core: don't use the unified hierarchy for the systemd cgroup yet (#4628)

Too many things don't get along with the unified hierarchy yet:

 * https://github.com/opencontainers/runc/issues/1175
 * https://github.com/docker/docker/issues/28109
 * https://github.com/lxc/lxc/issues/1280

So revert the default to the legacy hierarchy for now. Developers of the above
software can opt into the unified hierarchy with
"systemd.legacy_systemd_cgroup_controller=0".

diff --git a/src/basic/cgroup-util.c b/src/basic/cgroup-util.c
index 5e73753935a8045cd069b5a62e6e2a1e87806b52..dc13025115f6ba5129e9d7ef38810ddcd7aebc9c 100644 (file)
--- a/src/basic/cgroup-util.c
+++ b/src/basic/cgroup-util.c
@@ -2423,10 +2423,10 @@ bool cg_is_unified_systemd_controller_wanted(void) {
 
                 r = get_proc_cmdline_key("systemd.legacy_systemd_cgroup_controller=", &value);
                 if (r < 0)
-                        return true;
+                        return false;
 
                 if (r == 0)
-                        wanted = true;
+                        wanted = false;
                 else
                         wanted = parse_boolean(value) <= 0;
         }