Execute commands in a running container straight from the Docker Dashboard

Developers often need to explore a running container’s contents to understand its current state or debug it when issues arise. With Docker Desktop 4.12, you can quickly start an interactive session in a running container directly through a Docker Dashboard terminal. This easy access lets you run commands without needing an external CLI. 

Opening this integrated terminal is equal to running docker exec -it <container-id> /bin/sh (or docker exec -it cmd.exe if you’re using Windows containers) in your system terminal. Docker detects a running container’s default user from the image’s Dockerfile. If there’s none specified, it defaults to root. Placing this in the Docker Dashboard gives you real-time access to logs and other information about your running containers. 

Your session is persisted if you navigate throughout the Dashboard and return — letting you easily pick up where you left off. The integrated terminal also supports copy, paste, search, and session clearing.

Still want to use your external terminal? No problem. We’ve added two easy ways to launch a session externally.

Option 1: Use the “Open in External Terminal” button straight from this tab. Even if you prefer an integrated terminal, this might help you run commands and watch logs simultaneously, for example.

Option 2: Change your default settings to always open your system default terminal. We’ve added the option to choose what fits your workflow. After applying this setting, the “Open in terminal” button from the Containers tab will always open your system terminal.

Extending Docker Desktop’s integration with containerd

We’re extending Docker Desktop’s integration with containerd to include image management. This integration is available as an opt-in, experimental feature within this latest release.

Docker’s involvement in the containerd project extends all the way back to 2016. Docker has used containerd within the Docker Engine to manage the container lifecycle (creating, starting, and stopping) for a while now! 

This new feature is a step towards deeper containerd integration with Docker Engine. It lets you use containerd to store images and then push and pull them. When enabled in the latest Docker Desktop version, this experimental feature lets you use the following Docker commands with containerd under the hood: run, commit, build, push, load, and save. 

This integration has the following benefits:

• Containerd’s snapshotter implementation helps you quickly plug in new features. One example is using stargz to lazy pull images on startup.
• The containerd content store can natively store multi-platform images and other OCI-compatible objects. This lets you build and manipulate multi-platform images, for example, or leverage other related features.

You can learn more in our recent announcement, which fully explains containerd’s integration with Docker.

Easily discover extensions

We’ve added two new ways to interact with extensions in Docker Desktop 4.12.

Docker Extensions are now available directly within the Docker menu. From there, you can browse the Marketplace for new extensions, manage your installed extensions, or change extension settings. 

You can also search for extensions in the Extensions Marketplace! Narrow things down by name or keyword to find the tool you need.

Two new extensions have also joined the Extensions Marketplace:

Docker Volumes Backup & Share

Docker Volumes Backup & Share lets you effortlessly back up, clone, restore, and share Docker volumes. You can now easily create copies of your volumes and share them through SSH or by pushing them to a registry. Learn more about Volumes Backup & Share on Docker Hub. 

Mini Cluster

Mini Cluster enables developers who work with Apache Mesos to deploy and test their Mesos applications with ease. Learn more about Mini Cluster on Docker Hub.

Try out Dev Environments with Awesome Compose samples

We’ve updated our GitHub Awesome Compose samples to highlight projects that you can easily launch as Dev Environments in Docker Desktop. This helps you quickly understand how to add multi-service applications as Dev Environment projects. Look for the following green icon in the list of Docker Compose application samples:

Here’s our new Awesome Compose/Dev Environments feature in action:

Get started with Docker Desktop 4.12 today

While we’ve explored some headlining features in this release, Docker Desktop 4.12 also adds important security enhancements under the hood. To learn about these fixes and more, browse our full release notes. 

Have any feedback for us? Upvote, comment, or submit new ideas via our in-product links or our public roadmap. 

Looking to become a new Docker Desktop user? Visit our Get Started page to jumpstart your development journey.

However, a challenge arises when you need more than one container. For example, you may develop a web frontend connected to a database backend with both running inside containers. While possible, this approach risks negating some (or all) of that container magic, since we must also consider storage interaction, network interaction, and port configurations. Those added complexities are tricky to navigate.

How Docker Compose Can Help

Docker Compose streamlines many development workloads based around multi-container implementations. One such example is a WordPress website that’s protected with an NGINX reverse proxy, and requires a MySQL database backend.

Alternatively, consider an eCommerce platform with a complex microservices architecture. Each cycle runs inside its own container — from the product catalog, to the shopping cart, to payment processing, and, finally, product shipping. These processes rely on the same database backend container runtime, using a Redis container for caching and performance.

Maintaining a functional eCommerce platform means running several container instances. This doesn’t fully address the additional challenges of scalability or reliable performance.

