Windows Docker Run Linux Container

Does docker windows containers, with Docker Desktop for Windows, have default memory limit? I have an application that was crashing when I run it in the container, but when I tried to specify -memory 2048mb parameter to the docker run command it seems to run fine. At least in the scenario where it was crashing before. With Docker for Windows started and Windows containers selected, you can now run either Windows or Linux Containers simultaneously. The new –platform=linux command line switch is used to pull or start Linux images on Windows. Docker pull -platform=linux ubuntu. Now start the Linux container and a Windows Server Core container.

The result is that Docker created a container from the 'HelloWorld' image, Docker started an instance of cmd.exe in the container, and the cmd.exe read our file and output the contents to the shell. As the final step, Docker stopped and removed the container. Run a Windows container using Windows Admin Center. Build and Run Your First Windows Server Container (Blog Post) gives a quick tour of how to build and run native Docker Windows containers on Windows 10 and Windows Server 2016 evaluation releases. Getting Started with Windows Containers (Lab) shows you how to use the MusicStore application with Windows containers. Docker Desktop networking can work when attached to a VPN. To do this, Docker Desktop intercepts traffic from the containers and injects it into Windows as if it originated from the Docker application. When you run a container with the -p argument, for example.

-->

This step-by-step guide will help you get started developing with remote containers by setting up Docker Desktop for Windows with WSL 2 (Windows Subsystem for Linux, version 2).

Docker Desktop for Windows is available for free and provides a development environment for building, shipping, and running dockerized apps. By enabling the WSL 2 based engine, you can run both Linux and Windows containers in Docker Desktop on the same machine.

Overview of Docker containers

Docker is a tool used to create, deploy, and run applications using containers. Containers enable developers to package an app with all of the parts it needs (libraries, frameworks, dependencies, etc) and ship it all out as one package. Using a container ensures that the app will run the same regardless of any customized settings or previously installed libraries on the computer running it that could differ from the machine that was used to write and test the app's code. This permits developers to focus on writing code without worrying about the system that code will be run on.

Docker containers are similar to virtual machines, but don't create an entire virtual operating system. Instead, Docker enables the app to use the same Linux kernel as the system that it's running on. This allows the app package to only require parts not already on the host computer, reducing the package size and improving performance.

Continuous availability, using Docker containers with tools like Kubernetes, is another reason for the popularity of containers. This enables multiple versions of your app container to be created at different times. Rather than needing to take down an entire system for updates or maintenance, each container (and it's specific microservices) can be replaced on the fly. You can prepare a new container with all of your updates, set up the container for production, and just point to the new container once it's ready. You can also archive different versions of your app using containers and keep them running as a safety fallback if needed.

Install mojave link. To learn more, checkout the Introduction to Docker containers on Microsoft Learn.

Prerequisites

Ensure your machine is running Windows 10, updated to version 2004, Build 18362 or higher.
Enable WSL, install a Linux distribution, and update to WSL 2.
Download and install the Linux kernel update package.
Install Visual Studio Code(optional). This will provide the best experience, including the ability to code and debug inside a remote Docker container and connected to your Linux distribution.
Install Windows Terminal(optional). This will provide the best experience, including the ability to customize and open multiple terminals in the same interface (including Ubuntu, Debian, PowerShell, Azure CLI, or whatever you prefer to use).
Sign up for a Docker ID at Docker Hub(optional).

Note

WSL can run distributions in both WSL version 1 or WSL 2 mode. You can check this by opening PowerShell and entering: wsl -l -v. Ensure that the your distribution is set to use WSL 2 by entering: wsl --set-version <distro> 2. Replace <distro> with the distro name (e.g. Ubuntu 18.04).

In WSL version 1, due to fundamental differences between Windows and Linux, the Docker Engine couldn't run directly inside WSL, so the Docker team developed an alternative solution using Hyper-V VMs and LinuxKit. However, since WSL 2 now runs on a Linux kernel with full system call capacity, Docker can fully run in WSL 2. This means that Linux containers can run natively without emulation, resulting in better performance and interoperability between your Windows and Linux tools.

Install Docker Desktop

With the WSL 2 backend supported in Docker Desktop for Windows, you can work in a Linux-based development environment and build Linux-based containers, while using Visual Studio Code for code editing and debugging, and running your container in the Microsoft Edge browser on Windows.

