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Refactory cgroups into general pkg

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Docker-DCO-1.1-Signed-off-by: Michael Crosby <michael@crosbymichael.com> (github: crosbymichael)
This commit is contained in:
Michael Crosby 2014-02-20 15:48:48 -08:00
parent b90aaf6828
commit 1cecb00003
4 changed files with 124 additions and 104 deletions
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61
cgroups/cgroups.go
View file

@ -5,10 +5,23 @@ import (
"fmt"
"github.com/dotcloud/docker/pkg/mount"
"io"
"io/ioutil"
"os"
"path/filepath"
"strconv"
"strings"
)
type Cgroup struct {
Name string `json:"name,omitempty"`
Parent string `json:"parent,omitempty"`
DeviceAccess bool `json:"device_access,omitempty"` // name of parent cgroup or slice
Memory int64 `json:"memory,omitempty"` // Memory limit (in bytes)
MemorySwap int64 `json:"memory_swap,omitempty"` // Total memory usage (memory + swap); set `-1' to disable swap
CpuShares int64 `json:"cpu_shares,omitempty"` // CPU shares (relative weight vs. other containers)
}
// https://www.kernel.org/doc/Documentation/cgroups/cgroups.txt
func FindCgroupMountpoint(subsystem string) (string, error) {
mounts, err := mount.GetMounts()
@ -25,7 +38,6 @@ func FindCgroupMountpoint(subsystem string) (string, error) {
}
}
}
return "", fmt.Errorf("cgroup mountpoint not found for %s", subsystem)
}
@ -50,9 +62,50 @@ func GetInitCgroupDir(subsystem string) (string, error) {
return parseCgroupFile(subsystem, f)
}
func (c *Cgroup) Path(root, subsystem string) (string, error) {
cgroup := c.Name
if c.Parent != "" {
cgroup = filepath.Join(c.Parent, cgroup)
}
initPath, err := GetInitCgroupDir(subsystem)
if err != nil {
return "", err
}
return filepath.Join(root, subsystem, initPath, cgroup), nil
}
func (c *Cgroup) Join(root, subsystem string, pid int) (string, error) {
path, err := c.Path(root, subsystem)
if err != nil {
return "", err
}
if err := os.MkdirAll(path, 0755); err != nil && !os.IsExist(err) {
return "", err
}
if err := writeFile(path, "tasks", strconv.Itoa(pid)); err != nil {
return "", err
}
return path, nil
}
func (c *Cgroup) Cleanup(root string) error {
get := func(subsystem string) string {
path, _ := c.Path(root, subsystem)
return path
}
for _, path := range []string{
get("memory"),
get("devices"),
get("cpu"),
} {
os.RemoveAll(path)
}
return nil
}
func parseCgroupFile(subsystem string, r io.Reader) (string, error) {
s := bufio.NewScanner(r)
for s.Scan() {
if err := s.Err(); err != nil {
return "", err
@ -67,3 +120,7 @@ func parseCgroupFile(subsystem string, r io.Reader) (string, error) {
}
return "", fmt.Errorf("cgroup '%s' not found in /proc/self/cgroup", subsystem)
}
func writeFile(dir, file, data string) error {
return ioutil.WriteFile(filepath.Join(dir, file), []byte(data), 0700)
}

