Replace Cgroup Parent and Name fields by CgroupsPath

Fixes #396

Signed-off-by: Kenfe-Mickael Laventure <mickael.laventure@gmail.com>

libcontainer/cgroups/fs/apply_raw.go

@@ -95,11 +95,10 @@ func getCgroupRoot() (string, error) {
 }
 
 type cgroupData struct {
-	root   string
-	parent string
-	name   string
-	config *configs.Cgroup
-	pid    int
+	root        string
+	cgroupspath string
+	config      *configs.Cgroup
+	pid         int
 }
 
 func (m *Manager) Apply(pid int) (err error) {
@@ -280,15 +279,11 @@ func getCgroupData(c *configs.Cgroup, pid int) (*cgroupData, error) {
 		return nil, err
 	}
 
-	// Clean the parent slice path.
-	c.Parent = libcontainerUtils.PathClean(c.Parent)
-
 	return &cgroupData{
-		root:   root,
-		parent: c.Parent,
-		name:   c.Name,
-		config: c,
-		pid:    pid,
+		root:        root,
+		cgroupspath: libcontainerUtils.PathClean(c.CgroupsPath),
+		config:      c,
+		pid:         pid,
 	}, nil
 }
 
@@ -316,7 +311,7 @@ func (raw *cgroupData) path(subsystem string) (string, error) {
 		return "", err
 	}
 
-	cgPath := filepath.Join(raw.parent, raw.name)
+	cgPath := raw.cgroupspath
 	// If the cgroup name/path is absolute do not look relative to the cgroup of the init process.
 	if filepath.IsAbs(cgPath) {
 		// Sometimes subsystems can be mounted togethger as 'cpu,cpuacct'.

libcontainer/cgroups/systemd/apply_systemd.go

@@ -19,6 +19,7 @@ import (
 	"github.com/opencontainers/runc/libcontainer/cgroups"
 	"github.com/opencontainers/runc/libcontainer/cgroups/fs"
 	"github.com/opencontainers/runc/libcontainer/configs"
+	libcontainerUtils "github.com/opencontainers/runc/libcontainer/utils"
 )
 
 type Manager struct {
@@ -162,10 +163,11 @@ func getIfaceForUnit(unitName string) string {
 
 func (m *Manager) Apply(pid int) error {
 	var (
-		c          = m.Cgroups
-		unitName   = getUnitName(c)
-		slice      = "system.slice"
-		properties []systemdDbus.Property
+		c            = m.Cgroups
+		unitName     = getUnitName(c)
+		parent, name = filepath.Split(c.CgroupsPath)
+		slice        = "system.slice"
+		properties   []systemdDbus.Property
 	)
 
 	if c.Paths != nil {
@@ -185,13 +187,13 @@ func (m *Manager) Apply(pid int) error {
 		return cgroups.EnterPid(m.Paths, pid)
 	}
 
-	if c.Parent != "" {
-		slice = c.Parent
+	if parent != "" {
+		slice = libcontainerUtils.PathClean(parent)
 	}
 
 	properties = append(properties,
 		systemdDbus.PropSlice(slice),
-		systemdDbus.PropDescription("docker container "+c.Name),
+		systemdDbus.PropDescription("docker container "+name),
 		newProp("PIDs", []uint32{uint32(pid)}),
 	)
 
@@ -399,8 +401,8 @@ func getSubsystemPath(c *configs.Cgroup, subsystem string) (string, error) {
 	}
 
 	slice := "system.slice"
-	if c.Parent != "" {
-		slice = c.Parent
+	if dir, _ := filepath.Split(c.CgroupsPath); dir != "" {
+		slice = libcontainerUtils.PathClean(dir)
 	}
 
 	return filepath.Join(mountpoint, initPath, slice, getUnitName(c)), nil
@@ -486,7 +488,8 @@ func (m *Manager) Set(container *configs.Config) error {
 }
 
 func getUnitName(c *configs.Cgroup) string {
-	return fmt.Sprintf("%s-%s.scope", c.ScopePrefix, c.Name)
+	_, name := filepath.Split(c.CgroupsPath)
+	return fmt.Sprintf("%s-%s.scope", c.ScopePrefix, name)
 }
 
 // Atm we can't use the systemd device support because of two missing things:

libcontainer/configs/cgroup_unix.go

@@ -11,15 +11,15 @@ const (
 )
 
 type Cgroup struct {
-	Name string `json:"name"`
-
-	// name of parent cgroup or slice
-	Parent string `json:"parent"`
+	// CgroupsPath specifies the path to cgroups that are created and/or joined by the container.
+	// The path is assumed to be relative to the host system cgroup mountpoint.
+	CgroupsPath string `json:"cgroupsPath"`
 
