Merge branch 'dns_server_side'

+ Configure dns configuration host-wide with 'docker -d -dns'
+ Detect faulty DNS configuration and replace it with a public default

api.go

@@ -434,17 +434,23 @@ func postImagesPush(srv *Server, version float64, w http.ResponseWriter, r *http
 
 func postContainersCreate(srv *Server, version float64, w http.ResponseWriter, r *http.Request, vars map[string]string) error {
 	config := &Config{}
+	out := &APIRun{}
+
 	if err := json.NewDecoder(r.Body).Decode(config); err != nil {
 		return err
 	}
+
+	if len(config.Dns) == 0 && len(srv.runtime.Dns) == 0 && utils.CheckLocalDns() {
+		out.Warnings = append(out.Warnings, fmt.Sprintf("WARNING: Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns))
+		config.Dns = defaultDns
+	}
+
 	id, err := srv.ContainerCreate(config)
 	if err != nil {
 		return err
 	}
+	out.ID = id
 
-	out := &APIRun{
-		ID: id,
-	}
 	if config.Memory > 0 && !srv.runtime.capabilities.MemoryLimit {
 		log.Println("WARNING: Your kernel does not support memory limit capabilities. Limitation discarded.")
 		out.Warnings = append(out.Warnings, "Your kernel does not support memory limit capabilities. Limitation discarded.")
@@ -453,6 +459,7 @@ func postContainersCreate(srv *Server, version float64, w http.ResponseWriter, r
 		log.Println("WARNING: Your kernel does not support swap limit capabilities. Limitation discarded.")
 		out.Warnings = append(out.Warnings, "Your kernel does not support memory swap capabilities. Limitation discarded.")
 	}
+
 	b, err := json.Marshal(out)
 	if err != nil {
 		return err

builder.go

@@ -2,11 +2,14 @@ package docker
 
 import (
 	"fmt"
+	"github.com/dotcloud/docker/utils"
 	"os"
 	"path"
 	"time"
 )
 
+var defaultDns = []string{"8.8.8.8", "8.8.4.4"}
+
 type Builder struct {
 	runtime      *Runtime
 	repositories *TagStore
@@ -66,15 +69,26 @@ func (builder *Builder) Create(config *Config) (*Container, error) {
 		return nil, err
 	}
 
+	if len(config.Dns) == 0 && len(builder.runtime.Dns) == 0 && utils.CheckLocalDns() {
+		//"WARNING: Docker detected local DNS server on resolv.conf. Using default external servers: %v", defaultDns
+		builder.runtime.Dns = defaultDns
+	}
+
 	// If custom dns exists, then create a resolv.conf for the container
-	if len(config.Dns) > 0 {
+	if len(config.Dns) > 0 || len(builder.runtime.Dns) > 0 {
+		var dns []string
+		if len(config.Dns) > 0 {
+			dns = config.Dns
+		} else {
+			dns = builder.runtime.Dns
+		}
 		container.ResolvConfPath = path.Join(container.root, "resolv.conf")
 		f, err := os.Create(container.ResolvConfPath)
 		if err != nil {
 			return nil, err
 		}
 		defer f.Close()
-		for _, dns := range config.Dns {
+		for _, dns := range dns {
 			if _, err := f.Write([]byte("nameserver " + dns + "\n")); err != nil {
 				return nil, err
 			}

docker/docker.go

@@ -34,6 +34,7 @@ func main() {
 	pidfile := flag.String("p", "/var/run/docker.pid", "File containing process PID")
 	flHost := flag.String("H", fmt.Sprintf("%s:%d", host, port), "Host:port to bind/connect to")
 	flEnableCors := flag.Bool("api-enable-cors", false, "Enable CORS requests in the remote api.")
+	flDns := flag.String("dns", "", "Set custom dns servers")
 	flag.Parse()
 	if *bridgeName != "" {
 		docker.NetworkBridgeIface = *bridgeName
@@ -66,7 +67,7 @@ func main() {
 			flag.Usage()
 			return
 		}
-		if err := daemon(*pidfile, host, port, *flAutoRestart, *flEnableCors); err != nil {
+		if err := daemon(*pidfile, host, port, *flAutoRestart, *flEnableCors, *flDns); err != nil {
 			log.Fatal(err)
 			os.Exit(-1)
 		}
@@ -105,7 +106,7 @@ func removePidFile(pidfile string) {
 	}
 }
 
