Merge pull request #1728 from cgwalters/add-grub2

Add optionally-installed grub2 code

Author: cgwalters

Makefile

@@ -30,6 +30,9 @@ install: all
 	ln -sf ../lib/dracut/modules.d/30ignition/ignition $(DESTDIR)/usr/libexec/ignition-apply
 	ln -sf ../lib/dracut/modules.d/30ignition/ignition $(DESTDIR)/usr/libexec/ignition-rmcfg
 
+install-grub-for-bootupd:
+	install -m 0644 -D -t $(DESTDIR)/usr/lib/bootupd/grub2-static/configs.d grub2/ignition.cfg
+
 .PHONY: vendor
 vendor:
 	@go mod vendor

docs/release-notes.md

@@ -12,6 +12,8 @@ nav_order: 9
 ### Features
 
 - Support Hetzner Cloud
+- A GRUB configuration suitable for use with https://github.com/coreos/bootupd
+  can now be installed; use `make install-grub-for-bootupd` to install it
 
 ### Changes
 

grub2/ignition.cfg

@@ -0,0 +1,19 @@
+# This GRUB config snippet implements the `ignition.firstboot` semantic using a
+# stamp file in the bootfs. This is used at least on CoreOS-based systems where
+# it's injected by https://github.com/coreos/bootupd.
+
+# Determine if this is a first boot and set the ${ignition_firstboot} variable
+# which is used in the kernel command line.
+set ignition_firstboot=""
+if [ -f "/ignition.firstboot" ]; then
+    # Default networking parameters to be used with Ignition.
+    set ignition_network_kcmdline=''
+
+    # Source in the `ignition.firstboot` file which could override the
+    # above $ignition_network_kcmdline with static networking config.
+    # This override feature is also used by coreos-installer to persist static
+    # networking config provided during install to the first boot of the machine.
+    source "/ignition.firstboot"
+
+    set ignition_firstboot="ignition.firstboot ${ignition_network_kcmdline}"
+fi