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Refactor network creation and initialization into strategies

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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 2014-02-21 22:20:15 -08:00
parent cda4f27f57
commit 609c298810
7 changed files with 211 additions and 107 deletions
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9
libcontainer/README.md
View file

@ -45,12 +45,17 @@ Sample `container.json` file:
"AUDIT_WRITE",
"AUDIT_CONTROL",
"MAC_OVERRIDE",
"MAC_ADMIN"
"MAC_ADMIN",
"NET_ADMIN"
],
"network": {
"type": "veth",
"context": {
"bridge": "docker0",
"prefix": "dock"
},
"address": "172.17.0.100/16",
"gateway": "172.17.42.1",
"bridge": "docker0",
"mtu": 1500
},
"cgroups": {

13
libcontainer/container.go
View file

@ -4,6 +4,10 @@ import (
"github.com/dotcloud/docker/pkg/cgroups"
)
// Context is a generic key value pair that allows
// arbatrary data to be sent
type Context map[string]string
// Container defines configuration options for how a
// container is setup inside a directory and how a process should be executed
type Container struct {
@ -24,8 +28,9 @@ type Container struct {
// The network configuration can be omited from a container causing the
// container to be setup with the host's networking stack
type Network struct {
Address string `json:"address,omitempty"`
Gateway string `json:"gateway,omitempty"`
Bridge string `json:"bridge,omitempty"`
Mtu int `json:"mtu,omitempty"`
Type string `json:"type,omitempty"` // type of networking to setup i.e. veth, macvlan, etc
Context Context `json:"context,omitempty"` // generic context for type specific networking options
Address string `json:"address,omitempty"`
Gateway string `json:"gateway,omitempty"`
Mtu int `json:"mtu,omitempty"`
}

9
libcontainer/container.json
View file

@ -28,12 +28,17 @@
"AUDIT_WRITE",
"AUDIT_CONTROL",
"MAC_OVERRIDE",
"MAC_ADMIN"
"MAC_ADMIN",
"NET_ADMIN"
],
"network": {
"type": "veth",
"context": {
"bridge": "docker0",
"prefix": "dock"
},
"address": "172.17.0.100/16",
"gateway": "172.17.42.1",
"bridge": "docker0",
"mtu": 1500
},
"cgroups": {

32
libcontainer/network/strategy.go Normal file
View file

@ -0,0 +1,32 @@
package network
import (
"errors"
"github.com/dotcloud/docker/pkg/libcontainer"
)
var (
ErrNotValidStrategyType = errors.New("not a valid network strategy type")
)
var strategies = map[string]NetworkStrategy{
"veth": &Veth{},
}
// NetworkStrategy represends a specific network configuration for
// a containers networking stack
type NetworkStrategy interface {
Create(*libcontainer.Network, int) (libcontainer.Context, error)
Initialize(*libcontainer.Network, libcontainer.Context) error
}
// GetStrategy returns the specific network strategy for the
// provided type. If no strategy is registered for the type an
// ErrNotValidStrategyType is returned.
func GetStrategy(tpe string) (NetworkStrategy, error) {
s, exists := strategies[tpe]
if !exists {
return nil, ErrNotValidStrategyType
}
return s, nil
}

