/docker-ce-edge
pkgdir = /var/cache/yum/x86_64/7/docker-ce-edge/packages
proxy = False
proxy_dict =
proxy_password =
proxy_username =
repo_gpgcheck = False
retries = 10
skip_if_unavailable = False
ssl_check_cert_permissions = True
sslcacert =
sslclientcert =
sslclientkey =
sslverify = True
throttle = 0
timeout = 30.0
ui_id = docker-ce-edge/x86_64
ui_repoid_vars = releasever,
basearch
username =
+ sh -c 'yum makecache'
Loaded plugins: fastestmirror
base | 3.6 kB 00:00:00
docker-ce-edge | 2.9 kB 00:00:00
docker-ce-stable | 2.9 kB 00:00:00
epel/x86_64/metalink | 21 kB 00:00:00
extras | 3.4 kB 00:00:00
updates | 3.4 kB 00:00:00
(1/15): docker-ce-stable/x86_64/filelists_db | 7.7 kB 00:00:03
(2/15): base/7/x86_64/other_db | 2.5 MB 00:00:04
(3/15): docker-ce-edge/x86_64/filelists_db | 9.6 kB 00:00:04
(4/15): docker-ce-edge/x86_64/other_db | 62 kB 00:00:04
(5/15): docker-ce-stable/x86_64/other_db | 66 kB 00:00:00
(6/15): base/7/x86_64/filelists_db | 6.9 MB 00:00:05
(7/15): epel/x86_64/filelists_db | 10 MB 00:00:01
(8/15): epel/x86_64/prestodelta | 2.8 kB 00:00:00
(9/15): epel/x86_64/other_db | 3.1 MB 00:00:01
(10/15): extras/7/x86_64/prestodelta | 48 kB 00:00:02
(11/15): extras/7/x86_64/other_db | 95 kB 00:00:02
(12/15): extras/7/x86_64/filelists_db | 519 kB 00:00:02
(13/15): updates/7/x86_64/filelists_db | 1.3 MB 00:00:02
(14/15): updates/7/x86_64/prestodelta | 231 kB 00:00:00
(15/15): updates/7/x86_64/other_db | 228 kB 00:00:00
Loading mirror speeds from cached hostfile
* base: mirror.genesisadaptive.com
* epel: s3-mirror-us-east-1.fedoraproject.org
* extras: mirror.math.princeton.edu
* updates: mirror.metrocast.net
Metadata Cache Created
+ sh -c 'yum install -y -q docker-ce'
If you would like to use Docker as a non-root user, you should now consider
adding your user to the "docker" group with something like:
sudo usermod -aG docker your-user
Remember that you will have to log out and back in for this to take effect!
WARNING: Adding a user to the "docker" group will grant the ability to run
containers which can be used to obtain root privileges on the
docker host.
Refer to https://docs.docker.com/engine/security/security/#docker-daemon-attack-surface
for more information.
If you observe the above output then you will get to know that script will detect your OS and will download, configure, and use supported repo to install Docker on your machine. It also notifies you to add non-root user to group docker so that he/she can run docker commands with root privileges.
You can download and run the script this in a single command as well like below –
root@kerneltalks # curl -fsSL get.docker.com -o - get-docker.sh | bash -s
If you are running the script on un-supported Linux version (which is not mentioned in SUPPORT_MAP list) then you will see below error.
root@kerneltalks # sh get-docker.sh
Executing docker install script, commit: 36b78b2
Either your platform is not easily detectable or is not supported by this
installer script.
Please visit the following URL for more detailed installation instructions:
https://docs.docker.com/engine/installation/
If you are on RHEL, SLES (basically Enterprise Linux editions) then only Docker EE i.e. Enterprise Edition (paid) is supported on them. You will need to purchase appropriate subscriptions to use them. You will see below message –
# sh get-docker.sh
# Executing docker install script, commit: 36b78b2
WARNING: rhel is now only supported by Docker EE
Check https://store.docker.com for information on Docker EE
Install with help from docker store
If both above methods are not suitable for you then you can always opt for the last method. Head to Docker online store. Goto Docker CE i.e. Community Edition (the free one) and choose your Linux distro. Currently, they have listed AWS, Azure, Fedora, CentOS, Ubuntu & Debian. Click on your choice, head to Resources tab, and click Detailed installation instructions. You will be redirected to appropriate documents on Docker documents which have detailed step by step commands to perform a clean install of Docker on Linux of your choice! Or you can always head to this home page of installation and choose your host.
Check if Docker is installed
Finally, you have to check if Docker is installed on the system. To check if docker is installed, simply run the command docker version
root@kerneltalks # docker version
Client:
Version: 18.05.0-ce
API version: 1.37
Go version: go1.9.5
Git commit: f150324
Built: Wed May 9 22:14:54 2018
OS/Arch: linux/amd64
Experimental: false
Orchestrator: swarm
Cannot connect to the Docker daemon at unix:///var/run/docker.sock. Is the docker daemon running?
The last line in the above output shows that the Docker service is not yet running on the server. You can start the service and then the output will show your Docker server details as well.
root@kerneltalks # service docker start
root@kerneltalks # docker version
Client:
Version: 18.05.0-ce
API version: 1.37
Go version: go1.9.5
Git commit: f150324
Built: Wed May 9 22:14:54 2018
OS/Arch: linux/amd64
Experimental: false
Orchestrator: swarm
Server:
Engine:
Version: 18.05.0-ce
API version: 1.37 (minimum version 1.12)
Go version: go1.9.5
Git commit: f150324
Built: Wed May 9 22:18:36 2018
OS/Arch: linux/amd64
Experimental: false
So, now you have successfully installed Docker on your machine and started the Docker server. You are yet to create containers in it!
Setting up docker for non-root user
For non-root user to use Docker, you need to add the user into a group called docker. This group is automatically gets created when you install Docker.
root@kerneltalks # usermod -aG <user> docker
Run above command to add non-root user in docker group and then that user will be able to run all docker commands without root privileges.
Also, you need to make sure that docker services start automatically when the server reboots. Since system control systemctl is becoming standard on all latest Linux versions, below command will suit on nearly major Linux distros
root@kerneltalks # systemctl enable docker
This command will enable docker to run with system boot and hence no root intervention needed when the system reboots. Non-root users will continue to use docker even after a reboot.
Try Docker without installing!
If you want to try Docker without installing it on your machine then just head to Play with Docker website and you will be able to spin up machines having Docker in it. You can try Docker commands in it from your web browser!
The only limitation they have is your session will be auto closed after 4 hours. You have a clock ticking in your browser window set to 4 hours once you log in.
