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Windows 10 Docker Image On Linux

  • Docker is a platform for running applications in lightweight units of compute called containers. You can take pretty much any app and run it in a container, and this course will teach you how to do that - with 100% focus on.NET applications and real-world skills. You'll learn how to run.NET Framework applications in Windows containers,.
  • After a better understanding of how Docker was interacting with WSL and figuring that WSL was likely hiding much of it’s Linux file data internally somewhere I opened a WSL shell and started exploring Location of docker image data under WSL. This was all a bit tricky in that you won’t find these images in a host Windows 10 search.

March 2, 2020 by Matt Hernandez, @fiveisprime

Last June, the Docker team announced that they will be investing in getting Docker running with the Windows Subsystem for Linux (WSL). All of this is made possible with the recent changes to the architecture of WSL to run within a lightweight virtual machine (VM), which we talked about in an earlier blog post about WSL 2. Since this announcement, the Docker team has released a Technical Preview of Docker that includes support for running with WSL 2.

UPDATE: LCOW support is available in Windows 10 Fall Creators Update and in Windows Server 1709. The simplest way to try it out on Windows 10 is to install the edge variant of Docker for Windows. On Windows Server 1709, install EE preview. Running Docker Linux Containers on Windows with LinuxKit. EasyWSL is a tool that converts Linux Docker images to a Windows 10 WSL distribution Check all news and articles from the latest Security news updates. Disclaimer: If you need to update/edit this article then please visit our help center.

This article explains how the Docker Desktop technical preview works as well as how to use the Docker extension with the technical preview.

How it works

This new Docker architecture works a lot like Visual Studio Code's WSL remote development support in that the Docker CLI running on the host machine executes commands within the Docker Integration Package, which runs on the remote WSL VM.

Image credit: Docker Engineering

DockerD runs directly within WSL so there's no need for the Hyper-V VM and all Linux containers run within the Linux userspace on Windows for improved performance and compatibility.

Windows 10 Docker Image On Linux

Getting set up

First some prerequisites:

  • Install Windows 10 Insider Preview build 18975 (Slow) or later for WSL 2.
  • Install Ubuntu from the Microsoft store.
  • Enable WSL 2 by following this guide.
  • Install the Remote - WSL extension for VS Code.
  • Install the Docker WSL 2 Technical Preview.
Docker

Once installed, Docker will recognize that you have WSL installed and prompt to enable WSL integration. You want to Enable WSL integration for this tutorial.

This option will allow you to access Docker Desktop via the Docker CLI directly from within your Linux distro.

If you have multiple Linux distros, make sure you only have WSL integration turned on for the correct one in your Docker settings:

With that configured, all commands will execute in the Linux context - this includes Docker commands run from PowerShell so running something like docker run mongo… will start a Linux container within the WSL VM.

Running the docker ps command over in WSL, you'll see the container as expected. Notice that the container ID matches.

Using VS Code

With this set up and running, you can install the VS Code Docker extension and access your containers. If you're already running WSL 2 and the Remote - WSL extension, this will help you get Docker integrated into your WSL workflow rather than switching contexts when you need containers. And because the Docker CLI's context is set to use DockerD in WSL, the extension will work with your containers regardless of whether you opened VS Code using the Remote - WSL extension.

Notice how in the screenshot below, I'm connected and working in WSL and still building/running containers without changing from my preferred environment (zsh in Ubuntu).

Theme: Noctis Sereno

I've personally noticed a vast improvement in container execution times using this configuration and each part of my typical development workflow remains the same. I'm also using the Remote - Containers extension within WSL for testing specific environments without setting things up directly on my machine.

We want your feedback

Keep in mind that you're using prerelease software and, while the Windows Insiders Slow ring is very stable, you may run into some issues. If you do find something that isn't working as expected, please open an issue via the Feedback tool in Windows. Any direct Docker issues or feedback can be logged in the Docker for Windows repo.

Happy Coding!

Matt Hernandez, VS Code Program Manager @fiveisprime

Linux Development in Windows 10 with Docker and WSL 2

I’m first and foremost a Windows guy. But for a few years now, moving away from working mostly with .NET and into a plethora of open source technologies has given me the opportunity to change platforms and run a Linux-based system as my daily driver. Ubuntu, which I honestly love for work, has been serving me well by supporting my development workflow with languages like PHP, JavaScript and Ruby. And with the help of the excellent Visual Studio Code editor, I’ve never looked back. There’s always been an inclination in the back of my mind though, to take some time and give Windows another shot.