103
libcontainer/network/veth.go Normal file
View file

@ -0,0 +1,103 @@
package network
import (
"fmt"
"github.com/dotcloud/docker/pkg/libcontainer"
"github.com/dotcloud/docker/pkg/libcontainer/utils"
"log"
)
type Veth struct {
}
func (v *Veth) Create(n *libcontainer.Network, nspid int) (libcontainer.Context, error) {
log.Printf("creating veth network")
var (
bridge string
prefix string
exists bool
)
if bridge, exists = n.Context["bridge"]; !exists {
return nil, fmt.Errorf("bridge does not exist in network context")
}
if prefix, exists = n.Context["prefix"]; !exists {
return nil, fmt.Errorf("veth prefix does not exist in network context")
}
name1, name2, err := createVethPair(prefix)
if err != nil {
return nil, err
}
context := libcontainer.Context{
"vethHost": name1,
"vethChild": name2,
}
log.Printf("veth pair created %s <> %s", name1, name2)
if err := SetInterfaceMaster(name1, bridge); err != nil {
return context, err
}
if err := SetMtu(name1, n.Mtu); err != nil {
return context, err
}
if err := InterfaceUp(name1); err != nil {
return context, err
}
log.Printf("setting %s inside %d namespace", name2, nspid)
if err := SetInterfaceInNamespacePid(name2, nspid); err != nil {
return context, err
}
return context, nil
}
func (v *Veth) Initialize(config *libcontainer.Network, context libcontainer.Context) error {
var (
vethChild string
exists bool
)
if vethChild, exists = context["vethChild"]; !exists {
return fmt.Errorf("vethChild does not exist in network context")
}
if err := InterfaceDown(vethChild); err != nil {
return fmt.Errorf("interface down %s %s", vethChild, err)
}
if err := ChangeInterfaceName(vethChild, "eth0"); err != nil {
return fmt.Errorf("change %s to eth0 %s", vethChild, err)
}
if err := SetInterfaceIp("eth0", config.Address); err != nil {
return fmt.Errorf("set eth0 ip %s", err)
}
if err := SetMtu("eth0", config.Mtu); err != nil {
return fmt.Errorf("set eth0 mtu to %d %s", config.Mtu, err)
}
if err := InterfaceUp("eth0"); err != nil {
return fmt.Errorf("eth0 up %s", err)
}
if err := SetMtu("lo", config.Mtu); err != nil {
return fmt.Errorf("set lo mtu to %d %s", config.Mtu, err)
}
if err := InterfaceUp("lo"); err != nil {
return fmt.Errorf("lo up %s", err)
}
if config.Gateway != "" {
if err := SetDefaultGateway(config.Gateway); err != nil {
return fmt.Errorf("set gateway to %s %s", config.Gateway, err)
}
}
return nil
}
// createVethPair will automatically generage two random names for
// the veth pair and ensure that they have been created
func createVethPair(prefix string) (name1 string, name2 string, err error) {
name1, err = utils.GenerateRandomName(prefix, 4)
if err != nil {
return
}
name2, err = utils.GenerateRandomName(prefix, 4)
if err != nil {
return
}
if err = CreateVethPair(name1, name2); err != nil {
return
}
return
}

