Merge pull request #1 from sourcelair/feature-better-link-dind

Add better linking between DinD and operator namespaces

Author: akalipetis

docker-compose.override.yml

@@ -0,0 +1,5 @@
+version: '3.7'
+
+services:
+  dind:
+    build: ./

docker-compose.yml

@@ -0,0 +1,20 @@
+version: '3.7'
+
+services:
+  dind:
+    image: sourcelair/swarm-dind-operator:${TAG:-local}
+    command:
+    - /usr/bin/swarm-operator-dind
+    - --image=${DIND_IMAGE:-docker:18.09-dind}
+    - --args=${DIND_ARGS}
+    - --stop-timeout=${DIND_STOP_TIMEOUT:-10}
+    - --binds=${DIND_BINDS}
+    volumes:
+      - /var/run/docker.sock:/var/run/docker.sock
+    init: true
+
+networks:
+  default:
+    name: ${NETWORK:-dind}
+    attachable: true
+    external: true

main.go

@@ -3,8 +3,10 @@ package main
 import (
 	"context"
 	"fmt"
+	"io/ioutil"
 	"os"
 	"os/signal"
+	"strings"
 	"syscall"
 
 	docker "github.com/fsouza/go-dockerclient"
@@ -31,12 +33,27 @@ func runOperator() int {
 	pflag.StringArrayVar(&containerBinds, "binds", []string{}, "the directories to bind in the container")
 	pflag.Parse()
 
+	filteredBinds := make([]string, 0, len(containerBinds))
+	for _, bind := range containerBinds {
+		if bind != "" {
+			filteredBinds = append(filteredBinds, bind)
+		}
+	}
+
 	args, err := shellquote.Split(containerArgs)
 	if err != nil {
 		fmt.Println(errors.Wrap(err, "invalid arguments given"))
 		return 42
 	}
 
+	data, err := ioutil.ReadFile("/proc/self/cpuset")
+	if err != nil {
+		fmt.Println(errors.Wrap(err, "cannot read cgroup file"))
+		return 42
+	}
+	parts := strings.Split(string(data), "/")
+	selfID := strings.TrimSpace(parts[len(parts)-1])
+
 	client, err := docker.NewClientFromEnv()
 	if err != nil {
 		fmt.Println(errors.Wrap(err, "cannot create client"))
@@ -78,18 +95,19 @@ func runOperator() int {
 	container, err := client.CreateContainer(docker.CreateContainerOptions{
 		Name: containerName,
 		Config: &docker.Config{
-			Cmd:      args,
-			Hostname: containerName,
-			Image:    imageName,
+			Cmd:   args,
+			Image: imageName,
 			Labels: map[string]string{
 				"com.sourcelair.swarm-dind-operator":      "true",
 				"com.sourcelair.swarm-dind-operator.name": containerName,
 			},
 			StopTimeout: containerStopTimeout,
 		},
 		HostConfig: &docker.HostConfig{
-			Privileged: true,
-			Binds:      containerBinds,
+			Privileged:  true,
+			Binds:       filteredBinds,
+			NetworkMode: fmt.Sprintf("container:%s", selfID),
+			PidMode:     fmt.Sprintf("container:%s", selfID),
 		},
 	})
 	if err != nil {