 	// ScopePrefix decribes prefix for the scope name
 	ScopePrefix string `json:"scope_prefix"`
 
-	// Paths represent the cgroups paths to join
+	// Paths represent the absolute cgroups paths to join.
+	// This takes precedence over CgroupsPath.
 	Paths map[string]string
 
 	// Resources contains various cgroups settings to apply

libcontainer/integration/exec_test.go

@@ -466,6 +466,8 @@ func testFreeze(t *testing.T, systemd bool) {
 	f := factory
 	if systemd {
 		f = systemdFactory
+		_, name := filepath.Split(config.Cgroups.CgroupsPath)
+		config.Cgroups.CgroupsPath = filepath.Join("system.slice", name)
 	}
 
 	container, err := f.Create("test", config)
@@ -521,7 +523,8 @@ func testCpuShares(t *testing.T, systemd bool) {
 
 	config := newTemplateConfig(rootfs)
 	if systemd {
-		config.Cgroups.Parent = "system.slice"
+		_, name := filepath.Split(config.Cgroups.CgroupsPath)
+		config.Cgroups.CgroupsPath = filepath.Join("system.slice", name)
 	}
 	config.Cgroups.Resources.CpuShares = 1
 
@@ -553,7 +556,8 @@ func testPids(t *testing.T, systemd bool) {
 
 	config := newTemplateConfig(rootfs)
 	if systemd {
-		config.Cgroups.Parent = "system.slice"
+		_, name := filepath.Split(config.Cgroups.CgroupsPath)
+		config.Cgroups.CgroupsPath = filepath.Join("system.slice", name)
 	}
 	config.Cgroups.Resources.PidsLimit = -1
 
@@ -621,7 +625,8 @@ func testRunWithKernelMemory(t *testing.T, systemd bool) {
 
 	config := newTemplateConfig(rootfs)
 	if systemd {
-		config.Cgroups.Parent = "system.slice"
+		_, name := filepath.Split(config.Cgroups.CgroupsPath)
+		config.Cgroups.CgroupsPath = filepath.Join("system.slice", name)
 	}
 	config.Cgroups.Resources.KernelMemory = 52428800
 

libcontainer/integration/template_test.go

@@ -46,8 +46,7 @@ func newTemplateConfig(rootfs string) *configs.Config {
 			{Type: configs.NEWNET},
 		}),
 		Cgroups: &configs.Cgroup{
-			Name:   "test",
-			Parent: "integration",
+			CgroupsPath: "integration/test",
 			Resources: &configs.Resources{
 				MemorySwappiness: -1,
 				AllowAllDevices:  false,

libcontainer/integration/utils_test.go

@@ -93,8 +93,8 @@ func copyBusybox(dest string) error {
 
 func newContainer(config *configs.Config) (libcontainer.Container, error) {
 	f := factory
-
-	if config.Cgroups != nil && config.Cgroups.Parent == "system.slice" {
+	dir, _ := filepath.Split(config.Cgroups.CgroupsPath)
+	if config.Cgroups != nil && dir == "system.slice" {
 		f = systemdFactory
 	}
 

spec.go

@@ -18,6 +18,7 @@ import (
 	"github.com/opencontainers/runc/libcontainer/cgroups"
 	"github.com/opencontainers/runc/libcontainer/configs"
 	"github.com/opencontainers/runc/libcontainer/seccomp"
+	libcontainerUtils "github.com/opencontainers/runc/libcontainer/utils"
 	"github.com/opencontainers/specs"
 )
 
@@ -449,14 +450,23 @@ func createLibcontainerMount(cwd, dest string, m specs.Mount) *configs.Mount {
 }
 
 func createCgroupConfig(name string, spec *specs.LinuxRuntimeSpec, devices []*configs.Device) (*configs.Cgroup, error) {
-	myCgroupPath, err := cgroups.GetThisCgroupDir("devices")
-	if err != nil {
-		return nil, err
+	var (
+		err          error
+		myCgroupPath string
+	)
+
+	if spec.Linux.CgroupsPath != "" {
+		myCgroupPath = libcontainerUtils.PathClean(spec.Linux.CgroupsPath)
+	} else {
+		myCgroupPath, err = cgroups.GetThisCgroupDir("devices")
+		if err != nil {
+			return nil, err
+		}
 	}
+
 	c := &configs.Cgroup{
-		Name:      name,
-		Parent:    myCgroupPath,
-		Resources: &configs.Resources{},
+		CgroupsPath: filepath.Join(myCgroupPath, name),
+		Resources:   &configs.Resources{},
 	}
 	c.Resources.AllowedDevices = append(devices, allowedDevices...)
 	r := spec.Linux.Resources