While Docker Compose lets us create our own solutions, building the necessary Dockerfile scripts and YAML files can take some time. To simplify these processes, Docker introduced the open source Awesome Compose library in March 2020. Developers can now access pre-built samples to kickstart their Docker Compose projects.

What does that look like in practice? Let’s first take a more detailed look at Docker Compose. Next, we’ll explore step-by-step how to spin up a new development project using Awesome Compose.

Having some practical knowledge of Docker concepts and base commands is helpful while following along. However, this isn’t required! If you’d like to brush up or become familiarized with Docker, check out our orientation page and our CLI reference page.

How Docker Compose Works

Docker Compose is based on a compose.yaml file. This file specifies the platform’s building blocks — typically referencing active ports and the necessary, standalone Docker container images.

The diagram below represents snippets of a compose.yaml file for a WordPress site with a MySQL database, a WordPress frontend, and an NGINX reverse proxy:

We’re using three separate Docker images in this example: MySQL, WordPress, and NGINX. Each of these three containers has its own characteristics, such as network ports and volumes.

mysql:
  image: mysql:8.0.28
  container_name: demomysql
  networks:
  	- network
wordpress:
  depends_on:
  	- mysql
  image: wordpress:5.9.1-fpm-alpine
  container_name: demowordpress
  networks:
  	- network
nginx:
  depends_on:
  	- wordpress
  image: nginx:1.21.4-alpine
  container_name: nginx
    ports:
  	- 80:80
  volumes:
  	- wordpress:/var/www/html

Originally, you’d have to use the docker run command to start each individual container. However, this introduces hiccups while managing interactions across each container related to network and storage. It’s much more efficient to consolidate all necessary objects into a docker compose scenario.

To help developers deploy baseline scenarios faster, Docker provides a GitHub repository with several environments, available for you to reuse, called Docker Awesome Compose. Let’s explore how to run these on your own machine.

How to Use Docker Compose

Getting Started

First, you’ll need to download and install Docker Desktop (for macOS, Windows, or Linux). Note that all example outputs in this article, however, come from a Windows Docker host.

You can verify that Docker is installed by running a simple docker run hello-world command:

C:\>docker run hello-world

This should produce the following output, indicating that things are working correctly:

You’ll also need to install Docker Compose on your machine. Similarly, you can verify this installation by running a basic docker compose command, which triggers a corresponding response:

C:\>docker compose

Next, either locally download or clone the Awesome Compose GitHub repository. If you have Git running locally, simply enter the following command:

git clone https://github.com/docker/awesome-compose.git

If you’re not running Git, you can download the Awesome Compose repository as a ZIP file. You’ll then extract it within its own folder.

Adjusting Your Awesome Compose Code

After downloading Awesome Compose, jump into the appropriate subfolder and spin up your sample environment. For this example, we’ll use WordPress with MariaDB. You’ll then want to access your wordpress-mysql subfolder.

Next, open your compose.yaml file within your favorite editor and inspect its contents. Make the following changes in your provided YAML file:

• Update line 9: volumes: - mariadb:/var/lib/mysql
• Provide a complex password for the following variables:
  • MYSQL_ROOT_PASSWORD (line 12)
  • MYSQL_PASSWORD (line 15)
  • WORDPRESS_DB_PASSWORD (line 27)
• Update line 30: volumes: mariadb (to reflect the name used in line 9 for this volume)

While this example has mariadb enabled, you can switch to a mysql example by commenting out image: mariadb:10.7 and uncommenting #image: mysql:8.0.27.

Your updated file should look like this:

services:
  db:
    # We use a mariadb image which supports both amd64 & arm64 architecture
    image: mariadb:10.7
    # If you really want to use MySQL, uncomment the following line
    #image: mysql:8.0.27
    #command: '--default-authentication-plugin=mysql_native_password'
    volumes:
      - mariadb:/var/lib/mysql
    restart: always
    environment:
      - MYSQL_ROOT_PASSWORD=P@55W.RD123
      - MYSQL_DATABASE=wordpress
      - MYSQL_USER=wordpress
      - MYSQL_PASSWORD=P@55W.RD123
    expose:
      - 3306
      - 33060
  wordpress:
    image: wordpress:latest
    ports:
      - 80:80
    restart: always
    environment:
      - WORDPRESS_DB_HOST=db
      - WORDPRESS_DB_USER=wordpress
      - WORDPRESS_DB_PASSWORD=P@55W.RD123
      - WORDPRESS_DB_NAME=wordpress
volumes:
  mariadb:

Save these file changes and close your editor.

