New warewulf-dracut subpackage

warewulf-dracut includes a dracut module to be installed in a container
image to support building an initramfs that can boot from Warewulf.

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

CHANGELOG.md

@@ -39,6 +39,7 @@ The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.0.0/).
 
 - Add examples for building overlays in parallel to documentation
 - 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
 
 ### Changed
 

Makefile

@@ -138,6 +138,8 @@ install: build docs
 	install -m 0644 etc/bash_completion.d/wwctl $(DESTDIR)$(BASHCOMPDIR)/wwctl
 	for f in docs/man/man1/*.1.gz; do install -m 0644 $$f $(DESTDIR)$(MANDIR)/man1/; done
 	for f in docs/man/man5/*.5.gz; do install -m 0644 $$f $(DESTDIR)$(MANDIR)/man5/; done
+	install -pd -m 0755 $(DESTDIR)$(DRACUTMODDIR)/90wwinit
+	install -m 0644 dracut/modules.d/90wwinit/*.sh $(DESTDIR)$(DRACUTMODDIR)/90wwinit
 
 .PHONY: installapi
 installapi:

Variables.mk

@@ -44,10 +44,11 @@ else
 endif
 
 # OS-Specific Service Locations
-VARLIST += TFTPDIR FIREWALLDDIR SYSTEMDDIR BASHCOMPDIR
+VARLIST += TFTPDIR FIREWALLDDIR SYSTEMDDIR BASHCOMPDIR DRACUTMODDIR
 SYSTEMDDIR ?= /usr/lib/systemd/system
 BASHCOMPDIR ?= /etc/bash_completion.d
 FIREWALLDDIR ?= /usr/lib/firewalld/services
+DRACUTMODDIR ?= /usr/lib/dracut/modules.d
 ifeq ($(OS),suse)
   TFTPDIR ?= /srv/tftpboot
 endif

dracut/modules.d/90wwinit/load-wwinit.sh

@@ -0,0 +1,13 @@
+#!/bin/bash
+
+info "Mounting tmpfs at $NEWROOT"
+mount -t tmpfs ${wwinit_tmpfs_size_option} tmpfs "$NEWROOT"
+
+for archive in "${wwinit_container}" "${wwinit_kmods}" "${wwinit_system}" "${wwinit_runtime}"
+do
+    if [ -n "${archive}" ]
+    then
+        info "Loading ${archive}"
+        (curl --silent -L "${archive}" | gzip -d | cpio -im --directory="${NEWROOT}") || die "Unable to load ${archive}"
+    fi
+done

dracut/modules.d/90wwinit/module-setup.sh

@@ -0,0 +1,20 @@
+#!/bin/bash
+
+check() {
+    # Don't include in hostonly mode
+    [[ $hostonly ]] && return 1
+
+    # Don't include by default
+    return 255
+}
+
+depends() {
+    echo network
+    return 0
+}
+
+install() {
+    inst_multiple cpio curl
+    inst_hook cmdline 30 "$moddir/parse-wwinit.sh"
+    inst_hook pre-mount 30 "$moddir/load-wwinit.sh"
+}

dracut/modules.d/90wwinit/parse-wwinit.sh

@@ -0,0 +1,28 @@
+#!/bin/sh
+# root=wwinit
+
+[ -z "$root" ] && root=$(getarg root=)
+
+if [ "${root}" = "wwinit" ]
+then
+    info "root=${root}"
+    export wwinit_container=$(getarg wwinit.container=); info "wwinit.container=${wwinit_container}"
+    export wwinit_system=$(getarg wwinit.system=); info "wwinit.system=${wwinit_system}"
+    export wwinit_runtime=$(getarg wwinit.runtime=); info "wwinit.runtime=${wwinit_runtime}"
+    export wwinit_kmods=$(getarg wwinit.kmods=); info "wwinit.kmods=${wwinit_kmods}"
+
+    wwinit_tmpfs_size=$(getarg wwinit.tmpfs.size=)
+    if [ -n "$wwinit_tmpfs_size" ]
+    then
+        info "wwinit.tmpfs.size=${wwinit_tmpfs_size}"
+        export wwinit_tmpfs_size_option="-o size=${wwinit_tmpfs_size}"
+    fi
+
+    if [ -n "${wwinit_container}" ]
+    then
+        info "Found root=${root} and a Warewulf container image. Will boot from Warewulf."
+        rootok=1
+    else
+        die "Found root=${root} but no container image. Cannot boot from Warewulf."
+    fi
+fi

warewulf.spec.in

@@ -82,6 +82,23 @@ BuildRequires: libassuan-devel gpgme-devel
 Warewulf is a stateless and diskless container operating system provisioning
 system for large clusters of bare metal and/or virtual systems.
 
+%package dracut
+Summary: dracut module for loading a Warewulf container image
+BuildArch: noarch
+
+Requires: dracut
+%if 0%{?suse_version}
+%else
+Requires: dracut-network
+%endif
+
+%description dracut
+Warewulf is a stateless and diskless container operating system provisioning
+system for large clusters of bare metal and/or virtual systems.
+
+This subpackage contains a dracut module that can be used to generate
+an initramfs that can fetch and boot a Warewulf container image from a
+Warewulf server.
 
 %prep
 %setup -q -n %{name}-%{version} -b0 %if %{?with_offline:-a2}
@@ -105,7 +122,8 @@ make defaults \
     BASHCOMPDIR=/etc/bash_completion.d/ \
     FIREWALLDDIR=/usr/lib/firewalld/services \
     WWCLIENTDIR=/warewulf \
-    IPXESOURCE=/usr/share/ipxe
+    IPXESOURCE=/usr/share/ipxe \
+    DRACUTMODDIR=/usr/lib/dracut/modules.d
 make
 %if %{api}
 make api
@@ -185,7 +203,16 @@ getent group %{wwgroup} >/dev/null || groupadd -r %{wwgroup}
 %endif
 
 
+%files dracut
+%defattr(-, root, root)
+%dir %{_prefix}/lib/dracut/modules.d/90wwinit
+%{_prefix}/lib/dracut/modules.d/90wwinit/*.sh
+
+
 %changelog
+* Thu Apr 18 2024 Jonathon Anderson <janderson@ciq.com>
+- New warewulf-dracut subpackage
+
 * Wed Apr 17 2024 Jonathon Anderson <janderson@ciq.com>
 - Don't build the API on EL7