nixserv — Nix Build Server

Purpose

nixserv is the dedicated binary cache and distributed build server for the cluster. It runs Attic backed by PostgreSQL and S3 storage, and acts as a remote build daemon for distributed Nix builds.

Entry Point

• Main file: hosts/server/nixserv/default.nix

Architecture / Services / Scope

Attic Binary Cache

• Attic: Self-hosted Nix binary cache server, served at cache.racci.dev.
• Storage is backed by the Storage Coordinator with zstd chunked/compressed NAR storage.
• The Attic database uses PostgreSQL on the Database Coordinator.
• Requires proof-of-possession for uploads, with a 14-day default garbage-collection retention period run on a schedule.

Distributed Builds

As a distributedBuilders host, nixserv exposes the builder user over SSH. Other hosts configure nix.distributedBuilds and connect to it as a remote build machine (ssh-ng) to offload Nix builds.

Secrets

Declared secrets

Operational Notes / Assumptions

• The cache endpoint and the build daemon rely on the Storage Coordinator for object storage and the Database Coordinator for the metadata database.
• The Attic HTTP endpoint is served through the IO Coordinator reverse proxy.

References

• Attic — Nix binary cache server
• Distributed Builds
• Database Coordinator
• Storage Coordinator
• IO Coordinator