With the latest improvements coming to the Windows Subsystem for Linux with its second version, the new and exciting Windows Terminal, and Docker support for running containers inside WSL2, I think the time is now.

Windows 10 Docker Image On LinuxDocker

In this post, we’ll walk through the steps I took to set up a PHP development environment in Windows, running in a Ubuntu Docker container running on WSL 2, and VS Code. Let’s go.

Note: You have to be on the latest version of Windows 10 Pro (Version 2004) in order to install WSL 2 by the usual methods. If not, you’d need to be part of the Windows Insider Program to have access to the software.

What’s new with WSL 2

This is best explained by the official documentation. However, being a WSL 1 veteran, I’ll mention a few improvements made which have sparked my interest in trying it again.

1. It’s faster and more compatible

WSL 2 introduces a complete architectural overhaul. Now, Windows ships with a full Linux Kernel which WSL 2 distributions run on. This results in greatly improved file system performance and much better compatibility with Linux programs. It’s no longer running a Linux look-alike, but actual Linux.

2. It’s better integrated with Windows

This is a small one: we can now use the Windows explorer to browse files within a WSL distribution. This is not a WSL 2 exclusive feature, it has been there for a while now. I think it’s worth mentioning though, because it truly is a great convenience and a far cry from WSL’s first release, where Microsoft specifically advised against manipulating WSL distribution file systems from Windows. If nothing else, this makes WSL feel like a first class citizen in the Windows ecosystem and shows that Microsoft actually cares about making it a good experience.

3. It can run Docker

I’ve recently been learning more and more about Docker and it’s quickly becoming my preferred way of setting up development environments. Due to its lightweightness, ease of use, repeatability, and VM-like compartmentalization, I find it really convenient to develop against a purpose-built Docker container, rather than directly in my local machine. And with VS Code’s Remote development extension, the whole thing is very easy to set up. Docker for Windows now supports running containers within WSL, so I’m eager to try that out and see how it all works.

4. A newer version means several bugfixes

Windows 10 Docker Image On Linux

Performance notwithstanding, WSL’s first release was pretty stable. I did, however, encounter some weird bugs and gotchas when working with the likes of SSH and Ruby during certain tasks. It was nothing major, as workarounds were readily available. I’ve already discussed some of them here, so I won’t bother mentioning them here again. But thanks to the fact that the technology has matured since last time I saw it, and considering the architectural direction it is going in, I’m excited to not have to deal with any number of quirks.

The development environment

Ok, now with some of the motivation out of the way, let’s try and build a quick PHP Hello World app running in a Docker container inside WSL 2, make sure we can edit and debug it with VS Code, and access it in a browser from Windows.

Step 1: Install WSL 2 and Ubuntu

Step 1 is obviously to install WSL and a Linux distribution that we like. Microsoft’s own documentation offers an excellent guide on how to do just that. But in summary, we need to:

  1. Enable the “Windows Subsystem for Linux” and “Virtual Machine Platform” features by running these on an elevated PowerShell:
  1. Restart your machine.
  2. Set WSL 2 as the default version with: wsl --set-default-version 2, also from PowerShell.
  3. Install your desired distribution from the Microsoft Store. I chose Ubuntu 20.04 LTS.
  4. After installing, open the “Ubuntu 20.04 LTS” app from the Start menu and it should come up with a command line console. Wait for it to finish installing. It should prompt for a username and password along the way. Choose something you won’t forget.

Optionally, you can install the Windows Terminal app to get a better command line experience. Windows Terminal can be used to interact with PowerShell and the classic CMD, as well as with our WSL distributions.

Step 2: Install Docker

Installing Docker is very straightforward. Just download the installer for Docker Desktop for Windows, execute it, and follow the wizard’s steps. Make sure that during setup the “Use the WSL 2 based engine” option is selected. In most cases, the installer will detect WSL 2 and automatically have the option selected.

Follow the official instructions for more details on the process, but it really is that simple.

Build Linux Docker Image On Windows 10

Step 3: Install some useful VS Code extensions

Our objective is to create a new development environment inside a Docker container and connect to it directly with VS Code. To do that, we use a few useful extensions:

  1. The Docker extension which allows us to browse and manage images and containers and other types of Docker assets.
  2. The Remote - WSL extension which allows VS Code to connect to a WSL distribution.
  3. The Remote - Containers extension which allows VS Code to connect to a container.

