ignition-ostree: Split unit for sysroot mounting

The unit to mount sysroot only worked the *first* boot
because it was integrated with Ignition.  We need to have
separate units with different dependencies (but that execute
the same code) for the "Ignition boot" compared with "subsequent"
boots.

Depends coreos/ignition-dracut#131

overlay.d/05core/usr/lib/dracut/modules.d/40ignition-ostree/ignition-ostree-mount-sysroot.service → overlay.d/05core/usr/lib/dracut/modules.d/40ignition-ostree/ignition-ostree-mount-firstboot-sysroot.service

@@ -1,11 +1,14 @@
 [Unit]
-Description=Mount OSTree /sysroot
+Description=Ignition OSTree: Mount (firstboot) /sysroot
+# These dependencies should match the "other" in
+# ignition-ostree-mount-subsequent-sysroot.service
 DefaultDependencies=false
 # If root is specified, then systemd's generator will win
 ConditionKernelCommandLine=!root
 ConditionKernelCommandLine=ostree
 ConditionPathExists=!/run/ostree-live
-
+# There can be only one, Highlander style
+Conflicts=ignition-ostree-mount-subsequent-sysroot.service
 Before=initrd-root-fs.target
 After=ignition-disks.service
 # These have an explicit dependency on After=sysroot.mount today

overlay.d/05core/usr/lib/dracut/modules.d/40ignition-ostree/ignition-ostree-mount-subsequent-sysroot.service

@@ -0,0 +1,23 @@
+[Unit]
+Description=CoreOS: Mount (subsequent) /sysroot
+# These dependencies should match the "other" in
+# ignition-ostree-mount-firsboot-sysroot.service
+DefaultDependencies=false
+# If root is specified, then systemd's generator will win
+ConditionKernelCommandLine=!root
+ConditionKernelCommandLine=ostree
+ConditionPathExists=!/run/ostree-live
+# There can be only one, Highlander style
+Conflicts=ignition-ostree-mount-firstboot-sysroot.service
+# And in contrast to the firstboot, we expect
+# the root device to be ready.
+Requires=dev-disk-by\x2dlabel-root.device
+After=dev-disk-by\x2dlabel-root.device
+Before=initrd-root-fs.target
+# This has an explicit dependency on After=sysroot.mount today
+Before=ostree-prepare-root.service
+
+[Service]
+Type=oneshot
+RemainAfterExit=yes
+ExecStart=/usr/sbin/ignition-ostree-mount-sysroot

overlay.d/05core/usr/lib/dracut/modules.d/40ignition-ostree/module-setup.sh

@@ -7,27 +7,26 @@ depends() {
 }
 
 install_ignition_unit() {
-    unit=$1; shift
+    local unit=$1; shift
+    local target=${1:-complete}
     inst_simple "$moddir/$unit" "$systemdsystemunitdir/$unit"
-    ln_r "../$unit" "$systemdsystemunitdir/ignition-complete.target.requires/$unit"
+    local targetpath="$systemdsystemunitdir/ignition-${target}.target.requires/"
+    mkdir -p "${initdir}/${targetpath}"
+    ln_r "../$unit" "${targetpath}/${unit}"
 }
 
 install() {
     inst_multiple \
         systemd-sysusers \
         systemd-tmpfiles
 
-    mkdir -p "$initdir/$systemdsystemunitdir/ignition-complete.target.requires"
+    for x in mount populate; do
+        install_ignition_unit ignition-ostree-${x}-var.service
+        inst_script "$moddir/ignition-ostree-${x}-var.sh" "/usr/sbin/ignition-ostree-${x}-var"
+    done
 
-    install_ignition_unit ignition-ostree-mount-var.service
-    inst_script "$moddir/ignition-ostree-mount-var.sh" \
-        "/usr/sbin/ignition-ostree-mount-var"
-
-    install_ignition_unit ignition-ostree-populate-var.service
-    inst_script "$moddir/ignition-ostree-populate-var.sh" \
-        "/usr/sbin/ignition-ostree-populate-var"
-
-    install_ignition_unit ignition-ostree-mount-sysroot.service
+    install_ignition_unit ignition-ostree-mount-firstboot-sysroot.service
+    install_ignition_unit ignition-ostree-mount-subsequent-sysroot.service subsequent
     inst_script "$moddir/ignition-ostree-mount-sysroot.sh" \
         "/usr/sbin/ignition-ostree-mount-sysroot"
 }