Add the ability to request a specific IP address when creating a new …

…endpoint.

Docker-DCO-1.1-Signed-off-by: Ross Boucher <rboucher@gmail.com> (github: boucher)

drivers/bridge/bridge.go

@@ -57,6 +57,7 @@ type networkConfiguration struct {
 
 // endpointConfiguration represents the user specified configuration for the sandbox endpoint
 type endpointConfiguration struct {
+	IPAddress    net.IP
 	MacAddress   net.HardwareAddr
 	PortBindings []types.PortBinding
 	ExposedPorts []types.TransportPort
@@ -724,7 +725,7 @@ func (d *driver) CreateEndpoint(nid, eid types.UUID, epInfo driverapi.EndpointIn
 	}
 
 	// v4 address for the sandbox side pipe interface
-	ip4, err := ipAllocator.RequestIP(n.bridge.bridgeIPv4, nil)
+	ip4, err := ipAllocator.RequestIP(n.bridge.bridgeIPv4, requestedIPAddress(epConfig))
 	if err != nil {
 		return err
 	}
@@ -1083,6 +1084,14 @@ func parseEndpointOptions(epOptions map[string]interface{}) (*endpointConfigurat
 		}
 	}
 
+	if opt, ok := epOptions[netlabel.IPAddress]; ok {
+		if ip, ok := opt.(net.IP); ok {
+			ec.IPAddress = ip
+		} else {
+			return nil, &ErrInvalidEndpointConfig{}
+		}
+	}
+
 	if opt, ok := epOptions[netlabel.PortMap]; ok {
 		if bs, ok := opt.([]types.PortBinding); ok {
 			ec.PortBindings = bs
@@ -1131,6 +1140,13 @@ func electMacAddress(epConfig *endpointConfiguration) net.HardwareAddr {
 	return netutils.GenerateRandomMAC()
 }
 
+func requestedIPAddress(epConfig *endpointConfiguration) net.IP {
+	if epConfig != nil && epConfig.IPAddress != nil {
+		return epConfig.IPAddress
+	}
+	return nil
+}
+
 // Generates a name to be used for a virtual ethernet
 // interface. The name is constructed by 'veth' appended
 // by a randomly generated hex value. (example: veth0f60e2c)

drivers/bridge/bridge_test.go

@@ -244,6 +244,9 @@ func TestCreateLinkWithOptions(t *testing.T) {
 	epOptions := make(map[string]interface{})
 	epOptions[netlabel.MacAddress] = mac
 
+	ip := net.ParseIP("172.17.42.111")
+	epOptions[netlabel.IPAddress] = ip
+
 	te := &testEndpoint{ifaces: []*testInterface{}}
 	err = d.CreateEndpoint("net1", "ep", te, epOptions)
 	if err != nil {
@@ -262,7 +265,12 @@ func TestCreateLinkWithOptions(t *testing.T) {
 	}
 
 	if !bytes.Equal(mac, veth.Attrs().HardwareAddr) {
-		t.Fatalf("Failed to parse and program endpoint configuration")
+		t.Fatalf("Failed to parse and program endpoint MAC configuration")
+	}
+
+	teIP4 := te.ifaces[0].addr.IP.To4()
+	if !ip.Equal(teIP4) {
+		t.Fatalf("Failed to parse and program endpoint IP configuration")
 	}
 }
 

netlabel/labels.go

@@ -10,6 +10,9 @@ const (
 	// MacAddress constant represents Mac Address config of a Container
 	MacAddress = "io.docker.network.endpoint.macaddress"
 
+	// IPAddress constant represents requesting a specific IP address for a Container
+	IPAddress = "io.docker.network.endpoint.ipaddress"
+
 	// ExposedPorts constant represents exposedports of a Container
 	ExposedPorts = "io.docker.network.endpoint.exposedports"