131
libcontainer/cgroup/cgroup.go
View file

@ -10,71 +10,46 @@ import (
"strconv"
)
// We have two implementation of cgroups support, one is based on
// systemd and the dbus api, and one is based on raw cgroup fs operations
// following the pre-single-writer model docs at:
// http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups/
const (
cgroupRoot = "/sys/fs/cgroup"
)
func useSystemd() bool {
return false
}
func applyCgroupSystemd(container *libcontainer.Container, pid int) error {
return fmt.Errorf("not supported yet")
}
func writeFile(dir, file, data string) error {
return ioutil.WriteFile(filepath.Join(dir, file), []byte(data), 0700)
}
func getCgroup(subsystem string, container *libcontainer.Container) (string, error) {
cgroup := container.CgroupName
if container.CgroupParent != "" {
cgroup = filepath.Join(container.CgroupParent, cgroup)
func ApplyCgroup(container *libcontainer.Container, pid int) (err error) {
if container.Cgroups == nil {
return nil
}
initPath, err := cgroups.GetInitCgroupDir(subsystem)
// We have two implementation of cgroups support, one is based on
// systemd and the dbus api, and one is based on raw cgroup fs operations
// following the pre-single-writer model docs at:
// http://www.freedesktop.org/wiki/Software/systemd/PaxControlGroups/
//
// we can pick any subsystem to find the root
cgroupRoot, err := cgroups.FindCgroupMountpoint("memory")
if err != nil {
return "", err
return err
}
path := filepath.Join(cgroupRoot, subsystem, initPath, cgroup)
return path, nil
}
func joinCgroup(subsystem string, container *libcontainer.Container, pid int) (string, error) {
path, err := getCgroup(subsystem, container)
if err != nil {
return "", err
}
if err := os.MkdirAll(path, 0755); err != nil && !os.IsExist(err) {
return "", err
}
if err := writeFile(path, "tasks", strconv.Itoa(pid)); err != nil {
return "", err
}
return path, nil
}
func applyCgroupRaw(container *libcontainer.Container, pid int) (retErr error) {
cgroupRoot = filepath.Dir(cgroupRoot)
if _, err := os.Stat(cgroupRoot); err != nil {
return fmt.Errorf("cgroups fs not found")
}
if err := setupDevices(container, cgroupRoot, pid); err != nil {
return err
}
if err := setupMemory(container, cgroupRoot, pid); err != nil {
return err
}
if err := setupCpu(container, cgroupRoot, pid); err != nil {
return err
}
return nil
}
if !container.DeviceAccess {
dir, err := joinCgroup("devices", container, pid)
func setupDevices(container *libcontainer.Container, cgroupRoot string, pid int) (err error) {
if !container.Cgroups.DeviceAccess {
dir, err := container.Cgroups.Join(cgroupRoot, "devices", pid)
if err != nil {
return err
}
defer func() {
if retErr != nil {
if err != nil {
os.RemoveAll(dir)
}
}()
@ -113,65 +88,53 @@ func applyCgroupRaw(container *libcontainer.Container, pid int) (retErr error) {
}
}
}
return nil
}
if container.Memory != 0 || container.MemorySwap != 0 {
dir, err := joinCgroup("memory", container, pid)
func setupMemory(container *libcontainer.Container, cgroupRoot string, pid int) (err error) {
if container.Cgroups.Memory != 0 || container.Cgroups.MemorySwap != 0 {
dir, err := container.Cgroups.Join(cgroupRoot, "memory", pid)
if err != nil {
return err
}
defer func() {
if retErr != nil {
if err != nil {
os.RemoveAll(dir)
}
}()
if container.Memory != 0 {
if err := writeFile(dir, "memory.limit_in_bytes", strconv.FormatInt(container.Memory, 10)); err != nil {
if container.Cgroups.Memory != 0 {
if err := writeFile(dir, "memory.limit_in_bytes", strconv.FormatInt(container.Cgroups.Memory, 10)); err != nil {
return err
}
if err := writeFile(dir, "memory.soft_limit_in_bytes", strconv.FormatInt(container.Memory, 10)); err != nil {
if err := writeFile(dir, "memory.soft_limit_in_bytes", strconv.FormatInt(container.Cgroups.Memory, 10)); err != nil {
return err
}
}
if container.MemorySwap != 0 {
if err := writeFile(dir, "memory.memsw.limit_in_bytes", strconv.FormatInt(container.MemorySwap, 10)); err != nil {
if container.Cgroups.MemorySwap != 0 {
if err := writeFile(dir, "memory.memsw.limit_in_bytes", strconv.FormatInt(container.Cgroups.MemorySwap, 10)); err != nil {
return err
}
}
}
return nil
}
func setupCpu(container *libcontainer.Container, cgroupRoot string, pid int) (err error) {
// We always want to join the cpu group, to allow fair cpu scheduling
// on a container basis
dir, err := joinCgroup("cpu", container, pid)
dir, err := container.Cgroups.Join(cgroupRoot, "cpu", pid)
if err != nil {
return err
}
if container.CpuShares != 0 {
if err := writeFile(dir, "cpu.shares", strconv.FormatInt(container.CpuShares, 10)); err != nil {
if container.Cgroups.CpuShares != 0 {
if err := writeFile(dir, "cpu.shares", strconv.FormatInt(container.Cgroups.CpuShares, 10)); err != nil {
return err
}
}
return nil
}
func CleanupCgroup(container *libcontainer.Container) error {
path, _ := getCgroup("memory", container)
os.RemoveAll(path)
path, _ = getCgroup("devices", container)
os.RemoveAll(path)
path, _ = getCgroup("cpu", container)
os.RemoveAll(path)
return nil
}
func ApplyCgroup(container *libcontainer.Container, pid int) error {
if container.CgroupName == "" {
return nil
}
if useSystemd() {
return applyCgroupSystemd(container, pid)
} else {
return applyCgroupRaw(container, pid)
}
func writeFile(dir, file, data string) error {
return ioutil.WriteFile(filepath.Join(dir, file), []byte(data), 0700)
}

