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Add checks in Create and Update Cgroup methods

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This commit is contained in:
Buddha Prakash 2016-07-06 15:08:01 -07:00
parent c0b67b62b2
commit dcfff45ab7
4 changed files with 107 additions and 68 deletions
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129
pkg/kubelet/cm/cgroup_manager_linux.go
View File

@ -18,7 +18,10 @@ package cm
import (
"fmt"
"path"
libcontainercgroups "github.com/opencontainers/runc/libcontainer/cgroups"
cgroupfs "github.com/opencontainers/runc/libcontainer/cgroups/fs"
libcontainerconfigs "github.com/opencontainers/runc/libcontainer/configs"
)
@ -42,17 +45,46 @@ func NewCgroupManager(cs *cgroupSubsystems) CgroupManager {
}
}
// Exists checks if all subsystem cgroups already exist
func (m *cgroupManagerImpl) Exists(name string) bool {
// Get map of all cgroup paths on the system for the particular cgroup
cgroupPaths := make(map[string]string, len(m.subsystems.mountPoints))
for key, val := range m.subsystems.mountPoints {
cgroupPaths[key] = path.Join(val, name)
}
// If even one cgroup doesn't exist we go on to create it
// @TODO(dubstack) We skip check for systemd until we update
// libcontainer in vendor
for key, path := range cgroupPaths {
if key != "systemd" && !libcontainercgroups.PathExists(path) {
return false
}
}
return true
}
// Destroy destroys the specified cgroup
func (m *cgroupManagerImpl) Destroy(cgroupConfig *CgroupConfig) error {
//cgroup name
name := cgroupConfig.Name
// get the fscgroup Manager with the specified cgroup configuration
fsCgroupManager, err := getLibcontainerCgroupManager(cgroupConfig, m.subsystems)
if err != nil {
return fmt.Errorf("Unable to destroy cgroup paths for cgroup %v : %v", name, err)
// Get map of all cgroup paths on the system for the particular cgroup
cgroupPaths := make(map[string]string, len(m.subsystems.mountPoints))
for key, val := range m.subsystems.mountPoints {
cgroupPaths[key] = path.Join(val, name)
}
// Initialize libcontainer's cgroup config
libcontainerCgroupConfig := &libcontainerconfigs.Cgroup{
Name: path.Base(name),
Parent: path.Dir(name),
}
fsCgroupManager := cgroupfs.Manager{
Cgroups: libcontainerCgroupConfig,
Paths: cgroupPaths,
}
// Delete cgroups using libcontainers Managers Destroy() method
if err := fsCgroupManager.Destroy(); err != nil {
return fmt.Errorf("Unable to destroy cgroup paths for cgroup %v : %v", name, err)
@ -60,41 +92,86 @@ func (m *cgroupManagerImpl) Destroy(cgroupConfig *CgroupConfig) error {
return nil
}
type subsystem interface {
// Name returns the name of the subsystem.
Name() string
// Set the cgroup represented by cgroup.
Set(path string, cgroup *libcontainerconfigs.Cgroup) error
}
// Cgroup subsystems we currently support
var supportedSubsystems []subsystem = []subsystem{
&cgroupfs.MemoryGroup{},
&cgroupfs.CpuGroup{},
}
// setSupportedSubsytems sets cgroup resource limits only on the supported
// subsytems. ie. cpu and memory. We don't use libcontainer's cgroup/fs/Set()
// method as it dosn't allow us to skip updates on the devices cgroup
// Allowing or denying all devices by writing 'a' to devices.allow or devices.deny is
// not possible once the device cgroups has children. Once the pod level cgroup are
// created under the QOS level cgroup we cannot update the QOS level device cgroup.
// We would like to skip setting any values on the device cgroup in this case
// but this is not possible with libcontainers Set() method
// See https://github.com/opencontainers/runc/issues/932
func setSupportedSubsytems(cgroupConfig *libcontainerconfigs.Cgroup) error {
for _, sys := range supportedSubsystems {
if _, ok := cgroupConfig.Paths[sys.Name()]; !ok {
return fmt.Errorf("Failed to find subsytem mount for subsytem")
}
if err := sys.Set(cgroupConfig.Paths[sys.Name()], cgroupConfig); err != nil {
return fmt.Errorf("Failed to set config for supported subsystems : %v", err)
}
}
return nil
}
// Update updates the cgroup with the specified Cgroup Configuration
func (m *cgroupManagerImpl) Update(cgroupConfig *CgroupConfig) error {
//cgroup name
name := cgroupConfig.Name
// get the fscgroup Manager with the specified cgroup configuration
fsCgroupManager, err := getLibcontainerCgroupManager(cgroupConfig, m.subsystems)
if err != nil {
return fmt.Errorf("Failed to update cgroup for %v : %v", name, err)
// Extract the cgroup resource parameters
resourceConfig := cgroupConfig.ResourceParameters
resources := &libcontainerconfigs.Resources{}
if resourceConfig.Memory != nil {
resources.Memory = *resourceConfig.Memory
}
// get config object for passing to Set()
config := &libcontainerconfigs.Config{
Cgroups: fsCgroupManager.Cgroups,
if resourceConfig.CpuShares != nil {
resources.CpuShares = *resourceConfig.CpuShares
}
if resourceConfig.CpuQuota != nil {
resources.CpuQuota = *resourceConfig.CpuQuota
}
// Update cgroup configuration using libcontainers Managers Set() method
if err := fsCgroupManager.Set(config); err != nil {
return fmt.Errorf("Failed to update cgroup for %v: %v", name, err)
// Initialize libcontainer's cgroup config
libcontainerCgroupConfig := &libcontainerconfigs.Cgroup{
Name: path.Base(name),
Parent: path.Dir(name),
Resources: resources,
}
if err := setSupportedSubsytems(libcontainerCgroupConfig); err != nil {
return fmt.Errorf("Failed to set supported cgroup subsystems for cgroup %v: %v", name, err)
}
return nil
}
// Create creates the specified cgroup
func (m *cgroupManagerImpl) Create(cgroupConfig *CgroupConfig) error {
//cgroup name
// get cgroup name
name := cgroupConfig.Name
// get the fscgroup Manager with the specified cgroup configuration
fsCgroupManager, err := getLibcontainerCgroupManager(cgroupConfig, m.subsystems)
if err != nil {
return fmt.Errorf("Failed to create cgroup for %v : %v", name, err)
// Initialize libcontainer's cgroup config
libcontainerCgroupConfig := &libcontainerconfigs.Cgroup{
Name: path.Base(name),
Parent: path.Dir(name),
Resources: &libcontainerconfigs.Resources{},
}
// get config object for passing to libcontainer's Set() method
config := &libcontainerconfigs.Config{
Cgroups: fsCgroupManager.Cgroups,
// get the fscgroup Manager with the specified cgroup configuration
fsCgroupManager := &cgroupfs.Manager{
Cgroups: libcontainerCgroupConfig,
}
//Apply(0) is a hack to create the cgroup directories for each resource
// subsystem. The function [cgroups.Manager.apply()] applies cgroup
@ -103,11 +180,7 @@ func (m *cgroupManagerImpl) Create(cgroupConfig *CgroupConfig) error {
// in the tasks file. We use the function to create all the required
// cgroup files but not attach any "real" pid to the cgroup.
if err := fsCgroupManager.Apply(0); err != nil {
return fmt.Errorf("Failed to create cgroup for %v: %v", name, err)
}
// Update cgroup configuration using libcontainers Managers Set() method
if err := fsCgroupManager.Set(config); err != nil {
return fmt.Errorf("Failed to create cgroup for %v: %v", name, err)
return fmt.Errorf("Failed to apply cgroup config for %v: %v", name, err)
}
return nil
}

