#docker #ubuntu 


```table-of-contents
```
Installing **Docker** and **Docker Compose** on **Ubuntu** involves a few straightforward steps. It's generally best to install from Docker's official repositories to ensure you have the latest version.

---

## 🐋 Step 1: Uninstall Old Versions (If Applicable)

First, remove any existing, potentially conflicting Docker packages:

Bash

```
for pkg in docker.io docker-engine docker-ce docker.io docker-compose docker-compose-v2; do sudo apt-get remove $pkg; done
```

---

## 🛠️ Step 2: Set Up Docker's Repository

You need to set up the repository to allow `apt` to use a repository over HTTPS:

1. **Update the `apt` package index:**
    
    Bash
    
    ```
    sudo apt-get update
    ```
    
2. **Install necessary packages:**
    
    Bash
    
    ```
    sudo apt-get install ca-certificates curl
    ```
    
3. **Add Docker's official GPG key:**
    
    Bash
    
    ```
    sudo install -m 0755 -d /etc/apt/keyrings
    sudo curl -fsSL https://download.docker.com/linux/ubuntu/gpg -o /etc/apt/keyrings/docker.asc
    sudo chmod a+r /etc/apt/keyrings/docker.asc
    ```
    
4. **Add the repository to `apt` sources:**
    
    Bash
    
    ```
    echo \
      "deb [arch=$(dpkg --print-architecture) signed-by=/etc/apt/keyrings/docker.asc] https://download.docker.com/linux/ubuntu \
      $(. /etc/os-release && echo "$VERSION_CODENAME") stable" | \
      sudo tee /etc/apt/sources.list.d/docker.list > /dev/null
    ```
    

---

## 🚀 Step 3: Install Docker Engine

Now that the repository is set up, you can install the Docker Engine packages:

1. **Update the `apt` package index again:**
    
    Bash
    
    ```
    sudo apt-get update
    ```
    
2. **Install the Docker packages:**
    
    Bash
    
    ```
    sudo apt-get install docker-ce docker-ce-cli containerd.io docker-buildx-plugin docker-compose-plugin
    ```
    
    (Note: The `docker-compose-plugin` installs **Docker Compose V2**, which is used via the command `docker compose` instead of `docker-compose`).
    

---

## ✅ Step 4: Verify the Installation

Check that the Docker Engine is running and that the installation was successful by running the test image:

Bash

```
sudo docker run hello-world
```

If successful, this command downloads a test image and runs it, printing an informational message before exiting.

---

## 👤 Step 5: Manage Docker as a Non-Root User (Recommended)

By default, running Docker commands requires `sudo`. To run Docker without `sudo`, you can add your user to the **`docker` group**:

1. **Add your user to the `docker` group:**
    
    Bash
    
    ```
    sudo usermod -aG docker $USER
    ```
    
2. **Log out and log back in** (or restart your terminal session, or run `newgrp docker`) for the changes to take effect.
    
3. **Verify without `sudo`:**
    
    Bash
    
    ```
    docker run hello-world
    ```
    

You should now have **Docker Engine** and **Docker Compose (V2)** installed and ready to use!

Would you like to know some basic **Docker commands** or learn how to write a simple **`docker-compose.yml`** file?