mirror of https://github.com/docker/docs.git
117 lines
4.8 KiB
Markdown
117 lines
4.8 KiB
Markdown
---
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title: Run multi-container applications
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keywords: get started, quick start, intro, concepts
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description: Learn how to use Docker to run multi-container applications
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---
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If you've already completed the [How do I run a container?](./run-a-container.md) walkthrough, you learned that you must start each container individually. Imagine how great it would be if a tool could start multiple containers with a single command. That tool is Docker Compose.
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{{< include "guides-get-docker.md" >}}
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## Step 1: Get the sample application
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If you have git, you can clone the repository for the sample application. Otherwise, you can download the sample application. Choose one of the following options.
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{{< tabs >}}
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{{< tab name="Clone with git" >}}
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Use the following command in a terminal to clone the sample application repository.
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```console
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$ git clone https://github.com/docker/multi-container-app
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```
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{{< /tab >}}
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{{< tab name="Download" >}}
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Download the source and extract it.
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{{< button url="https://github.com/docker/multi-container-app/archive/refs/heads/main.zip" text="Download the source" >}}
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{{< /tab >}}
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{{< /tabs >}}
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The sample application is a simple todo application built using ExpressJS and Node.js. The application saves all todos in a MongoDB database. You don't need to know any of these technologies to continue with the walkthrough.
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## Step 2: Dig into the Compose file
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View the files of the sample application. Notice that it has a `compose.yaml` file. This file tells Docker how to run your application. Open the `compose.yaml` file in a code or text editor to view what it contains.
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## Step 3: Run the application
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To run the multi-container application, open a terminal and run the following commands. Replace `/path/to/multi-container-app/` with the path to your application's directory.
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{{< include "open-terminal.md" >}}
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```console
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$ cd /path/to/multi-container-app/
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```
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```console
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$ docker compose up -d
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```
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In the previous command, the `-d` flag tells Docker Compose to run in detached mode.
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## Step 4: View the frontend and add todos
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In the **Containers** tab of Docker Desktop, you should now have an application stack with two containers running (the todo-app, and todo-database).
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To view the frontend:
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1. In Docker Desktop, expand the application stack in **Containers**.
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2. Select the link to port **3000** in the **Port(s)** column or open [http://localhost:3000](http://localhost:3000).
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Add some todo tasks in the frontend, and then open [http://localhost:3000](http://localhost:3000) in a new browser tab. Notice that the tasks are still visible.
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## Step 5: Develop in your containers
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When developing with Docker, you may need to automatically update and preview your running services as you edit and save your code. You can use Docker Compose Watch for this.
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To run Compose Watch and see the real-time changes:
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1. Open a terminal and run the following commands. Replace `/path/to/multi-container-app/` with the path to your application's directory.
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```console
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$ cd /path/to/multi-container-app/
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```
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```console
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$ docker compose watch
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```
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2. Open `app/views/todos.ejs` in a text or code editor, then change the text on line 18.
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3. Save the changes in `app/views/todos.ejs`.
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4. View your application at [http://localhost:3000](http://localhost:3000) to see the changes in real-time.
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## Step 6: Delete everything and start over
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Having your configuration stored in a Compose file has another advantage, you can easily delete everything and start over.
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To delete the application stack:
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1. Open the **Containers** tab of Docker Desktop
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2. Select the Delete icon next to your application stack.
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After you delete the application stack, follow the steps from [Step 3: Run the
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application](#step-3-run-the-application) to run the application again. Note
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that when you delete the containers and run them again, any todos that you
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created don't persist.
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## Summary
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In this walkthrough, you ran a multi-container application with Docker Compose. You also learned how to develop in containers and how to delete the application stack along with all of the data.
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Related information:
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- Deep dive into the [Docker Compose manual](../../compose/_index.md)
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- Reference Compose commands in the [Docker Compose CLI reference](../../compose/reference/_index.md)
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- Explore samples in the [Awesome Compose GitHub repository](https://github.com/docker/awesome-compose)
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- Learn how to implement Compose Watch for your projects in [Use Compose Watch](../../compose/file-watch.md)
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## Next steps
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Continue to the next walkthrough to learn how to persist data even after deleting the application stack.
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{{< button url="./persist-data.md" text="Persist container data" >}}
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