Running Docker Compose

Starting up Docker Compose is easy. To begin, ensure you’re in the wordpress-mysql folder and run the following from the Command Prompt:

docker compose up -d

This command kicks off the startup process. It downloads and soon runs your various container images from Docker Hub. Now, enter the following Docker command to confirm your containers are running as intended:

docker compose ps

This command should show all running containers and their active ports:

Verify that your WordPress app is active by navigating to http://localhost:80 in your browser — which should display the WordPress welcome page.

If you complete the required fields, it’ll redirect you to the WordPress dashboard, where you can start using WordPress. This experience is identical to running on a server or hosting environment.

Once testing is complete (or you’ve finished your daily development work), you can shut down your environment by entering the docker compose down command.

Reusing Your Environment

If you want to continue developing in this environment later, simply re-enter docker compose up -d. This action displays the development setup containing all of the previous information in the MySQL database. This takes just a few seconds.

However, what if you want to reuse the same environment with a fresh database?

To bring down the environment and remove the volume — which we defined within compose.yaml — run the following command:

docker compose down -v

Now, if you restart your environment with docker compose up, Docker Compose will summon a new WordPress instance. WordPress will have you configure your settings again, including the WordPress user, password, and website name:

While Awesome Compose sample projects work out of the box, always start with the README.md instructions file. You’ll typically need to update your sample YAML file with some environmental specifics — such as a password, username, or chosen database name. If you skip this step, the runtime won’t start correctly.

Awesome Compose Simplifies Multi-Container Management

Agile developers always need access to various application development-and-testing environments. Containers have been immensely helpful in providing this. However, more complex microservices architectures — which rely on containers running in tandem — are still quite challenging. Luckily, Docker Compose makes these management processes far more approachable.

Awesome Compose is Docker’s open-source library of sample workloads that empowers developers to quickly start using Docker Compose. The extensive library includes popular industry workloads such as ASP.NET, WordPress, and React web frontends. These can connect to MySQL, MariaDB, or MongoDB backends.

You can spin up samples from the Awesome Compose library in minutes. This lets you quickly deploy new environments locally or virtually. Our example also highlighted how easy customizing your Docker Compose YAML files and getting started are.

Now that you understand the basics of Awesome Compose, check out our other samples and explore how Docker Compose can streamline your next development project.

What is Docker Compose?

Docker Compose is a tool that helps you run multi-container applications. With Compose, you use a YAML file to configure your services. Here are some key benefits of Docker Compose:

• Simplified management of multiple environments through project names, which provide isolation
• Data-loss prevention, by automatically copying data from previous container runs to new ones
• Faster creation times, by only updating containers that have changed since the last run
• Easy app portability between environments using defined environment variables

You can read more deeply about these features on our Compose documentation page.

Use Cases

Docker Compose has use cases in development, testing, and single-host production environments:

• Development environments: Compose helps developers easily test their development environment by orchestrating the application in an isolated environment. This is achieved by specifying all application dependencies within the Compose file.
• Automated testing environments:  Like with development environments, Compose lets developers easily create isolated testing environments for their applications. This helps with shift-left testing, which is common to CI/CD. These isolated test environments are easily destructible once testing is finished.
• Single host deployments: Developers can re-use their Compose file — with some changes — in specific cases such as single-server deployments. This helps developers partially re-use their local development workflows in production.

We’ll focus on using Docker Compose to locally orchestrate and run your multi-container applications, to simplify testing. Docker Compose relies on Compose files to work effectively. So, how do you use them?

Using a Compose File

There are three main steps to using a Compose file:

1. Define your app environment with a Dockerfile so that it’s reproducible anywhere.
2. Define your app’s services within docker-compose.yml, so they can run together in an isolated environment.
3. Enter the docker compose up command. This starts and runs your entire app.

What is Awesome-Compose?

If you view a sample Compose file, it appears pretty simple for basic applications. However, it can quickly grow complex as you add more services to your application. To boost your productivity and get you started with Docker Compose, we maintain a GitHub repository called awesome-compose.

Awesome-compose is a curated collection of Docker Compose samples. These samples offer a starting point for services integration using a Compose file — and for managing their deployment with Docker Compose. They’re geared towards your local development environment and aren’t recommended for production workflows. However, awesome-compose provides you with a great starting blueprint, and is designed to save you development time and effort.

What does that look like in practice?  Let’s take a sample application and build a simple React app with a Spring backend and a MariaDB database. MariaDB is preferable over MySQL, since it’s compatible with AMD64 and ARM64 architecture.

