nixos/activation/bootspec: add bootspec chapter in NixOS manual

2 files changed, 37 insertions, 0 deletions

diff --git a/nixos/doc/manual/development/bootspec.chapter.md b/nixos/doc/manual/development/bootspec.chapter.md
new file mode 100644
index 00000000000..96c12f24e7f
--- /dev/null
+++ b/nixos/doc/manual/development/bootspec.chapter.md
@@ -0,0 +1,36 @@
+# Experimental feature: Bootspec {#sec-experimental-bootspec}
+
+Bootspec is a experimental feature, introduced in the [RFC-0125 proposal](https://github.com/NixOS/rfcs/pull/125), the reference implementation can be found [there](https://github.com/NixOS/nixpkgs/pull/172237) in order to standardize bootloader support
+and advanced boot workflows such as SecureBoot and potentially more.
+
+You can enable the creation of bootspec documents through [`boot.bootspec.enable = true`](options.html#opt-boot.bootspec.enable), which will prompt a warning until [RFC-0125](https://github.com/NixOS/rfcs/pull/125) is officially merged.
+
+## Schema {#sec-experimental-bootspec-schema}
+
+The bootspec schema is versioned and validated against [a CUE schema file](https://cuelang.org/) which should considered as the source of truth for your applications.
+
+You will find the current version [here](../../../modules/system/activation/bootspec.cue).
+
+## Extensions mechanism {#sec-experimental-bootspec-extensions}
+
+Bootspec cannot account for all usecases.
+
+For this purpose, Bootspec offers a generic extension facility [`boot.bootspec.extensions`](options.html#opt-boot.bootspec.extensions) which can be used to inject any data needed for your usecases.
+
+An example for SecureBoot is to get the Nix store path to `/etc/os-release` in order to bake it into a unified kernel image:
+
+```nix
+{ config, lib, ... }: {
+  boot.bootspec.extensions = {
+    "org.secureboot.osRelease" = config.environment.etc."os-release".source;
+  };
+}
+```
+
+To reduce incompatibility and prevent names from clashing between applications, it is **highly recommended** to use a unique namespace for your extensions.
+
+## External bootloaders {#sec-experimental-bootspec-external-bootloaders}
+
+It is possible to enable your own bootloader through [`boot.loader.external.installHook`](options.html#opt-boot.loader.external.installHook) which can wrap an existing bootloader.
+
+Currently, there is no good story to compose existing bootloaders to enrich their features, e.g. SecureBoot, etc. It will be necessary to reimplement or reuse existing parts.
diff --git a/nixos/doc/manual/development/development.xml b/nixos/doc/manual/development/development.xml
index 624ee393165..949468c9021 100644
--- a/nixos/doc/manual/development/development.xml
+++ b/nixos/doc/manual/development/development.xml
@@ -12,6 +12,7 @@
  <xi:include href="../from_md/development/sources.chapter.xml" />
  <xi:include href="../from_md/development/writing-modules.chapter.xml" />
  <xi:include href="../from_md/development/building-parts.chapter.xml" />
+ <xi:include href="../from_md/development/bootspec.chapter.xml" />
  <xi:include href="../from_md/development/what-happens-during-a-system-switch.chapter.xml" />
  <xi:include href="../from_md/development/writing-documentation.chapter.xml" />
  <xi:include href="../from_md/development/nixos-tests.chapter.xml" />