crosbymichael

Links - Spec

Links are a way of expressing a relationship between one container and another. When you link a container, you create a parent/child relationship between the two. As a side effect links also allow you to name containers and reference them by name. Containers can be references by more than one name.

Breaking changes

This the new link feature we will be disabling intercontainer communication by default. Containers will not be able to communicate with each other over the docker0 bridge without having a link to that container. Even with a link, a parent can only communicate to the ports exposed by the child and nothing more.

Initially links will be expressed by injecting the child's data into the parent's environment accessible via namespaced variables:

crosbymichael

package main

import (
	"encoding/json"
	"io"
	"log"
	"net/http"
)

type Event struct {

crosbymichael

package main

import (
	"bufio"
	"flag"
	"fmt"
	"log"
	"os"
	"sort"
	"strconv"

crosbymichael

package main

import (
	"context"
	"syscall"
	"time"

	"github.com/Sirupsen/logrus"
	"github.com/containerd/containerd"
	"github.com/containerd/containerd/namespaces"

crosbymichael

package main

import (
	_ "context"

	_ "math"

	_ "net/http"

	_ "github.com/containerd/console"

crosbymichael

package main

import (
	"encoding/json"
	"log"
	"os"
	"os/exec"

	"github.com/docker/containerd/osutils"
)

crosbymichael

#define _GNU_SOURCE

#include <signal.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <errno.h>
#include <sys/types.h>
#include <sys/resource.h>

crosbymichael

Keybase proof

I hereby claim:

• I am crosbymichael on github.
• I am crosbymichael (https://keybase.io/crosbymichael) on keybase.
• I have a public key whose fingerprint is 03AC FE05 5FF8 E919 F278 00FA 0930 0471 AA36 D4B3

To claim this, I am signing this object:

crosbymichael

package dontfearthereaper

import "syscall"

// PR_SET_CHILD_SUBREAPER
const prSetSubreaper = 0x36

func init() {
	if _, _, err := syscall.RawSyscall(syscall.SYS_PRCTL, prSetSubreaper, 0, 0); err != 0 {
		panic(err)

crosbymichael

package main

import "github.com/opencontainers/specs"

func main() {
	device := specs.ThrottleDevice{}
	device.Major = 0
	device.Minor = 0
	var rate uint64
	rate = 292929