A flake must have a `deploy` output with the following structure: ``` deploy ├── └── nodes ├── │   ├── │   ├── hostname │   ├── profilesOrder │   └── profiles │   ├── │   │   ├── │   │   ├── bootstrap │   │   ├── profilePath │   │   └── path │   └── ... └── ... ``` Where `` are all optional and can be one or multiple of: - `sshUser` -- user to connect as - `user` -- user to install and activate profiles with - `sshOpts` -- options passed to `nix copy` and `ssh` - `fastConnection` -- whether the connection from this host to the target one is fast (if it is, don't substitute on target and copy the entire closure) [default: `false`] - `autoRollback` -- whether to roll back when the deployment fails [default: `false`] A formal definition for the structure can be found in [the JSON schema](./deploy.json) For every profile of every node, arguments are merged with `` taking precedence over `` and `` taking precedence over top-level. Certain read values can be overridden by supplying flags to the deploy binary, for example `deploy --auto-rollback true .` will enable automatic rollback for all nodes being deployed to, regardless of settings.