Tailscale on AWS App Runner

AWS App Runner is a fully managed means of running container workloads on AWS. Deployment in App Runner can make it difficult to use Tailscale, since it doesn't provide a /dev/net/tun device that Tailscale needs.

You can use Tailscale's userspace networking mode to connect your AWS App Runner containers to your Tailscale network.

Step 1: Generate an auth key to authenticate your AWS App Runner containers

First, we'll generate an auth key to allow AWS App Runner to authenticate our container to join our network.

Open the Keys page of the admin console and select Generate auth key. We recommend using an ephemeral key for this purpose, since it will automatically clean up devices after they shut down.

Next, navigate to the AWS App Runner Services list, and create a new service. In the Configuration tab, scroll down to Service Settings and look for Environment Variables. Add a variable with key TAILSCALE_AUTHKEY and a value of the tskey-<key> string generated earlier.

Step 2: Configure your Dockerfile to install Tailscale

Next, we'll use a multistage Dockerfile, where the first stage builds your application, and the second stage pulls application code and Tailscale into the final image to be uploaded to AWS.

In your Dockerfile:

FROM alpine:latest as builder
WORKDIR /app
COPY . ./
# This is where one could build the application code as well.

FROM alpine:latest
# Copy binary to production image.
COPY --from=builder /app/bootstrap /var/runtime/bootstrap

# Copy Tailscale binaries from the tailscale image on Docker Hub.
COPY --from=docker.io/tailscale/tailscale:stable /usr/local/bin/tailscaled /var/runtime/tailscaled
COPY --from=docker.io/tailscale/tailscale:stable /usr/local/bin/tailscale /var/runtime/tailscale
RUN mkdir -p /var/run && ln -s /tmp/tailscale /var/run/tailscale && \
    mkdir -p /var/cache && ln -s /tmp/tailscale /var/cache/tailscale && \
    mkdir -p /var/lib && ln -s /tmp/tailscale /var/lib/tailscale && \
    mkdir -p /var/task && ln -s /tmp/tailscale /var/task/tailscale

# Run on container startup.
ENTRYPOINT ["/var/runtime/bootstrap"]

The Dockerfile specifies /var/runtime/bootstrap as the initial process to run. This script needs to bring Tailscale up and then start the application binary. This is where we can use the TAILSCALE_AUTHKEY variable we defined earlier.

Then, create a file named bootstrap at the root of your app:

#!/bin/sh

mkdir -p /tmp/tailscale
/var/runtime/tailscaled --tun=userspace-networking --socks5-server=localhost:1055 &
/var/runtime/tailscale up --auth-key=${TAILSCALE_AUTHKEY} --hostname=aws-apprunner-app
echo Tailscale started
ALL_PROXY=socks5://localhost:1055/ /var/runtime/my-app

Done! When your AWS App Runner container deploys, it should be able to connect to your private Tailscale network.

Remove ephemeral nodes from a tailnet

When an ephemeral node goes offline, it is automatically removed from your tailnet. You can also control ephemeral node removal using the tailscale logout command to either manually force the removal or incorporate the command into the tailscaled Tailscale daemon. For more information, see Ephemeral nodes.