tailscale-service-observer

tailscale-service-observer

Tailscale service observer is a Go tool which watches Kubernetes services in a single namespace and updates the advertised routes of a Tailscale client over the client's HTTP API (tailscale web).

Configuration

The observer expects to run in a context with a working Kubernetes configuration (either via kubeconfig file or in-cluster).

The environment variable TARGET_NAMESPACE must be set to the namespace(s) in which the observer should watch services. You can specify multiple namespaces separated by commas. The environment variable TAILSCALE_API_URL can be used to provide a custom URL for the Tailscale client's HTTP API. By default, the observer expects the API to be reachable at http://localhost:8088. The environment variable OBSERVER_ADDITIONAL_ROUTES can be used to advertise additional routes. You can specify multiple routes separated by commas. Entries which can be parsed as an IP address will be advertised as a <ip-address>/32 route. Entries which can be parsed as a CIDR prefix will be advertised as that prefix route.

See the examples for Kubernetes manifests to get started.

Expose the in-cluster DNS server in your tailnet

To expose the in-cluster DNS server in your tailnet, you can advertise the in-cluster DNS IP address by adding it in the environment variable OBSERVER_ADDITIONAL_ROUTES.

Additionally, you can enable Tailscale's MagicDNS feature, and add the in-cluster DNS server as an additional resolver. We recommend that you enable "Restrict to search domain", and set svc.cluster.local as the search domain. This allows you to use the in-cluster service DNS names (<service>.<namespace>.svc.cluster.local) to access advertised services.