4
pkg/kubelet/cm/cgroup_manager_unsupported.go
View File

@ -29,6 +29,10 @@ func NewCgroupManager(_ interface{}) CgroupManager {
return &unsupportedCgroupManager{}
}
func (m *unsupportedCgroupManager) Exists(_ string) bool {
return false
}
func (m *unsupportedCgroupManager) Destroy(_ *CgroupConfig) error {
return nil
}

40
pkg/kubelet/cm/helpers_linux.go
View File

@ -18,11 +18,8 @@ package cm
import (
"fmt"
"path"
libcontainercgroups "github.com/opencontainers/runc/libcontainer/cgroups"
cgroupfs "github.com/opencontainers/runc/libcontainer/cgroups/fs"
libcontainerconfigs "github.com/opencontainers/runc/libcontainer/configs"
)
// cgroupSubsystems holds information about the mounted cgroup subsytems
@ -59,40 +56,3 @@ func getCgroupSubsystems() (*cgroupSubsystems, error) {
mountPoints: mountPoints,
}, nil
}
// getLibcontainerCgroupManager returns libcontainer's cgroups manager
// object with the specified cgroup configuration
func getLibcontainerCgroupManager(cgroupConfig *CgroupConfig, subsystems *cgroupSubsystems) (*cgroupfs.Manager, error) {
// get cgroup name
name := cgroupConfig.Name
// Get map of all cgroup paths on the system for the particular cgroup
cgroupPaths := make(map[string]string, len(subsystems.mountPoints))
for key, val := range subsystems.mountPoints {
cgroupPaths[key] = path.Join(val, name)
}
// Extract the cgroup resource parameters
resourceConfig := cgroupConfig.ResourceParameters
resources := &libcontainerconfigs.Resources{}
resources.AllowAllDevices = true
if resourceConfig.Memory != nil {
resources.Memory = *resourceConfig.Memory
}
if resourceConfig.CpuShares != nil {
resources.CpuShares = *resourceConfig.CpuShares
}
if resourceConfig.CpuQuota != nil {
resources.CpuQuota = *resourceConfig.CpuQuota
}
// Initialize libcontainer's cgroup config
libcontainerCgroupConfig := &libcontainerconfigs.Cgroup{
Name: path.Base(name),
Parent: path.Dir(name),
Resources: resources,
}
return &cgroupfs.Manager{
Cgroups: libcontainerCgroupConfig,
Paths: cgroupPaths,
}, nil
}

2
pkg/kubelet/cm/types.go
View File

@ -53,4 +53,6 @@ type CgroupManager interface {
Destroy(*CgroupConfig) error
// Update cgroup configuration.
Update(*CgroupConfig) error
// Exists checks if the cgroup already exists
Exists(string) bool
}