Our Sample Application

Creating a Simple, non Container-Based Application

Let’s first create a sample “Hello from Docker” React application. To create a sample React application, type the following in your terminal:

npx create-react-app my-app

This creates a basic React application. You can now hop into your application folder and edit App.js to your liking. For the purposes of this guide, here’s a quick example:

function App() {

  return (
    <div className="App">
      <header className="App-header">
        <img src={logo} className="App-logo" alt="logo" />
        Hello from Docker 
        <a
          className="App-link"
          href="https://reactjs.org"
          target="_blank"
          rel="noopener noreferrer"
        >
          Learn React
        </a>
      </header>
    </div>
  );
}

After making any changes (in our case, choosing to print “Hello from Docker”), use the npm start command to view the React application. Here’s how that looks:

As you can see in the address bar, this application runs on port 3000.

Creating a Similar Multi-Container Application

Let’s say that you’re developing a similar application with a React frontend, a Spring (Java) backend, and a MariaDB database. This requires some additional steps. You’d want to use containers in this situation, because those containers package code and all dependencies into a single unit. This lets an application run quickly and reliably from one computing environment to another.

For simplicity’s sake, let’s say that this app needs one container for the frontend, one for the backend, and one for the database. This is a perfect opportunity for us to use react-java-mysql sample application from our awesome-compose GitHub project. As mentioned earlier in the blog,  MariaDB is preferable over MySQL, since it’s compatible with AMD64 and ARM64 architecture. However, you can use either by changing your DB image source in your Compose file. The process is as simple as changing a single line. 

To use awesome-compose, you’ll need to install Docker and Docker Compose on your machine. We also recommend installing Docker Desktop. This provides some added productivity benefits that you’ll soon learn more about.

The project structure of this sample application can be divided into the backend, frontend, database, and the Docker Compose file. The folder directory looks like this:

Similarly, the Docker Compose file (docker-compose.yaml) consists of three services:

• Backend
• Frontend
• DB

While examining the Compose file, you’ll see the following code:

frontend:
    build: frontend
    ports:
    - 3000:3000

Docker Compose is mapping port 3000 of the frontend-service container to host port 3000.

Deploying with Docker Compose

To deploy your sample application, navigate to the react-java-mysql file directory by using these two git commands: 

git clone https://github.com/docker/awesome-compose
cd react-java-mysql

If you want to download only react-java-mysql, enter the following commands:

git clone \
  --depth 1  \
  --filter=blob:none  \
  --sparse \
https://github.com/docker/awesome-compose \;

cd awesome-compose

git sparse-checkout set react-java-mysql 
cd react-java-mysql

The Docker Compose file is located within this folder. Next, enter the following into your terminal:

docker compose up -d

This jumpstarts multi-stage container deployment on your local machine. Since it’s the first time you’re running the containers, the process may take a few moments. Thankfully, only changed containers will update the next time you run this application. The rest is cached, dramatically shortening the testing phase between changes. Once you’ve finished, you should see a terminal output similar to this:

It’s important to enter docker compose instead of docker-compose. We’re using Docker Compose V2 to build the application, which has introduced some basic syntax changes. You can read more about this transition in our documentation.

Want to see what’s currently active? You can summon a list of running containers with the docker ps command. This outputs the following:

Visualizing your containers is even easier within Docker Desktop, via the Dashboard:

The Docker Dashboard doesn’t only display running containers belonging to your multi-container Compose application. It also lets you easily start, pause, stop, or delete any container. Additionally, Docker Desktop lets you manage a particular container via CLI commands.

From the Docker Dashboard, you can click the “Open in Browser” button to open the localhost. You can alternatively navigate to it directly within your browser.

Since your application is running on port 3000, you’ll see the following:

To stop or delete the application, you can use the Docker Desktop interface shown below:

Finally, you can always use the docker compose down command to achieve the same result.

Key Takeaways

Congratulations! You now know the basics of using Docker Compose and the awesome-compose Github repository. Both tools can also accommodate deployments that are more complex — as shown while running a multi-container application from the awesome-compose repository.

The awesome-compose repository is created to give you an easy starting point for building your multi-container applications. You also learn how you can visualize and control your multi-container applications in the local development environment using Docker Desktop.

You can also contribute to the awesome-compose library! If you’re interested in helping our community better leverage Docker Compose, please follow our Contribution Guide. You’ll receive assistance with making your pull requests and getting those sample applications live.

Join us for DockerCon 2022!

Want to learn more about cloud-native development, and how Docker’s tools can help? Join us at DockerCon2022 on Tuesday, May 10. 

DockerCon is a free, one-day virtual event geared towards developers and development teams who are building the next generation of modern applications. We invite you to come discover more, learn more, excel within your role, and connect with thousands of your fellow tech community members. DockerCon is right around the corner, so register today!