# How to Install?

## [How to install?](https://docs.docker.com/v17.09/engine/installation/linux/docker-ce/ubuntu/#install-docker-ce-1)

This process will help you to guide you to install docker on a Ubuntu machine.

### Install Docker from Ubuntu Repository

You can use apt-get command to install the Docker from Ubuntu base repository.

```
$ sudo apt install docker.io
```

Start the docker service and enable it to start automatically on system startup.

```
$ sudo systemctl start docker
$ sudo systemctl enable docker
```

Now, verify the docker version.

```
$ docker --version
$ Docker version 17.12.1-ce, build 7390fc6
```

### Install Docker from Official Docker Repository

#### Prerequisites

Uninstall the older versions of Docker package, named docker or docker-engine or docker.io along with associated dependencies.

If the system does not have Docker packages, skip the below step.

```
sudo apt -y remove docker docker-engine docker.io
```

Contents such as images, volumes, and networks under /var/lib/docker/ are preserved.

#### Setup

Setup docker, open terminal and execute:

```
sudo apt update
```

Install the below packages to ensure the `apt` work with https method, and CA certificates are installed.

```
sudo apt install -y apt-transport-https software-properties-common ca-certificates curl wget
```

Add the GPG key for Docker repository on your system.

```
wget https://download.docker.com/linux/ubuntu/gpg 
sudo apt-key add gpg
```

Now, add the official Docker repository by running the below command in the terminal.

```
echo "deb [arch=amd64] https://download.docker.com/linux/ubuntu bionic stable" | sudo tee /etc/apt/sources.list.d/docker.list
```

Update the apt database.

```
sudo apt update
```

Make sure you are installing the docker package from the official repository.

```
sudo apt-cache policy docker-ce
```

**Output:**

```
docker-ce:
  Installed: (none)
  Candidate: 18.03.1~ce~3-0~ubuntu
  Version table:
     18.03.1~ce~3-0~ubuntu 500
        500 https://download.docker.com/linux/ubuntu bionic/stable amd64 Packages
```

More info: <https://docs.docker.com/v17.09/engine/installation/linux/docker-ce/ubuntu/#install-docker-ce-1>

## Mac OS

Open a terminal an execute the following command:

```
brew cask install docker
```

Then launch the **Docker** app. Click next. It will ask for privileged access. Confirm. A whale icon should appear in the top bar. Click it and wait for "Docker is running" to appear.

You should be able to run`docker`commands now.

```
docker ps
```
