Merge pull request #3196 from weaveworks/issues/1770-proxy-dns-address

Make proxy use configured WeaveDNS address

prog/weaver/main.go

@@ -45,12 +45,20 @@ type ipamConfig struct {
 }
 
 type dnsConfig struct {
-	Domain                 string
-	ListenAddress          string
-	TTL                    int
-	ClientTimeout          time.Duration
-	EffectiveListenAddress string
-	ResolvConf             string
+	Domain        string
+	ListenAddress string
+	TTL           int
+	ClientTimeout time.Duration
+	ResolvConf    string
+}
+
+// return the address part of the DNS listen address, without ":53" on the end
+func (c dnsConfig) addressOnly() string {
+	addr, _, err := net.SplitHostPort(c.ListenAddress)
+	if err != nil {
+		Log.Fatalf("Error when parsing DNS listen address %q: %s", c.ListenAddress, err)
+	}
+	return addr
 }
 
 func (c *ipamConfig) Enabled() bool {
@@ -193,7 +201,6 @@ func main() {
 	mflag.StringVar(&dnsConfig.ListenAddress, []string{"-dns-listen-address"}, nameserver.DefaultListenAddress, "address to listen on for DNS requests")
 	mflag.IntVar(&dnsConfig.TTL, []string{"-dns-ttl"}, nameserver.DefaultTTL, "TTL for DNS request from our domain")
 	mflag.DurationVar(&dnsConfig.ClientTimeout, []string{"-dns-fallback-timeout"}, nameserver.DefaultClientTimeout, "timeout for fallback DNS requests")
-	mflag.StringVar(&dnsConfig.EffectiveListenAddress, []string{"-dns-effective-listen-address"}, "", "address DNS will actually be listening, after Docker port mapping")
 	mflag.StringVar(&dnsConfig.ResolvConf, []string{"-resolv-conf"}, "", "path to resolver configuration for fallback DNS lookups")
 	mflag.StringVar(&bridgeConfig.DatapathName, []string{"-datapath"}, "", "ODP datapath name")
 	mflag.BoolVar(&bridgeConfig.NoFastdp, []string{"-no-fastdp"}, false, "Disable Fast Datapath")
@@ -264,6 +271,8 @@ func main() {
 	var proxy *weaveproxy.Proxy
 	var err error
 	if proxyConfig.Enabled {
+		proxyConfig.DNSListenAddress = dnsConfig.addressOnly()
+		proxyConfig.DNSDomain = dnsConfig.Domain
 		if noDNS {
 			proxyConfig.WithoutDNS = true
 		}
@@ -636,17 +645,13 @@ func createDNSServer(config dnsConfig, router *mesh.Router, isKnownPeer func(mes
 	gossip, err := router.NewGossip("nameserver", ns)
 	checkFatal(err)
 	ns.SetGossip(gossip)
-	upstream := nameserver.NewUpstream(config.ResolvConf, config.EffectiveListenAddress)
+	upstream := nameserver.NewUpstream(config.ResolvConf, config.addressOnly())
 	dnsserver, err := nameserver.NewDNSServer(ns, config.Domain, config.ListenAddress,
 		upstream, uint32(config.TTL), config.ClientTimeout)
 	if err != nil {
 		Log.Fatal("Unable to start dns server: ", err)
 	}
-	listenAddr := config.ListenAddress
-	if config.EffectiveListenAddress != "" {
-		listenAddr = config.EffectiveListenAddress
-	}
-	Log.Println("Listening for DNS queries on", listenAddr)
+	Log.Println("Listening for DNS queries on", config.ListenAddress)
 	return ns, dnsserver
 }
 