-func daemon(pidfile, addr string, port int, autoRestart, enableCors bool) error {
+func daemon(pidfile, addr string, port int, autoRestart, enableCors bool, flDns string) error {
 	if addr != "127.0.0.1" {
 		log.Println("/!\\ DON'T BIND ON ANOTHER IP ADDRESS THAN 127.0.0.1 IF YOU DON'T KNOW WHAT YOU'RE DOING /!\\")
 	}
@@ -122,8 +123,11 @@ func daemon(pidfile, addr string, port int, autoRestart, enableCors bool) error
 		removePidFile(pidfile)
 		os.Exit(0)
 	}()
-
-	server, err := docker.NewServer(autoRestart, enableCors)
+	var dns []string
+	if flDns != "" {
+		dns = []string{flDns}
+	}
+	server, err := docker.NewServer(autoRestart, enableCors, dns)
 	if err != nil {
 		return err
 	}

runtime.go

@@ -32,6 +32,7 @@ type Runtime struct {
 	autoRestart    bool
 	volumes        *Graph
 	srv            *Server
+	Dns            []string
 }
 
 var sysInitPath string
@@ -245,11 +246,12 @@ func (runtime *Runtime) UpdateCapabilities(quiet bool) {
 }
 
 // FIXME: harmonize with NewGraph()
-func NewRuntime(autoRestart bool) (*Runtime, error) {
+func NewRuntime(autoRestart bool, dns []string) (*Runtime, error) {
 	runtime, err := NewRuntimeFromDirectory("/var/lib/docker", autoRestart)
 	if err != nil {
 		return nil, err
 	}
+	runtime.Dns = dns
 
 	if k, err := utils.GetKernelVersion(); err != nil {
 		log.Printf("WARNING: %s\n", err)

server.go

@@ -978,11 +978,11 @@ func (srv *Server) ImageInspect(name string) (*Image, error) {
 	return nil, fmt.Errorf("No such image: %s", name)
 }
 
-func NewServer(autoRestart, enableCors bool) (*Server, error) {
+func NewServer(autoRestart, enableCors bool, dns ListOpts) (*Server, error) {
 	if runtime.GOARCH != "amd64" {
 		log.Fatalf("The docker runtime currently only supports amd64 (not %s). This will change in the future. Aborting.", runtime.GOARCH)
 	}
-	runtime, err := NewRuntime(autoRestart)
+	runtime, err := NewRuntime(autoRestart, dns)
 	if err != nil {
 		return nil, err
 	}

utils/utils.go

@@ -70,7 +70,7 @@ type progressReader struct {
 	readProgress int           // How much has been read so far (bytes)
 	lastUpdate   int           // How many bytes read at least update
 	template     string        // Template to print. Default "%v/%v (%v)"
-	sf *StreamFormatter
+	sf           *StreamFormatter
 }
 
 func (r *progressReader) Read(p []byte) (n int, err error) {
@@ -103,7 +103,7 @@ func (r *progressReader) Close() error {
 	return io.ReadCloser(r.reader).Close()
 }
 func ProgressReader(r io.ReadCloser, size int, output io.Writer, template []byte, sf *StreamFormatter) *progressReader {
-      	tpl := string(template)
+	tpl := string(template)
 	if tpl == "" {
 		tpl = string(sf.FormatProgress("", "%v/%v (%v)"))
 	}
@@ -599,7 +599,7 @@ func (sf *StreamFormatter) FormatStatus(format string, a ...interface{}) []byte
 	sf.used = true
 	str := fmt.Sprintf(format, a...)
 	if sf.json {
-		b, err := json.Marshal(&JSONMessage{Status:str});
+		b, err := json.Marshal(&JSONMessage{Status: str})
 		if err != nil {
 			return sf.FormatError(err)
 		}
@@ -611,7 +611,7 @@ func (sf *StreamFormatter) FormatStatus(format string, a ...interface{}) []byte
 func (sf *StreamFormatter) FormatError(err error) []byte {
 	sf.used = true
 	if sf.json {
-		if b, err := json.Marshal(&JSONMessage{Error:err.Error()}); err == nil {
+		if b, err := json.Marshal(&JSONMessage{Error: err.Error()}); err == nil {
 			return b
 		}
 		return []byte("{\"error\":\"format error\"}")
@@ -622,10 +622,10 @@ func (sf *StreamFormatter) FormatError(err error) []byte {
 func (sf *StreamFormatter) FormatProgress(action, str string) []byte {
 	sf.used = true
 	if sf.json {
-		b, err := json.Marshal(&JSONMessage{Status: action, Progress:str})
+		b, err := json.Marshal(&JSONMessage{Status: action, Progress: str})
 		if err != nil {
-                        return nil
-                }
+			return nil
+		}
 		return b
 	}
 	return []byte(action + " " + str + "\r")
@@ -634,3 +634,20 @@ func (sf *StreamFormatter) FormatProgress(action, str string) []byte {
 func (sf *StreamFormatter) Used() bool {
 	return sf.used
 }
+
+func CheckLocalDns() bool {
+	resolv, err := ioutil.ReadFile("/etc/resolv.conf")
+	if err != nil {
+		Debugf("Error openning resolv.conf: %s", err)
+		return false
+	}
+	for _, ip := range []string{
+		"127.0.0.1",
+		"127.0.1.1",
+	} {
+		if strings.Contains(string(resolv), ip) {
+			return true
+		}
+	}
+	return false
+}