Support dracut booting with GRUB

Signed-off-by: Jonathon Anderson <janderson@ciq.com>

CHANGELOG.md

@@ -41,7 +41,9 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 - Add `stage=initramfs` to warewulfd provision to serve initramfs from container image. #1115
 - Add `warewulf-dracut` package to support building Warewulf-compatible initramfs images with dracut. #1115
 - Add iPXE template `dracut.ipxe` to boot a dracut initramfs. #1115
-- Add `.NetDevs` variable to iPXE templates, similar to overlay templates. #1115
+- Add dracut menuentry to `grub.cfg.ww` to boot a dracut initramfs. #1115
+- Add `.NetDevs` variable to iPXE and GRUB templates, similar to overlay templates. #1115
+- Add `.Tags` variable to iPXE and GRUB templates, similar to overlay templates. #1115
 
 ### Changed
 

etc/grub/grub.cfg.ww

@@ -6,13 +6,16 @@ echo "Warewulf Controller: {{.Ipaddr}}"
 echo
 sleep 1
 smbios --type1 --get-string 8 --set assetkey
+
 uri="(http,{{.Ipaddr}}:{{.Port}})/provision/${net_default_mac}?assetkey=${assetkey}"
 kernel="${uri}&stage=kernel"
 container="${uri}&stage=container&compress=gz"
 system="${uri}&stage=system&compress=gz"
 runtime="${uri}&stage=runtime&compress=gz"
-set default=ww4
+
+set default={{ or .Tags.GrubMenuEntry "ww4" }}
 set timeout=5
+
 menuentry "Network boot node: {{.Id}}" --id ww4 {
     {{if .KernelOverride }}
     echo "Kernel:                {{.KernelOverride}}"
@@ -34,17 +37,54 @@ menuentry "Network boot node: {{.Id}}" --id ww4 {
         reboot
     fi
 }
+
+menuentry "Network boot node with dracut: {{.Id}}" --id dracut {
+    initramfs="${uri}&stage=initramfs"
+
+    uri="http://{{.Ipaddr}}:{{.Port}}/provision/${net_default_mac}?assetkey=${assetkey}"
+    container="${uri}&stage=container&compress=gz"
+    system="${uri}&stage=system&compress=gz"
+    runtime="${uri}&stage=runtime&compress=gz"
+
+    {{if .KernelOverride }}
+    echo "Kernel:                {{.KernelOverride}}"
+    {{else}}
+    echo "Kernel:                {{.ContainerName}} (container default)"
+    {{end}}
+    echo "KernelArgs:            {{.KernelArgs}}"
+
+    net_args="rd.neednet=1 {{range $devname, $netdev := .NetDevs}}{{if and $netdev.Hwaddr $netdev.Device}} ifname={{$netdev.Device}}:{{$netdev.Hwaddr}} {{end}}{{end}}"
+    wwinit_args="root=wwinit wwinit.container=${container} wwinit.system=${system} wwinit.runtime=${runtime} init=/init"
+    linux $kernel wwid=${net_default_mac} {{.KernelArgs}} $net_args $wwinit_args
+
+    if [ x$? = x0 ] ; then
+        echo "Loading Container:     {{.ContainerName}}"
+        initrd $initramfs
+        boot
+    else
+        echo "MESSAGE: This node seems to be unconfigured. Please have your system administrator add a"
+        echo "         configuration for this node with HW address: ${net_default_mac}"
+        echo ""
+        echo "Rebooting in 1 minute..."
+        sleep 60
+        reboot
+    fi
+}
+
 menuentry "Chainload specific configfile" {
     conf="(http,{{.Ipaddr}}:{{.Port}})/efiboot/grub.cfg"
     configfile $conf
 }
+
 menuentry "UEFI Firmware Settings" --id "uefi-firmware" {
     fwsetup
 }
+
 menuentry "System restart" {
     echo "System rebooting..."
     reboot
 }
+
 menuentry "System shutdown" {
     echo "System shutting down..."
     halt

internal/pkg/warewulfd/provision.go

@@ -34,6 +34,7 @@ type templateVars struct {
 	Port           string
 	KernelArgs     string
 	KernelOverride string
+	Tags           map[string]string
 	NetDevs        map[string]*node.NetDevs
 }
 
@@ -108,7 +109,8 @@ func ProvisionSend(w http.ResponseWriter, req *http.Request) {
 			ContainerName:  node.ContainerName.Get(),
 			KernelArgs:     node.Kernel.Args.Get(),
 			KernelOverride: node.Kernel.Override.Get(),
-			NetDevs:        tstruct.NetDevs}
+			NetDevs:        tstruct.NetDevs,
+			Tags:           tstruct.Tags}
 	} else if rinfo.stage == "kernel" {
 		if node.Kernel.Override.Defined() {
 			stage_file = kernel.KernelImage(node.Kernel.Override.Get())
@@ -180,6 +182,7 @@ func ProvisionSend(w http.ResponseWriter, req *http.Request) {
 			}
 		case "grub.cfg":
 			stage_file = path.Join(conf.Paths.Sysconfdir, "warewulf/grub/grub.cfg.ww")
+			tstruct := overlay.InitStruct(&node)
 			tmpl_data = templateVars{
 				Id:             node.Id.Get(),
 				Cluster:        node.ClusterName.Get(),
@@ -190,7 +193,9 @@ func ProvisionSend(w http.ResponseWriter, req *http.Request) {
 				Hwaddr:         rinfo.hwaddr,
 				ContainerName:  node.ContainerName.Get(),
 				KernelArgs:     node.Kernel.Args.Get(),
-				KernelOverride: node.Kernel.Override.Get()}
+				KernelOverride: node.Kernel.Override.Get(),
+				NetDevs:        tstruct.NetDevs,
+				Tags:           tstruct.Tags}
 			if stage_file == "" {
 				wwlog.ErrorExc(fmt.Errorf("could't find grub.cfg template"), containerName)
 				w.WriteHeader(http.StatusNotFound)

userdocs/contents/boot-management.rst

@@ -74,10 +74,27 @@ booting the node image directly.
 
    The iPXE template may be set at the node or profile level.
 
+Alternatively, to direct GRUB to fetch the node's initramfs image and boot with
+dracut semantics, set a ``GrubMenuEntry`` tag for the node.
+
+.. note::
+
+   Warewulf configures GRUB with a template located at
+   ``/etc/warewulf/grub/grub.cfg.ww``. Inspect the template to learn more about
+   the dracut booting process.
+
+.. code-block:: shell
+
+   wwctl node set wwnode1 --tagadd GrubMenuEntry=dracut
+
+.. note::
+
+   The ``GrubMenuEntry`` variable may be set at the node or profile level.
+
 During boot, ``warewulfd`` will detect and dynamically serve an
 initramfs from a node's container image in much the same way that it
 can serve a kernel from a container image. This image is loaded by
-iPXE, and iPXE directs dracut to fetch the node's container image
+iPXE (or GRUB) which directs dracut to fetch the node's container image
 during boot.
 
 The wwinit module provisions to tmpfs. By default, tmpfs is permitted
@@ -88,7 +105,7 @@ more details.)
 
 .. warning::
 
-   Kernel overrides are not currently supported during dracut initramfs boot.
+   Kernel overrides are not currently fully supported during dracut initramfs boot.
 
 Booting with GRUB
 =================