core: implicitly create a per-template slice for all instantiated units by default

If no explicit slice is configured for an instantiated unit, create an
implicit one for all instances of the same template.

1 files changed, 34 insertions, 1 deletions

diff --git a/src/core/unit.c b/src/core/unit.c
index 5bc57e25c6..bfde08d68c 100644
--- a/src/core/unit.c
+++ b/src/core/unit.c
@@ -2030,6 +2030,8 @@ char *unit_default_cgroup_path(Unit *u) {
 }
 
 int unit_add_default_slice(Unit *u) {
+        _cleanup_free_ char *b = NULL;
+        const char *slice_name;
         Unit *slice;
         int r;
 
@@ -2041,7 +2043,38 @@ int unit_add_default_slice(Unit *u) {
         if (!unit_get_cgroup_context(u))
                 return 0;
 
-        r = manager_load_unit(u->manager, u->manager->running_as == SYSTEMD_SYSTEM ? SPECIAL_SYSTEM_SLICE : SPECIAL_ROOT_SLICE, NULL, NULL, &slice);
+        if (u->instance) {
+                _cleanup_free_ char *prefix = NULL, *escaped = NULL;
+                        ;
+                /* Implicitly place all instantiated units in their
+                 * own per-template slice */
+
+                prefix = unit_name_to_prefix(u->id);
+                if (!prefix)
+                        return -ENOMEM;
+
+                /* The prefix is already escaped, but it might include
+                 * "-" which has a special meaning for slice units,
+                 * hence escape it here extra. */
+                escaped = strreplace(prefix, "-", "\\x2d");
+                if (!escaped)
+                        return -ENOMEM;
+
+                if (u->manager->running_as == SYSTEMD_SYSTEM)
+                        b = strjoin("system-", escaped, ".slice", NULL);
+                else
+                        b = strappend(escaped, ".slice");
+                if (!b)
+                        return -ENOMEM;
+
+                slice_name = b;
+        } else
+                slice_name =
+                        u->manager->running_as == SYSTEMD_SYSTEM
+                        ? SPECIAL_SYSTEM_SLICE
+                        : SPECIAL_ROOT_SLICE;
+
+        r = manager_load_unit(u->manager, slice_name, NULL, NULL, &slice);
         if (r < 0)
                 return r;