97
libcontainer/nsinit/exec.go
View file

@ -3,10 +3,10 @@
package nsinit
import (
"encoding/json"
"fmt"
"github.com/dotcloud/docker/pkg/libcontainer"
"github.com/dotcloud/docker/pkg/libcontainer/network"
"github.com/dotcloud/docker/pkg/libcontainer/utils"
"github.com/dotcloud/docker/pkg/system"
"github.com/dotcloud/docker/pkg/term"
"io"
@ -19,11 +19,11 @@ import (
// Exec performes setup outside of a namespace so that a container can be
// executed. Exec is a high level function for working with container namespaces.
func Exec(container *libcontainer.Container, stdin io.Reader, stdout, stderr io.Writer, master *os.File, logFile string, args []string) (int, error) {
func Exec(container *libcontainer.Container, stdin io.Reader, stdout, stderr io.Writer,
master *os.File, logFile string, args []string) (int, error) {
var (
console string
err error
console string
err error
inPipe io.WriteCloser
outPipe, errPipe io.ReadCloser
)
@ -46,7 +46,7 @@ func Exec(container *libcontainer.Container, stdin io.Reader, stdout, stderr io.
command := CreateCommand(container, console, logFile, r.Fd(), args)
if !container.Tty {
log.Printf("opening pipes on command")
log.Printf("opening std pipes")
if inPipe, err = command.StdinPipe(); err != nil {
return -1, err
}
@ -78,15 +78,9 @@ func Exec(container *libcontainer.Container, stdin io.Reader, stdout, stderr io.
return -1, err
}
}
if container.Network != nil {
log.Printf("creating veth pair")
vethPair, err := InitializeContainerVeth(container.Network.Bridge, container.Network.Mtu, command.Process.Pid)
if err != nil {
return -1, err
}
log.Printf("sending %s as veth pair name", vethPair)
SendVethName(w, vethPair)
if err := InitializeNetworking(container, command.Process.Pid, w); err != nil {
command.Process.Kill()
return -1, err
}
// Sync with child
@ -104,7 +98,7 @@ func Exec(container *libcontainer.Container, stdin io.Reader, stdout, stderr io.
command.Process.Kill()
return -1, err
}
defer term.RestoreTerminal(uintptr(syscall.Stdin), state)
defer term.RestoreTerminal(os.Stdin.Fd(), state)
} else {
log.Printf("starting copy for std pipes")
go func() {
@ -125,39 +119,34 @@ func Exec(container *libcontainer.Container, stdin io.Reader, stdout, stderr io.
return command.ProcessState.Sys().(syscall.WaitStatus).ExitStatus(), nil
}
// SendVethName writes the veth pair name to the child's stdin then closes the
// pipe so that the child stops waiting for more data
func SendVethName(pipe io.Writer, name string) {
fmt.Fprint(pipe, name)
func InitializeNetworking(container *libcontainer.Container, nspid int, pipe io.Writer) error {
if container.Network != nil {
log.Printf("creating host network configuration type %s", container.Network.Type)
strategy, err := network.GetStrategy(container.Network.Type)
if err != nil {
return err
}
networkContext, err := strategy.Create(container.Network, nspid)
if err != nil {
return err
}
log.Printf("sending %v as network context", networkContext)
if err := SendContext(pipe, networkContext); err != nil {
return err
}
}
return nil
}
// initializeContainerVeth will create a veth pair and setup the host's
// side of the pair by setting the specified bridge as the master and bringing
// up the interface.
//
// Then will with set the other side of the veth pair into the container's namespaced
// using the pid and returns the veth's interface name to provide to the container to
// finish setting up the interface inside the namespace
func InitializeContainerVeth(bridge string, mtu, nspid int) (string, error) {
name1, name2, err := createVethPair()
// SendContext writes the veth pair name to the child's stdin then closes the
// pipe so that the child stops waiting for more data
func SendContext(pipe io.Writer, context libcontainer.Context) error {
data, err := json.Marshal(context)
if err != nil {
return "", err
return err
}
log.Printf("veth pair created %s <> %s", name1, name2)
if err := network.SetInterfaceMaster(name1, bridge); err != nil {
return "", err
}
if err := network.SetMtu(name1, mtu); err != nil {
return "", err
}
if err := network.InterfaceUp(name1); err != nil {
return "", err
}
log.Printf("setting %s inside %d namespace", name2, nspid)
if err := network.SetInterfaceInNamespacePid(name2, nspid); err != nil {
return "", err
}
return name2, nil
pipe.Write(data)
return nil
}
// SetupWindow gets the parent window size and sets the master
@ -190,29 +179,13 @@ func CreateMasterAndConsole() (*os.File, string, error) {
return master, console, nil
}
// createVethPair will automatically generage two random names for
// the veth pair and ensure that they have been created
func createVethPair() (name1 string, name2 string, err error) {
name1, err = utils.GenerateRandomName("dock", 4)
if err != nil {
return
}
name2, err = utils.GenerateRandomName("dock", 4)
if err != nil {
return
}
if err = network.CreateVethPair(name1, name2); err != nil {
return
}
return
}
// writePidFile writes the namespaced processes pid to .nspid in the rootfs for the container
func writePidFile(command *exec.Cmd) error {
return ioutil.WriteFile(".nspid", []byte(fmt.Sprint(command.Process.Pid)), 0655)
}
func deletePidFile() error {
log.Printf("removing .nspid file")
return os.Remove(".nspid")
}

