Can I still use nixos-rebuild?

Yes, you can still use nixos-rebuild with clan!

Clan is built on top of standard NixOS and uses nixos-rebuild internally. However, there are important considerations when using nixos-rebuild directly instead of clan machines update.

Important Considerations

Vars Must Be Uploaded First

If your configuration uses clan vars, failing to run clan vars upload before nixos-rebuild will result in missing secrets and potentially broken services.

Build Host Configuration

Clan automatically handles build host configuration based on your machine settings. When using nixos-rebuild manually, you need to specify --build-host and --target-host options yourself.

How Clan Uses nixos-rebuild

Clan doesn't replace nixos-rebuild - it enhances it. When you run clan machines update, clan:

  1. Generates and uploads secrets/variables (if any)
  2. Uploads the flake source to the target/build host (if needed)
  3. Runs nixos-rebuild switch with the appropriate options
  4. Handles remote building and deployment automatically

Under the hood, clan executes commands like:

nixos-rebuild switch --fast --build-host builtHost --flake /path/to/flake#machine-name

When You Need clan vars upload

If your clan configuration uses variables (vars) - generated secrets, keys, or configuration values - you must run clan vars upload before using nixos-rebuild directly.

Systems that use vars include:

  • Any clanModules with generated secrets (zerotier, borgbackup, etc.)
  • Custom generators that create passwords or keys
  • Services that need shared configuration values

Systems that don't need vars:

  • Basic NixOS configurations without clan-specific services
  • Static configurations with hardcoded values
  • Systems using only traditional NixOS secrets management

Manual nixos-rebuild Workflow

When you want to use nixos-rebuild directly:

Step 1: Upload vars (if needed)

# Upload secret vars to the target machine
clan vars upload my-machine

Step 2: Run nixos-rebuild

nixos-rebuild switch --flake .#my-machine --target-host root@target-ip --build-host local