headscale/docs/running-headscale-container.md

Running headscale in a container

Note: the container documentation is maintained by the community and there is no guarentee it is up to date, or working.

Goal

This documentation has the goal of showing a user how-to set up and run headscale in a container. Docker is used as the reference container implementation, but there is no reason that it should not work with alternatives like Podman. The Docker image can be found on Docker Hub here.

Configure and run headscale

1. Prepare a directory on the host Docker node in your directory of choice, used to hold headscale configuration and the SQLite database:

mkdir -p ./headscale/config
cd ./headscale

2. Create an empty SQlite datebase in the headscale directory:

touch ./config/db.sqlite

3. (Strongly Recommended) Download a copy of the example configuration from the headscale repository.

Using wget:

wget -O ./config/config.yaml https://raw.githubusercontent.com/juanfont/headscale/main/config-example.yaml

Using curl:

curl https://raw.githubusercontent.com/juanfont/headscale/main/config-example.yaml -o ./config/config.yaml

(Advanced) If you would like to hand craft a config file instead of downloading the example config file, create a blank headscale configuration in the headscale directory to edit:

touch ./config/config.yaml

Modify the config file to your preferences before launching Docker container. Here are some settings that you likely want:

server_url: http://your-host-name:8080 # Change to your hostname or host IP
metrics_listen_addr: 0.0.0.0:9090 # Listen to 0.0.0.0 so it's accessible outside the container
private_key_path: /etc/headscale/private.key # The default /var/lib/headscale path is not writable in the container
db_path: /etc/headscale/db.sqlite # The default /var/lib/headscale path is not writable  in the container

4. Start the headscale server while working in the host headscale directory:

docker run \
  --name headscale \
  --detach \
  --rm \
  --volume $(pwd)/config:/etc/headscale/ \
  --publish 0.0.0.0:8080:8080 \
  --publish 127.0.0.1:9090:9090 \
  headscale/headscale:<VERSION> \
  headscale serve

This command will mount config/ under /etc/headscale, forward port 8080 out of the container so the headscale instance becomes available and then detach so headscale runs in the background.

5. Verify headscale is running:

Follow the container logs:

docker logs --follow headscale

Verify running containers:

docker ps

Verify headscale is available:

curl http://127.0.0.1:9090/metrics

6. Create a namespace (tailnet):

docker exec headscale headscale namespaces create myfirstnamespace

Register a machine (normal login)

On a client machine, execute the tailscale login command:

tailscale up --login-server YOUR_HEADSCALE_URL

To register a machine when running headscale in a container, take the headscale command and pass it to the container:

docker exec headscale \
  headscale --namespace myfirstnamespace nodes register --key <YOU_+MACHINE_KEY>

Register machine using a pre authenticated key

Generate a key using the command line:

docker exec headscale \
  headscale --namespace myfirstnamespace preauthkeys create --reusable --expiration 24h

This will return a pre-authenticated key that can be used to connect a node to headscale during the tailscale command:

tailscale up --login-server <YOUR_HEADSCALE_URL> --authkey <YOUR_AUTH_KEY>

Debugging headscale running in Docker

The headscale/headscale Docker container is based on a "distroless" image that does not contain a shell or any other debug tools. If you need to debug your application running in the Docker container, you can use the -debug variant, for example headscale/headscale:x.x.x-debug.

Running the debug Docker container

To run the debug Docker container, use the exact same commands as above, but replace headscale/headscale:x.x.x with headscale/headscale:x.x.x-debug (x.x.x is the version of headscale). The two containers are compatible with each other, so you can alternate between them.

Executing commands in the debug container

The default command in the debug container is to run headscale, which is located at /bin/headscale inside the container.

Additionally, the debug container includes a minimalist Busybox shell.

To launch a shell in the container, use:

docker run -it headscale/headscale:x.x.x-debug sh

You can also execute commands directly, such as ls /bin in this example:

docker run headscale/headscale:x.x.x-debug ls /bin

Using docker exec allows you to run commands in an existing container.