fix(os): ship systemd drop-ins as vendor config, not into /etc

os/mkosi/components/dstack-rust/dstack-rust-build.sh

@@ -7,8 +7,8 @@ DEST=$(realpath -m "$DEST")
 FLAVOR=${2:-prod}
 install -d "$DEST/usr/bin" "$DEST/usr/lib/systemd/system" \
   "$DEST/etc/systemd/journald.conf.d" "$DEST/etc/systemd/resolved.conf.d" \
-  "$DEST/etc/systemd/system/docker.service.d" \
-  "$DEST/etc/systemd/system/containerd.service.d" "$DEST/etc/sysctl.d"
+  "$DEST/usr/lib/systemd/system/docker.service.d" \
+  "$DEST/usr/lib/systemd/system/containerd.service.d" "$DEST/etc/sysctl.d"
 for s in dstack-prepare ephemeral-docker app-compose; do
   install -m0755 "$ROOT/os/common/rootfs/$s.sh" "$DEST/usr/bin/$s.sh"
 done
@@ -18,10 +18,11 @@ install -m0644 "$ROOT/os/common/rootfs/journald.conf" "$DEST/etc/systemd/journal
 install -m0644 "$ROOT/os/common/rootfs/llmnr.conf" "$DEST/etc/systemd/resolved.conf.d/dstack.conf"
 install -m0644 "$ROOT/os/common/rootfs/tdx-attest.conf" "$DEST/etc/"
 install -m0644 "$ROOT/os/common/rootfs/sysctl.d/99-dstack.conf" "$DEST/etc/sysctl.d/"
+# Vendor drop-ins go beside the units, not into the operator's /etc layer.
 install -m0644 "$ROOT/os/common/rootfs/docker.service.d/"* \
-  "$DEST/etc/systemd/system/docker.service.d/"
+  "$DEST/usr/lib/systemd/system/docker.service.d/"
 install -m0644 "$ROOT/os/common/rootfs/containerd.service.d/"* \
-  "$DEST/etc/systemd/system/containerd.service.d/"
+  "$DEST/usr/lib/systemd/system/containerd.service.d/"
 
 # Cargo.lock and --locked pin every registry/git dependency. The hermetic
 # mkosi build root may fetch missing inputs but cannot update the lock file.
@@ -77,7 +78,7 @@ if [[ ${DSTACK_SKIP_RUST:-0} != 1 ]]; then
     # else systemd never reads it and dstack-prepare loses its ordering against
     # the simulator that has to publish the TEE ABI first.
     install -Dm0644 "$ROOT/os/yocto/layers/meta-dstack/recipes-core/dstack-tee-simulator/files/tee-simulator.conf" \
-      "$DEST/etc/systemd/system/dstack-prepare.service.d/tee-simulator.conf"
+      "$DEST/usr/lib/systemd/system/dstack-prepare.service.d/tee-simulator.conf"
   fi
 fi
 find "$DEST" -print0 | xargs -0r touch --no-dereference --date="@${SOURCE_DATE_EPOCH:?}"

os/mkosi/parity.json

@@ -85,7 +85,7 @@
   "dev_only_paths": [
     "usr/bin/dstack-tee-simulator",
     "usr/bin/swtpm",
-    "etc/systemd/system/dstack-prepare.service.d/tee-simulator.conf",
+    "usr/lib/systemd/system/dstack-prepare.service.d/tee-simulator.conf",
     "usr/bin/strace",
     "usr/bin/gdb",
     "usr/sbin/sshd",
@@ -142,7 +142,7 @@
   "prod_forbidden_paths": [
     "usr/bin/dstack-tee-simulator",
     "usr/bin/swtpm",
-    "etc/systemd/system/dstack-prepare.service.d/tee-simulator.conf",
+    "usr/lib/systemd/system/dstack-prepare.service.d/tee-simulator.conf",
     "usr/bin/strace",
     "usr/bin/gdb",
     "usr/sbin/sshd",

