Example: Develop Linux applications in a container machine with Visual Studio Code

This example shows you how to use a container machine to develop for Linux on your Mac using Visual Studio Code and its SSH remote development extension.

Prerequisites

Install and start before running the demo:

• Apple container
• Microsoft Visual Studio Code, including the Visual Studio Code Remote - SSH extension

Container machine overview

The container machine subcommand allows you to run fast, persistent Linux environments that integrate tightly with your macOS host.

To create a container machine, all you need to do is provide a machine name, and a machine image reference:

% container machine create --name mymachine --set-default alpine:3.22
mymachine

Display a list of container machines with:

% container machine ls
NAME       CREATED              IP             CPUS  MEMORY  DISK  STATE    DEFAULT
mymachine  2026-06-03 15:56:14  192.168.71.15  8     64G     75M   running  *

Run individual Linux commands with container machine run and the command:

% container machine run uname -a
Linux mymachine-dce75a 6.18.15-cz-325d33a88139 #1 SMP Mon Apr 20 22:39:49 UTC 2026 aarch64 Linux

Display your macOS working directory and username, start a shell session in the container machine, and compare the working directory and username in the container machine:

% pwd
/Users/max-mustermann/projects/container/examples/container-machine-vscode
% whoami
john
% container machine run
$ pwd
/Users/max-mustermann/projects/container/examples/container-machine-vscode
$ whoami
john
$ exit
%

Typically, you'll keep container machines for longer than a typical container. When you're ready to delete a container machine and its persistent filesystem, run:

% container machine stop mymachine
mymachine
% container machine rm mymachine
mymachine
Deleted default container 'mymachine'. Set a new default with 'container machine set-default <id>'.

Develop in a container machine

SSH and DNS setup

On your Mac, add an SSH configuration entry for the container machine, so that it will appear as an option when you connect to the container machine with Visual Studio Code later:

cat >> ~/.ssh/config <<EOT

Host ubuntu.machine
   HostName ubuntu.machine
   ForwardAgent yes
   UserKnownHostsFile /dev/null
EOT

Add a locally scoped domain named machine to your macOS DNS configuration:

sudo container system dns create machine

Build the machine image

On your Mac:

container build -t ubuntu-machine:latest -f Dockerfile .

Container machine setup

On your Mac, create a container machine named ubuntu using the image you built:

container machine create --set-default --name ubuntu ubuntu-machine:latest

Set up a password for SSH login to the container machine:

container machine run -it sudo passwd $(whoami)

You can ping the container machine to see that DNS is working:

ping -c 1 ubuntu.machine

You can also start a shell in the machine to run ad-hoc commands:

container machine run

Set up the project

On your Mac, clone the swift-server-todos-tutorial project:

cd ${HOME}
git clone git@github.com:swiftlang/swift-server-todos-tutorial.git

In the Visual Studio Code application, connect to the container machine and install the Swift extension:

• Press ⌘-SHIFT-P and run the Remote-SSH: Connect to Host command
• Select the ubuntu.machine entry
• In the new Visual Studio Code window that opens, enter yes at the ssh fingerprint verification prompt
• Enter the SSH password you configured at the authentication prompt
• In the extensions sidebar of the new Visual Studio Code window, install the Swift (swiftlang.swift-vscode) extension

Build and run

In the new Visual Studio Code window, open the project folder (substituting your macOS username) at /Users/max-mustermann/swift-server-todos-tutorial.

Restart the LSP server in response to the toast notification that appears.

Open the LSP build terminal output window and watch its progress. This takes a couple of minutes for a totally clean project.

Open another terminal in the Visual Studio Code window to get a shell, and verify that you're running on an Ubuntu Linux system:

uname -s
cat /etc/os-release | grep PRETTY_NAME

Build the project:

swift build

While the project builds, press ⌘-SHIFT-P and run the Open 'launch.json' command.

Click the Add configuration... button and select the Swift: Launch option.

Replace the <program> placeholder in the newly added launch configuration, so that it looks like:

        {
            "type": "swift",
            "request": "launch",
            "name": "Launch Swift Executable",
            "program": "${workspaceRoot}/.build/debug/SwiftServerTodos",
            "args": [],
            "env": {},
            "cwd": "${workspaceRoot}"
        },

Run the application by selecting the Run and Debug sidebar, selecting the Launch Swift Executable item, and clicking the play button.

Open the Telemetry.swift file and set a breakpoint on the innermost statement of the RequestLoggerInjectionMiddleware.respond() function.

From a terminal on your Mac, try a request to the service:

curl http://ubuntu.machine:8080/todos

Observe that the application hits the breakpoint and that you can inspect the request, and then remove the breakpoint and continue execution.

On the terminal, you should see output similar to:

[{"id":"BDAD25BA-8F52-4A7A-B98D-319AD86179B7","contents":"example todo"}]

Clean up

When you're ready to dispose of your container machine, run on your Mac:

container machine stop ubuntu
container machine rm ubuntu
container image rm ubuntu-machine:latest

Then remove the test project:

rm -rf swift-server-todos-tutorial

To remove the entry from your SSH configuration file, run:

awk -v h="ubuntu.machine" '/^Host /{skip=($2==h)} !skip' ~/.ssh/config > /tmp/.sshconf && mv /tmp/.sshconf ~/.ssh/config

To clean up the local DNS entry, run:

sudo container system dns delete machine