Hydra is a build/CI service based on nix. It is used to automatically build our nix infra.

Hydra is itself configured in the nix-infra repository. Furthermore the following configurations/integrations exist:

• A chaos-admin user exists for administering Hydra with the credentials accessible for the infra team in pass.
• Hydra has been configured to build the nix-infra repo in a project called nix-infra. The jobs for the main branch can be found here.
• The hydra periodically checks the nix-infra repo for changes and then re-evaluates and builds the repo, if needed.