Merge pull request #429 from hqhq/hq_use_FindCgroupMountRoot

fix apply error when we not mount cpu subsystem

cgroups/fs/apply_raw.go

@@ -54,12 +54,10 @@ func getCgroupRoot() (string, error) {
 		return cgroupRoot, nil
 	}
 
-	// we can pick any subsystem to find the root
-	cpuRoot, err := cgroups.FindCgroupMountpoint("cpu")
+	root, err := cgroups.FindCgroupMountpointDir()
 	if err != nil {
 		return "", err
 	}
-	root := filepath.Dir(cpuRoot)
 
 	if _, err := os.Stat(root); err != nil {
 		return "", err

cgroups/utils.go

@@ -34,6 +34,21 @@ func FindCgroupMountpoint(subsystem string) (string, error) {
 	return "", NewNotFoundError(subsystem)
 }
 
+func FindCgroupMountpointDir() (string, error) {
+	mounts, err := mount.GetMounts()
+	if err != nil {
+		return "", err
+	}
+
+	for _, mount := range mounts {
+		if mount.Fstype == "cgroup" {
+			return filepath.Dir(mount.Mountpoint), nil
+		}
+	}
+
+	return "", NewNotFoundError("cgroup")
+}
+
 type Mount struct {
 	Mountpoint string
 	Subsystems []string