privatae-bastion/docs/service-slot.md

Service slot: a server your host built, with no network

A host can leave a server running here, such as a private git server: an image started with every capability dropped, no new privileges, one data directory, and no network at all. It serves on a unix socket, and the host's tunnel is the only way in; the bastion checks on every connection that the socket belongs to the server's own user. Reaching a server needs a reach grant you approved, naming that host and that server. If the server should mirror public repositories, this machine does the fetching over its own connection (public internet only, https, no redirects) and pushes into the server. It is its own capability family, services. Linux only, and only where a container runtime is installed.