I followed README.md and got to this step (but no further):
$ nixops deploy -d hydra
building all machine configurations...
error: The option `services.hydra' defined in `/home/bfo/forks/hydra-tutorial/hydra-network.nix' does not exist.
(use ‘--show-trace’ to show detailed location information)
error: unable to build all machine configurations
Oh, there is more breakage after fixing that. For instance, the hydra module refers to gcc6. Better lock down the hydra tarball instead of always pulling from master.
I followed README.md and got to this step (but no further):
It's due to https://github.com/NixOS/hydra/commit/633724cc8aecc8fe7e586f81444bfd8d290be411 ("services.hydra -> services.hydra-dev").