proxy/create_container_interceptor.go

@@ -68,11 +68,11 @@ func (i *createContainerInterceptor) InterceptRequest(r *http.Request) error {
 		if err != nil {
 			return err
 		}
-		if dnsDomain := i.proxy.getDNSDomain(); dnsDomain != "" {
-			if err := i.setHostname(container, hostname, dnsDomain); err != nil {
+		if !i.proxy.WithoutDNS {
+			if err := i.setHostname(container, hostname, i.proxy.DNSDomain); err != nil {
 				return err
 			}
-			if err := i.proxy.setWeaveDNS(hostConfig, hostname, dnsDomain); err != nil {
+			if err := i.proxy.setWeaveDNS(hostConfig, hostname, i.proxy.DNSDomain); err != nil {
 				return err
 			}
 		}

proxy/proxy.go

@@ -61,6 +61,8 @@ type Config struct {
 	NoRewriteHosts      bool
 	TLSConfig           TLSConfig
 	WithoutDNS          bool
+	DNSListenAddress    string
+	DNSDomain           string
 	NoMulticastRoute    bool
 	KeepTXOn            bool
 	DockerBridge        string
@@ -78,7 +80,6 @@ type Proxy struct {
 	Config
 	client                 *weavedocker.Client
 	weave                  *weaveapi.Client
-	dockerBridgeIP         string
 	hostnameMatchRegexp    *regexp.Regexp
 	weaveWaitVolume        string
 	weaveWaitNoopVolume    string
@@ -158,15 +159,6 @@ func NewProxy(c Config) (*Proxy, error) {
 
 	Log.Info(p.client.Info())
 
-	if !p.WithoutDNS {
-		ip, err := weavenet.FindBridgeIP(c.DockerBridge, nil)
-		if err != nil {
-			return nil, err
-		}
-		p.dockerBridgeIP = ip.String()
-		Log.Infof("Using docker bridge IP for DNS: %v", p.dockerBridgeIP)
-	}
-
 	p.hostnameMatchRegexp, err = regexp.Compile(c.HostnameMatch)
 	if err != nil {
 		err := fmt.Errorf("Incorrect hostname match '%s': %s", c.HostnameMatch, err.Error())
@@ -595,7 +587,7 @@ func (proxy *Proxy) setWeaveDNS(hostConfig jsonObject, hostname, dnsDomain strin
 	if err != nil {
 		return err
 	}
-	hostConfig["Dns"] = append(dns, proxy.dockerBridgeIP)
+	hostConfig["Dns"] = append(dns, proxy.DNSListenAddress)
 
 	dnsSearch, err := hostConfig.StringArray("DnsSearch")
 	if err != nil {
@@ -612,14 +604,6 @@ func (proxy *Proxy) setWeaveDNS(hostConfig jsonObject, hostname, dnsDomain strin
 	return nil
 }
 
-func (proxy *Proxy) getDNSDomain() string {
-	if proxy.WithoutDNS {
-		return ""
-	}
-	domain, _ := proxy.weave.DNSDomain()
-	return domain
-}
-
 func (proxy *Proxy) updateContainerNetworkSettings(container jsonObject) error {
 	containerID, err := container.String("Id")
 	if err != nil {

proxy/start_container_interceptor.go

@@ -50,8 +50,8 @@ func (i *startContainerInterceptor) InterceptRequest(r *http.Request) error {
 						return err
 					}
 				}
-				if dnsDomain := i.proxy.getDNSDomain(); dnsDomain != "" {
-					if err := i.proxy.setWeaveDNS(hostConfig, container.Config.Hostname, dnsDomain); err != nil {
+				if !i.proxy.WithoutDNS {
+					if err := i.proxy.setWeaveDNS(hostConfig, container.Config.Hostname, i.proxy.DNSDomain); err != nil {
 						return err
 					}
 				}

weave

@@ -1234,7 +1234,6 @@ launch() {
         --host-root=/host \
         $(router_bridge_opts) \
         --ipalloc-range "$IPRANGE" \
-        --dns-effective-listen-address $DOCKER_BRIDGE_IP \
         --dns-listen-address $DOCKER_BRIDGE_IP:53 \
         --http-addr $HTTP_ADDR \
         --status-addr $STATUS_ADDR \