boot.mount: mount by UUID instead

overlay.d/05core/usr/lib/coreos/generator-lib.sh

@@ -17,3 +17,14 @@ have_karg() {
     done
     return 1
 }
+
+karg() {
+    local name="$1" value="${2:-}"
+    local cmdline=( $(</proc/cmdline) )
+    for arg in "${cmdline[@]}"; do
+        if [[ "${arg%%=*}" == "${name}" ]]; then
+            value="${arg#*=}"
+        fi
+    done
+    echo "${value}"
+}

overlay.d/05core/usr/lib/dracut/modules.d/35coreos-ignition/coreos-boot-edit.sh

@@ -31,5 +31,21 @@ rm -vrf ${initramfs_firstboot_network_dir}
 # append rootmap kargs to the BLS configs.
 root=$(karg root)
 if [ -z "${root}" ]; then
-    /usr/bin/rdcore rootmap /sysroot --boot-mount ${bootmnt}
+    rdcore rootmap /sysroot --boot-mount ${bootmnt}
+fi
+
+# And similarly, only inject boot= if it's not already present.
+boot=$(karg boot)
+if [ -z "${boot}" ]; then
+    # XXX: `rdcore rootmap --inject-boot-karg` or maybe `rdcore bootmap`
+    eval $(blkid -o export "${bootdev}")
+    if [ -z "${UUID}" ]; then
+        # This should never happen
+        echo "Boot filesystem ${bootdev} has no UUID" >&2
+        exit 1
+    fi
+    rdcore kargs --boot-mount ${bootmnt} --append boot=UUID=${UUID}
+    # but also put it in /run for the first boot real root mount
+    mkdir -p /run/coreos
+    echo "${UUID}" > /run/coreos/bootfs_uuid
 fi

overlay.d/05core/usr/lib/systemd/system-generators/coreos-boot-mount-generator

@@ -61,15 +61,50 @@ EOF
     add_wants "${unit_name}"
 }
 
+# Copied from
+# https://github.com/dracutdevs/dracut/blob/9491e599282d0d6bb12063eddbd192c0d2ce8acf/modules.d/99base/dracut-lib.sh#L586
+# rather than sourcing it.
+label_uuid_to_dev() {
+    local _dev
+    _dev="${1#block:}"
+    case "$_dev" in
+        LABEL=*)
+            echo "/dev/disk/by-label/$(echo "${_dev#LABEL=}" | sed 's,/,\\x2f,g;s, ,\\x20,g')"
+            ;;
+        PARTLABEL=*)
+            echo "/dev/disk/by-partlabel/$(echo "${_dev#PARTLABEL=}" | sed 's,/,\\x2f,g;s, ,\\x20,g')"
+            ;;
+        UUID=*)
+            echo "/dev/disk/by-uuid/$(echo "${_dev#UUID=}" | tr "[:upper:]" "[:lower:]")"
+            ;;
+        PARTUUID=*)
+            echo "/dev/disk/by-partuuid/$(echo "${_dev#PARTUUID=}" | tr "[:upper:]" "[:lower:]")"
+            ;;
+    esac
+}
+
 # If the root device is multipath, hook up /boot to use that too,
 # based on our custom udev rules in 90-coreos-device-mapper.rules
 # that creates "label found on mpath" links.
 # Otherwise, use the usual by-label symlink.
 # See discussion in https://github.com/coreos/fedora-coreos-config/pull/1022
 bootdev=/dev/disk/by-label/boot
-# TODO add equivalent of getargbool() so we handle rd.multipath=0
-if have_karg rd.multipath; then
+bootkarg=$(karg boot)
+mpath=$(karg rd.multipath)
+if [ -n "${mpath}" ] && [ "${mpath}" != 0 ]; then
     bootdev=/dev/disk/by-label/dm-mpath-boot
+# Newer nodes inject boot=UUID=..., but we support a larger subset of the dracut/fips API
+elif [ -n "${bootkarg}" ]; then
+    # Adapted from https://github.com/dracutdevs/dracut/blob/9491e599282d0d6bb12063eddbd192c0d2ce8acf/modules.d/01fips/fips.sh#L17
+    case "$bootkarg" in
+        LABEL=* | UUID=* | PARTUUID=* | PARTLABEL=*)
+            bootdev="$(label_uuid_to_dev "$bootkarg")";;
+        /dev/*) bootdev=$bootkarg;;
+        *) echo "Unknown boot karg '${bootkarg}'; falling back to ${bootdev}";;
+    esac
+# This is used for the first boot only
+elif [ -f /run/coreos/bootfs_uuid ]; then
+    bootdev=/dev/disk/by-uuid/$(cat /run/coreos/bootfs_uuid)
 fi
 
 # We mount read-only by default mostly to protect

tests/kola/reboot/test.sh

@@ -0,0 +1,47 @@
+#!/bin/bash
+set -xeuo pipefail
+# kola: {"platforms": "qemu"}
+
+# These are read-only not-necessarily-related checks that verify default system
+# configuration both on first and subsequent boots.
+
+ok() {
+    echo "ok" "$@"
+}
+
+fatal() {
+    echo "$@" >&2
+    exit 1
+}
+
+# /var
+varsrc=$(findmnt -nvr /var -o SOURCE)
+rootsrc=$(findmnt -nvr / -o SOURCE)
+[[ $(realpath "$varsrc") == $(realpath "$rootsrc") ]]
+ok "/var is backed by rootfs"
+
+# sanity-check that boot is mounted by UUID
+if ! systemctl cat boot.mount | grep -q What=/dev/disk/by-uuid; then
+  systemctl cat boot.mount
+  fatal "boot mounted not by UUID"
+fi
+ok "boot mounted by UUID"
+
+case "${AUTOPKGTEST_REBOOT_MARK:-}" in
+  "")
+      ok "first boot"
+      /tmp/autopkgtest-reboot rebooted
+      ;;
+
+  rebooted)
+      # check for expected default kargs
+      grep root=UUID= /proc/cmdline
+      ok "found root karg"
+
+      grep boot=UUID= /proc/cmdline
+      ok "found boot karg"
+
+      ok "second boot"
+      ;;
+  *) fatal "unexpected mark: ${AUTOPKGTEST_REBOOT_MARK}";;
+esac

tests/kola/root-reprovision/luks/test.sh

@@ -27,6 +27,13 @@ if ! grep prjquota <<< "${rootflags}"; then
 fi
 ok "root mounted with prjquota"
 
+# while we're here, sanity-check that boot is mounted by UUID
+if ! systemctl cat boot.mount | grep -q What=/dev/disk/by-uuid; then
+  systemctl cat boot.mount
+  fatal "boot mounted not by UUID"
+fi
+ok "boot mounted by UUID"
+
 case "${AUTOPKGTEST_REBOOT_MARK:-}" in
   "")
       # check that ignition-ostree-growfs ran
@@ -42,6 +49,10 @@ case "${AUTOPKGTEST_REBOOT_MARK:-}" in
       grep root=UUID= /proc/cmdline
       grep rd.luks.name= /proc/cmdline
       ok "found root kargs"
+
+      # while we're here, sanity-check that we have a boot=UUID karg too
+      grep boot=UUID= /proc/cmdline
+      ok "found boot karg"
       ;;
   *) fatal "unexpected mark: ${AUTOPKGTEST_REBOOT_MARK}";;
 esac