Step 4: Create the development container

The extensions that we installed will allow us to use VS Code to work on code from within our WSL Ubuntu as well as from the container. Specifically, we want to connect VS Code to a container. There are a few ways to do this, but I will describe the one I think is the easiest, most convenient and “automagic” by fully leveraging the tools.

Let’s begin by opening a WSL Ubuntu terminal session, which will show something like this:

The project directory

Let’s change to our home, create a new directory for our new project, and change into it.

Because we installed the Remote - WSL extension, we can open up this directory in VS Code with code .. Opening a terminal (Ctrl + `) in this VS Code instance opens WSL console, not Windows.

The Dockerfile

Now let’s create a new file called Dockerfile which will define what our development environment image will look like. For a no-frills PHP environment, mine looks like this:

This script will later be used to create our development container. It will have PHP, Xdebug and Composer. This is all we need for our simple Hello World app. For more complex scenarios, other software like database clients or PHP extensions can be easily installed with additional RUN statements that call upon the apt package manager.

Consider reading through Docker’s official documentation on Dockerfiles to learn more.

The configuration file

Now, to leverage VS Code’s capabilities, let’s add a development container configuration file. In our current location, we need to create a new directory called .devcontainer and, inside that, a new file called devcontainer.json. I put these contents in mine:

A default version of this file can be automatically generated by running the “Remote-Containers: Add Development Container Configuration Files…” command in VS Code’s Command Palette (Ctrl + Shift + P).

The development container

Now that we have all that in place, we can create our image, run our container, and start coding our app. Bring up the VS Code Command Palette with Ctrl + Shift + P and run the “Remote-Containers: Reopen in Container” command. The command will:

  1. Read the Dockerfile and create an image based on that. This is like running docker build -t AUTOGENERATED_IMAGE_ID .
  2. Run a container based on that image with the settings specified in .devcontainer/devcontainer.json. In our case, all it will do is enable the container’s port 5000 to be accessible by the host. This is more or less like running: docker run -d -p 5000:5000 -v ${PWD}:/workspaces/php-in-docker-demo AUTOGENERATED_IMAGE_ID
  3. Open a new VS Code instance connected to the container with the /workspaces/php-in-docker-demo directory open.

It will take a while, but after it’s done, we will have a VS Code instance running directly in the container. Open the VS Code terminal with Ctrl + ` and see for yourself. It will show a prompt looking like this:

Windows 10 Docker Image On Linux Download

You can for example, run php -v in this terminal, and expect something along these lines:

This is PHP running, not in Windows, not in our WSL Ubuntu, but in the Docker container.

Hello Windows + WSL 2 + Ubuntu + Docker + PHP + VS Code

Let’s now create our app. Add a new index.php file containing something silly like:

Then, in the VS Code console (remember, Ctrl + `), start up an instance of the built in PHP development server wth php -S 0.0.0.0:5000. It’s important that we use port 5000 because that’s the one that we configured our container to use.

Navigate to http://localhost:5000/ in your browser and feel good about a job well done.

Interactive debugging

When configuring our development container, we added Xdebug and the PHP Debug VS Code extension. This means that VS Code can leverage Xdebug to provide an interactive debugging experience for PHP code.

Almost everyting is set up at this point, we just need to do the usual VS Code configuration and add a launch.json file. To do so, in VS Code, press Ctrl + Shift + D to bring up the “Run” panel, click on the “create a launch.json file” link, and in the resulting “Select Environment” menu, select “PHP”.

After that, the “Run” panel will show a green triangular “Start Debugging” button next to a “Listen to XDebug” text. If you haven’t already, start up a dev web server with php -S 0.0.0.0:5000, click on the “Start Debugging” button, put a breakpoint somewhere in your index.php file, and finally open up http://localhost:5000/ in a browser.

We’re interactively debugging PHP code running on a Docker container in WSL from our Windows IDE/​editor. Pretty cool, huh?

And that’s all for now. In this article we’ve learned how to set up a Linux development environment using Docker containers and WSL 2, with Windows 10 Pro. This is a nice approach for anybody who’s confortable on Windows and needs access to a Linux environment for development; and have that environment be easy to reproduce.

Resources:

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