55
libcontainer/nsinit/init.go
View file

@ -3,6 +3,7 @@
package nsinit
import (
"encoding/json"
"fmt"
"github.com/dotcloud/docker/pkg/libcontainer"
"github.com/dotcloud/docker/pkg/libcontainer/capabilities"
@ -27,13 +28,10 @@ func Init(container *libcontainer.Container, uncleanRootfs, console string, pipe
log.Printf("initializing namespace at %s", rootfs)
// We always read this as it is a way to sync with the parent as well
tempVethName, err := getVethName(pipe)
context, err := GetContextFromParent(pipe)
if err != nil {
return err
}
if tempVethName != "" {
log.Printf("received veth name %s", tempVethName)
}
if console != "" {
log.Printf("setting up console for %s", console)
// close pipes so that we can replace it with the pty
@ -62,7 +60,7 @@ func Init(container *libcontainer.Container, uncleanRootfs, console string, pipe
if err := setupNewMountNamespace(rootfs, console, container.ReadonlyFs); err != nil {
return fmt.Errorf("setup mount namespace %s", err)
}
if err := setupVethNetwork(container.Network, tempVethName); err != nil {
if err := setupNetwork(container.Network, context); err != nil {
return fmt.Errorf("setup networking %s", err)
}
if err := system.Sethostname(container.Hostname); err != nil {
@ -145,46 +143,29 @@ func openTerminal(name string, flag int) (*os.File, error) {
// setupVethNetwork uses the Network config if it is not nil to initialize
// the new veth interface inside the container for use by changing the name to eth0
// setting the MTU and IP address along with the default gateway
func setupVethNetwork(config *libcontainer.Network, tempVethName string) error {
func setupNetwork(config *libcontainer.Network, context libcontainer.Context) error {
if config != nil {
if err := network.InterfaceDown(tempVethName); err != nil {
return fmt.Errorf("interface down %s %s", tempVethName, err)
}
if err := network.ChangeInterfaceName(tempVethName, "eth0"); err != nil {
return fmt.Errorf("change %s to eth0 %s", tempVethName, err)
}
if err := network.SetInterfaceIp("eth0", config.Address); err != nil {
return fmt.Errorf("set eth0 ip %s", err)
}
if err := network.SetMtu("eth0", config.Mtu); err != nil {
return fmt.Errorf("set eth0 mtu to %d %s", config.Mtu, err)
}
if err := network.InterfaceUp("eth0"); err != nil {
return fmt.Errorf("eth0 up %s", err)
}
if err := network.SetMtu("lo", config.Mtu); err != nil {
return fmt.Errorf("set lo mtu to %d %s", config.Mtu, err)
}
if err := network.InterfaceUp("lo"); err != nil {
return fmt.Errorf("lo up %s", err)
}
if config.Gateway != "" {
if err := network.SetDefaultGateway(config.Gateway); err != nil {
return fmt.Errorf("set gateway to %s %s", config.Gateway, err)
}
strategy, err := network.GetStrategy(config.Type)
if err != nil {
return err
}
return strategy.Initialize(config, context)
}
return nil
}
// getVethName reads from Stdin the temp veth name
// sent by the parent processes after the veth pair
// has been created and setup
func getVethName(pipe io.ReadCloser) (string, error) {
func GetContextFromParent(pipe io.ReadCloser) (libcontainer.Context, error) {
defer pipe.Close()
data, err := ioutil.ReadAll(pipe)
if err != nil {
return "", fmt.Errorf("error reading from stdin %s", err)
return nil, fmt.Errorf("error reading from stdin %s", err)
}
return string(data), nil
var context libcontainer.Context
if len(data) > 0 {
if err := json.Unmarshal(data, &context); err != nil {
return nil, err
}
log.Printf("received context %v", context)
}
return context, nil
}