28
libcontainer/container.go
View file

@ -1,23 +1,21 @@
package libcontainer
import (
"github.com/dotcloud/docker/pkg/cgroups"
)
// Container defines configuration options for how a
// container is setup inside a directory and how a process should be executed
type Container struct {
Hostname string `json:"hostname,omitempty"` // hostname
ReadonlyFs bool `json:"readonly_fs,omitempty"` // set the containers rootfs as readonly
User string `json:"user,omitempty"` // user to execute the process as
WorkingDir string `json:"working_dir,omitempty"` // current working directory
Env []string `json:"environment,omitempty"` // environment to set
Namespaces Namespaces `json:"namespaces,omitempty"` // namespaces to apply
Capabilities Capabilities `json:"capabilities,omitempty"` // capabilities to drop
Network *Network `json:"network,omitempty"` // nil for host's network stack
CgroupName string `json:"cgroup_name,omitempty"` // name of cgroup
CgroupParent string `json:"cgroup_parent,omitempty"` // name of parent cgroup or slice
DeviceAccess bool `json:"device_access,omitempty"` // name of parent cgroup or slice
Memory int64 `json:"memory,omitempty"` // Memory limit (in bytes)
MemorySwap int64 `json:"memory_swap,omitempty"` // Total memory usage (memory + swap); set `-1' to disable swap
CpuShares int64 `json:"cpu_shares,omitempty"` // CPU shares (relative weight vs. other containers)
Hostname string `json:"hostname,omitempty"` // hostname
ReadonlyFs bool `json:"readonly_fs,omitempty"` // set the containers rootfs as readonly
User string `json:"user,omitempty"` // user to execute the process as
WorkingDir string `json:"working_dir,omitempty"` // current working directory
Env []string `json:"environment,omitempty"` // environment to set
Namespaces Namespaces `json:"namespaces,omitempty"` // namespaces to apply
Capabilities Capabilities `json:"capabilities,omitempty"` // capabilities to drop
Network *Network `json:"network,omitempty"` // nil for host's network stack
Cgroups *cgroups.Cgroup `json:"cgroups,omitempty"`
}
// Network defines configuration for a container's networking stack

8
libcontainer/container.json
View file

@ -35,7 +35,9 @@
"bridge": "docker0",
"mtu": 1500
},
"cgroup_name": "docker-koye",
"cgroup_parent": "docker",
"memory": 524800
"cgroups": {
"name": "docker-koye",
"parent": "docker",
"memory": 524800
}
}