Merge pull request #1978 from filbranden/systemd5

Remove detection for scope properties, which have always been broken

libcontainer/cgroups/systemd/apply_systemd.go

@@ -76,8 +76,6 @@ var (
 	theConn                    *systemdDbus.Conn
 	hasStartTransientUnit      bool
 	hasStartTransientSliceUnit bool
-	hasTransientDefaultDependencies bool
-	hasDelegateScope                bool
 	hasDelegateSlice           bool
 )
 
@@ -116,53 +114,6 @@ func UseSystemd() bool {
 			}
 		}
 
-		// Ensure the scope name we use doesn't exist. Use the Pid to
-		// avoid collisions between multiple libcontainer users on a
-		// single host.
-		scope := fmt.Sprintf("libcontainer-%d-systemd-test-default-dependencies.scope", os.Getpid())
-		testScopeExists := true
-		for i := 0; i <= testScopeWait; i++ {
-			if _, err := theConn.StopUnit(scope, "replace", nil); err != nil {
-				if dbusError, ok := err.(dbus.Error); ok {
-					if strings.Contains(dbusError.Name, "org.freedesktop.systemd1.NoSuchUnit") {
-						testScopeExists = false
-						break
-					}
-				}
-			}
-			time.Sleep(time.Millisecond)
-		}
-
-		// Bail out if we can't kill this scope without testing for DefaultDependencies
-		if testScopeExists {
-			return hasStartTransientUnit
-		}
-
-		// Assume StartTransientUnit on a scope allows DefaultDependencies
-		hasTransientDefaultDependencies = true
-		ddf := newProp("DefaultDependencies", false)
-		if _, err := theConn.StartTransientUnit(scope, "replace", []systemdDbus.Property{ddf}, nil); err != nil {
-			if dbusError, ok := err.(dbus.Error); ok {
-				if strings.Contains(dbusError.Name, "org.freedesktop.DBus.Error.PropertyReadOnly") {
-					hasTransientDefaultDependencies = false
-				}
-			}
-		}
-
-		// Not critical because of the stop unit logic above.
-		theConn.StopUnit(scope, "replace", nil)
-
-		// Assume StartTransientUnit on a scope allows Delegate
-		hasDelegateScope = true
-		dlScope := newProp("Delegate", true)
-		if _, err := theConn.StartTransientUnit(scope, "replace", []systemdDbus.Property{dlScope}, nil); err != nil {
-			if dbusError, ok := err.(dbus.Error); ok {
-				if strings.Contains(dbusError.Name, "org.freedesktop.DBus.Error.PropertyReadOnly") {
-					hasDelegateScope = false
-				}
-			}
-		}
-
 		// Assume we have the ability to start a transient unit as a slice
 		// This was broken until systemd v229, but has been back-ported on RHEL environments >= 219
 		// For details, see: https://bugzilla.redhat.com/show_bug.cgi?id=1370299
@@ -207,7 +158,6 @@ func UseSystemd() bool {
 		}
 
 		// Not critical because of the stop unit logic above.
-		theConn.StopUnit(scope, "replace", nil)
 		theConn.StopUnit(slice, "replace", nil)
 	}
 	return hasStartTransientUnit
@@ -268,10 +218,9 @@ func (m *Manager) Apply(pid int) error {
 			properties = append(properties, newProp("Delegate", true))
 		}
 	} else {
-		if hasDelegateScope {
+		// Assume scopes always support delegation.
 		properties = append(properties, newProp("Delegate", true))
 	}
-	}
 
 	// Always enable accounting, this gets us the same behaviour as the fs implementation,
 	// plus the kernel has some problems with joining the memory cgroup at a later time.
@@ -280,10 +229,9 @@ func (m *Manager) Apply(pid int) error {
 		newProp("CPUAccounting", true),
 		newProp("BlockIOAccounting", true))
 
-	if hasTransientDefaultDependencies {
+	// Assume DefaultDependencies= will always work (the check for it was previously broken.)
 	properties = append(properties,
 		newProp("DefaultDependencies", false))
-	}
 
 	if c.Resources.Memory != 0 {
 		properties = append(properties,