To install Docker (after already installing WSL 2):

Download Docker Desktop and follow the installation instructions.
Once installed, start Docker Desktop from the Windows Start menu, then select the Docker icon from the hidden icons menu of your taskbar. Right-click the icon to display the Docker commands menu and select 'Settings'.
Ensure that 'Use the WSL 2 based engine' is checked in Settings > General.
Select from your installed WSL 2 distributions which you want to enable Docker integration on by going to: Settings > Resources > WSL Integration.
To confirm that Docker has been installed, open a WSL distribution (e.g. Ubuntu) and display the version and build number by entering: docker --version
Test that your installation works correctly by running a simple built-in Docker image using: docker run hello-world

Tip

Here are a few helpful Docker commands to know:

List the commands available in the Docker CLI by entering: docker
List information for a specific command with: docker <COMMAND> --help
List the docker images on your machine (which is just the hello-world image at this point), with: docker image ls --all
List the containers on your machine, with: docker container ls --all or docker ps -a (without the -a show all flag, only running containers will be displayed)
List system-wide information regarding the Docker installation, including statistics and resources (CPU & memory) available to you in the WSL 2 context, with: docker info

Develop in remote containers using VS Code

To get started developing apps using Docker with WSL 2, we recommend using VS Code, along with the Remote-WSL extension and Docker extension.

Install the VS Code Remote-WSL extension. This extension enables you to open your Linux project running on WSL in VS Code (no need to worry about pathing issues, binary compatibility, or other cross-OS challenges).
Install the VS code Remote-Containers extension. This extension enables you to open your project folder or repo inside of a container, taking advantage of Visual Studio Code's full feature set to do your development work within the container.
Install the VS Code Docker extension. This extension adds the functionality to build, manage, and deploy containerized applications from inside VS Code. (You need the Remote-Container extension to actually use the container as your dev environment.)

Can Windows Docker Run Linux Containers

Let's use Docker to create a development container for an existing app project.

For this example, I'll use the source code from my Hello World tutorial for Django in the Python development environment set up docs. You can skip this step if you prefer to use your own project source code. To download my HelloWorld-Django web app from GitHub, open a WSL terminal (Ubuntu for example) and enter: git clone https://github.com/mattwojo/helloworld-django.git
Note
Always store your code in the same file system that you're using tools in. This will result in faster file access performance. In this example, we are using a Linux distro (Ubuntu) and want to store our project files on the WSL file system wsl. Storing project files on the Windows file system would significantly slow things down when using Linux tools in WSL to access those files.
From your WSL terminal, change directories to the source code folder for this project:
Open the project in VS Code running on the local Remote-WSL extension server by entering:
Confirm that you are connected to your WSL Linux distro by checking the green remote indicator in the bottom-left corner of your VS Code instance.
From the VS Code command pallette (Ctrl + Shift + P), enter: Remote-Containers: Open Folder in Container.. If this command doesn't display as you begin to type it, check to ensure that you've installed the Remote Container extension linked above.
Select the project folder that you wish to containerize. In my case, this is wslUbuntu-20.04homemattwojoreposhelloworld-django
A list of container definitions will appear, since there is no DevContainer configuration in the project folder (repo) yet. The list of container configuration definitions that appears is filtered based on your project type. For my Django project, I'll select Python 3.
A new instance of VS Code will open, begin building our new image, and once the build completed, will start our container. You will see that a new .devcontainer folder has appeared with container configuration information inside a Dockerfile and devcontainer.json file.
To confirm that your project is still connected to both WSL and within a container, open the VS Code integrated terminal (Ctrl + Shift + ~). Check the operating system by entering: uname and the Python version with: python3 --version. You can see that the uname came back as 'Linux', so you are still connected to the WSL 2 engine, and Python version number will be based on the container config that may differ from the Python version installed on your WSL distribution. Claw game for mac.
To run and debug your app inside of the container using Visual Studio Code, first open the Run menu (Ctrl+Shift+D or select the tab on the far left menu bar). Then select Run and Debug to select a debug configuration and choose the configuration that best suites your project (in my example, this will be 'Django'). This will create a launch.json file in the .vscode folder of your project with instructions on how to run your app.
From inside VS Code, select Run > Start debugging (or just press the F5 key). This will open a terminal inside VS Code and you should see a result saying something like: 'Starting development server at http://127.0.0.1:8000/ Quit the server with CONTROL-C.' Hold down the Control key and select the address displayed to open your app in your default web browser and see your project running inside of its container.