os/yocto/layers/meta-dstack/recipes-core/dstack-guest/dstack-guest.bb

@@ -88,18 +88,21 @@ do_install() {
         install -m 0644 ${DSTACK_ROOTFS_FILES}/dstack-gateway-checker.service ${D}${systemd_system_unitdir}
         install -m 0644 ${DSTACK_ROOTFS_FILES}/dstack-guest-agent.socket ${D}${systemd_system_unitdir}
         install -m 0644 ${DSTACK_ROOTFS_FILES}/llmnr.conf ${D}${sysconfdir}/systemd/resolved.conf.d
-        install -d ${D}${sysconfdir}/systemd/system/docker.service.d
-        install -m 0644 ${DSTACK_ROOTFS_FILES}/docker.service.d/* ${D}${sysconfdir}/systemd/system/docker.service.d/
-
-        install -d ${D}${sysconfdir}/systemd/system/containerd.service.d
-        install -m 0644 ${DSTACK_ROOTFS_FILES}/containerd.service.d/* ${D}${sysconfdir}/systemd/system/containerd.service.d/
+        # Drop-ins the image ships are vendor configuration, so they belong
+        # beside the units in ${systemd_system_unitdir}. /etc is the operator's
+        # layer and `systemctl revert` deletes <unit>.d/ below it wholesale.
+        install -d ${D}${systemd_system_unitdir}/docker.service.d
+        install -m 0644 ${DSTACK_ROOTFS_FILES}/docker.service.d/* ${D}${systemd_system_unitdir}/docker.service.d/
+
+        install -d ${D}${systemd_system_unitdir}/containerd.service.d
+        install -m 0644 ${DSTACK_ROOTFS_FILES}/containerd.service.d/* ${D}${systemd_system_unitdir}/containerd.service.d/
     fi
 }
 
 FILES:${PN} += " \
-    ${sysconfdir}/systemd/system/docker.service.d/dstack-guest-agent.conf \
-    ${sysconfdir}/systemd/system/docker.service.d/dstack-prepare.conf \
-    ${sysconfdir}/systemd/system/containerd.service.d/dstack-prepare.conf \
+    ${systemd_system_unitdir}/docker.service.d/dstack-guest-agent.conf \
+    ${systemd_system_unitdir}/docker.service.d/dstack-prepare.conf \
+    ${systemd_system_unitdir}/containerd.service.d/dstack-prepare.conf \
 "
 
 # Cargo embeds build paths into binaries; allow TMPDIR references.

os/yocto/layers/meta-dstack/recipes-core/dstack-tee-simulator/dstack-tee-simulator.bb

@@ -52,9 +52,9 @@ do_install() {
     install -m 0644 ${THISDIR}/files/dstack-tee-simulator.service \
         ${D}${systemd_system_unitdir}
 
-    install -d ${D}${sysconfdir}/systemd/system/dstack-prepare.service.d
+    install -d ${D}${systemd_system_unitdir}/dstack-prepare.service.d
     install -m 0644 ${THISDIR}/files/tee-simulator.conf \
-        ${D}${sysconfdir}/systemd/system/dstack-prepare.service.d/tee-simulator.conf
+        ${D}${systemd_system_unitdir}/dstack-prepare.service.d/tee-simulator.conf
 }
 
 # Unit/drop-in live next to this recipe; include them in task checksums.
@@ -63,7 +63,7 @@ do_install[file-checksums] += "\
     ${THISDIR}/files/tee-simulator.conf:True \
 "
 
-FILES:${PN} += "${sysconfdir}/systemd/system/dstack-prepare.service.d/tee-simulator.conf"
+FILES:${PN} += "${systemd_system_unitdir}/dstack-prepare.service.d/tee-simulator.conf"
 
 # Cargo embeds build paths into binaries; allow TMPDIR references.
 INSANE_SKIP:${PN} += "buildpaths"