+++
title = "Redeploying existing host"
taxonomies.categories = [ "nix" ]
+++

Execute the following script from the root of the haccfiles directory on a NixOS-based host (otherwise initrd secrets and therefore the encrypted boot **will** break).

```sh
nix build -f . deploy.$hostspec
./result $action
```

`$hostspec` can be replaced by any hostname or group name. To find out wich groups exist, evaluate the expression `lib.attrNames groups` in the context of the top-level default.nix.

`$action` can be one of:
- switch:       make the configuration the boot default and activate now
- boot:         make the configuration the boot default
- test:         activate the configuration, but don't make it the boot default
- dry-activate: show what would be done if this configuration were activated

It is recommended to run a dry-activate first, and if any of the changes mentioned have a chance of interrupting access to the server, executing a test and only once that succeeds a switch.