You have now successfully configured a remote development container using Docker Desktop, powered by the WSL 2 backend, that you can code in, build, run, deploy, or debug using VS Code!

Troubleshooting

WSL docker context deprecated

If you were using an early Tech Preview of Docker for WSL, you may have a Docker context called 'wsl' that is now deprecated and no longer used. You can check with the command: docker context ls. You can remove this 'wsl' context to avoid errors with the command: docker context rm wsl as you want to use the default context for both Windows and WSL2.

Possible errors you might encounter with this deprecated wsl context include: docker wsl open //./pipe/docker_wsl: The system cannot find the file specified. or error during connect: Get http://%2F%2F.%2Fpipe%2Fdocker_wsl/v1.40/images/json?all=1: open //./pipe/docker_wsl: The system cannot find the file specified.

For more on this issue, see How to set up Docker within Windows System for Linux (WSL2) on Windows 10.

Trouble finding docker image storage folder

Docker creates two distro folders to store data:

wsl$docker-desktop
wsl$docker-desktop-data

You can find these folders by opening your WSL Linux distribution and entering: explorer.exe . to view the folder in Windows File Explorer. Enter: wsl<distro name>mntwsl replacing <distro name> with the name of your distribution (ie. Ubuntu-20.04) to see these folders.

Find more on locating docker storage locations in WSL, see this issue from the WSL repo or this StackOverlow post.

For more help with general troubleshooting issues in WSL, see the Troubleshooting doc.

Additional resources

-->

This topic describes how to run your first Windows container, after setting up your environment as described in Get started: Prep Windows for containers. To run a container, you first install a base image, which provides a foundational layer of operating system services to your container. Then you create and run a container image, which is based upon the base image. For details, read on.

Install a container base image

All containers are created from container images. Microsoft offers several starter images, called base images, to choose from (for more details, see Container base images). This procedures pulls (downloads and installs) the lightweight Nano Server base image.

Open a command prompt window (such as the built-in command prompt, PowerShell, or Windows Terminal), and then run the following command to download and install the base image:
Tip
If you see an error message that says no matching manifest for unknown in the manifest list entries, make sure Docker isn't configured to run Linux containers.
After the image is finished downloading—read the EULA while you wait—verify its existence on your system by querying your local docker image repository. Running the command docker images returns a list of installed images.
Here's an example of the output showing the Nano Server image.

Run a Windows container

Docker Run Windows And Linux Containers In Parallel

For this simple example, a ‘Hello World’ container image will be created and deployed. For the best experience, run these commands in an elevated command prompt window (but don't use the Windows PowerShell ISE—it doesn't work for interactive sessions with containers, as the containers appear to hang).

Start a container with an interactive session from the nanoserver image by entering the following command in your command prompt window:
After the container is started, the command prompt window changes context to the container. Inside the container, we'll create a simple ‘Hello World’ text file and then exit the container by entering the following commands:
Get the container ID for the container you just exited by running the docker ps command:
Create a new ‘HelloWorld’ image that includes the changes in the first container you ran. To do so, run the docker commit command, replacing <containerid> with the ID of your container:
When completed, you now have a custom image that contains the hello world script. This can be seen with the docker images command.
Here's an example of the output:
Finally, run the new container by using the docker run command with the --rm parameter that automatically removes the container once the command line (cmd.exe) stops.
The result is that Docker created a container from the 'HelloWorld' image, Docker started an instance of cmd.exe in the container, and the cmd.exe read our file and output the contents to the shell. As the final step, Docker stopped and removed the container.

Run a Windows container using Windows Admin Center

Windows Admin Center can be used to run your containers locally. Specifically, you use the the Containers extension of your Windows Admin Center instance to run the containers. First, open the container host you want to manage, and in the Tools pane, select the Containers extension. Then, select the Images tab inside the Container extension under Container Host.

If your host doesn't have a base container image, select the Pull option which opens the following:

In the Pull Container Image settings, provide the image URL and the tag. If you aren't certain which image to pull, Windows Admin Center provides a list of common images from Microsoft. You can also provide the credentials to pull an image from a private repository. Once you fill out the necessary information, click Pull. Windows Admin Center will start the pull process on the container host. After the download is complete, you should see the new image on the Images tab.

Select the image you want to run, and click Run.