First, in order to ensure the downloads are valid, add the GPG key for the official Docker repository to your system:
curl -fsSL https://download.docker.com/linux/ubuntu/gpg | sudo apt-key add -
Add the Docker repository to APT sources:
sudo add-apt-repository "deb [arch=amd64] https://download.docker.com/linux/ubuntu $(lsb_release -cs) stable"
Next, update the package database with the Docker packages from the newly added repo:
sudo apt-get update
Make sure you are about to install from the Docker repo instead of the default Ubuntu 16.04 repo:
apt-cache policy docker-ce
You should see output similar to the follow:Output of apt-cache policy docker-ce
docker-ce: Installed: (none) Candidate: 18.06.1~ce~3-0~ubuntu Version table: 18.06.1~ce~3-0~ubuntu 500 500 https://download.docker.com/linux/ubuntu xenial/stable amd64 Packages
Notice that docker-ce
is not installed, but the candidate for installation is from the Docker repository for Ubuntu 16.04 (xenial
).
Finally, install Docker:
sudo apt-get install -y docker-ce
Docker should now be installed, the daemon started, and the process enabled to start on boot. Check that it’s running:
sudo systemctl status docker
The output should be similar to the following, showing that the service is active and running:
Output● docker.service - Docker Application Container Engine Loaded: loaded (/lib/systemd/system/docker.service; enabled; vendor preset: enabled) Active: active (running) since Thu 2018-10-18 20:28:23 UTC; 35s ago Docs: https://docs.docker.com Main PID: 13412 (dockerd) CGroup: /system.slice/docker.service ├─13412 /usr/bin/dockerd -H fd:// └─13421 docker-containerd --config /var/run/docker/containerd/containerd.toml
Installing Docker now gives you not just the Docker service (daemon) but also the docker
command line utility, or the Docker client. We’ll explore how to use the docker
command later in this tutorial.
With Docker installed and working, now’s the time to become familiar with the command line utility. Using docker
consists of passing it a chain of options and commands followed by arguments. The syntax takes this form:
docker [option] [command] [arguments]
To view all available subcommands, type:
docker
As of Docker 18.06.1, the complete list of available subcommands includes:
Output attach Attach local standard input, output, and error streams to a running container build Build an image from a Dockerfile commit Create a new image from a container's changes cp Copy files/folders between a container and the local filesystem create Create a new container diff Inspect changes to files or directories on a container's filesystem events Get real time events from the server exec Run a command in a running container export Export a container's filesystem as a tar archive history Show the history of an image images List images import Import the contents from a tarball to create a filesystem image info Display system-wide information inspect Return low-level information on Docker objects kill Kill one or more running containers load Load an image from a tar archive or STDIN login Log in to a Docker registry logout Log out from a Docker registry logs Fetch the logs of a container pause Pause all processes within one or more containers port List port mappings or a specific mapping for the container ps List containers pull Pull an image or a repository from a registry push Push an image or a repository to a registry rename Rename a container restart Restart one or more containers rm Remove one or more containers rmi Remove one or more images run Run a command in a new container save Save one or more images to a tar archive (streamed to STDOUT by default) search Search the Docker Hub for images start Start one or more stopped containers stats Display a live stream of container(s) resource usage statistics stop Stop one or more running containers tag Create a tag TARGET_IMAGE that refers to SOURCE_IMAGE top Display the running processes of a container unpause Unpause all processes within one or more containers update Update configuration of one or more containers version Show the Docker version information wait Block until one or more containers stop, then print their exit codes
To view the switches available to a specific command, type:
docker docker-subcommand --help
To view system-wide information about Docker, use:
docker info
You can read more details form digital ocean and docker’s official doc.