diff --git a/builder/openstack/builder.go b/builder/openstack/builder.go
index 3007d0461..f802e2523 100644
--- a/builder/openstack/builder.go
+++ b/builder/openstack/builder.go
@@ -126,9 +126,10 @@ func (b *Builder) Run(ctx context.Context, ui packer.Ui, hook packer.Hook) (pack
 			Wait: b.config.RackconnectWait,
 		},
 		&StepAllocateIp{
-			FloatingIPNetwork: b.config.FloatingIPNetwork,
-			FloatingIP:        b.config.FloatingIP,
-			ReuseIPs:          b.config.ReuseIPs,
+			FloatingIPNetwork:     b.config.FloatingIPNetwork,
+			FloatingIP:            b.config.FloatingIP,
+			ReuseIPs:              b.config.ReuseIPs,
+			InstanceFloatingIPNet: b.config.InstanceFloatingIPNet,
 		},
 		&communicator.StepConnect{
 			Config: &b.config.RunConfig.Comm,
diff --git a/builder/openstack/networks.go b/builder/openstack/networks.go
index 30c435ee8..537d9ce5a 100644
--- a/builder/openstack/networks.go
+++ b/builder/openstack/networks.go
@@ -2,6 +2,7 @@ package openstack
 
 import (
 	"fmt"
+	"log"
 
 	"github.com/google/uuid"
 	"github.com/gophercloud/gophercloud"
@@ -66,7 +67,10 @@ func FindFreeFloatingIP(client *gophercloud.ServiceClient) (*floatingips.Floatin
 // GetInstancePortID returns internal port of the instance that can be used for
 // the association of a floating IP.
 // It will return an ID of a first port if there are many.
-func GetInstancePortID(client *gophercloud.ServiceClient, id string) (string, error) {
+func GetInstancePortID(client *gophercloud.ServiceClient, id string, instance_float_net string) (string, error) {
+
+	selected_interface := 0
+
 	interfacesPage, err := attachinterfaces.List(client, id).AllPages()
 	if err != nil {
 		return "", err
@@ -79,7 +83,16 @@ func GetInstancePortID(client *gophercloud.ServiceClient, id string) (string, er
 		return "", fmt.Errorf("instance '%s' has no interfaces", id)
 	}
 
-	return interfaces[0].PortID, nil
+	for i := 0; i < len(interfaces); i++ {
+		log.Printf("Instance interface: %v: %+v\n", i, interfaces[i])
+		if interfaces[i].NetID == instance_float_net {
+			log.Printf("Found preferred interface: %v\n", i)
+			selected_interface = i
+			log.Printf("Using interface value: %v", selected_interface)
+		}
+	}
+
+	return interfaces[selected_interface].PortID, nil
 }
 
 // CheckFloatingIPNetwork checks provided network reference and returns a valid
diff --git a/builder/openstack/run_config.go b/builder/openstack/run_config.go
index c0bac7e6f..0400d2384 100644
--- a/builder/openstack/run_config.go
+++ b/builder/openstack/run_config.go
@@ -17,23 +17,24 @@ type RunConfig struct {
 	SSHInterface string              `mapstructure:"ssh_interface"`
 	SSHIPVersion string              `mapstructure:"ssh_ip_version"`
 
-	SourceImage        string            `mapstructure:"source_image"`
-	SourceImageName    string            `mapstructure:"source_image_name"`
-	SourceImageFilters ImageFilter       `mapstructure:"source_image_filter"`
-	Flavor             string            `mapstructure:"flavor"`
-	AvailabilityZone   string            `mapstructure:"availability_zone"`
-	RackconnectWait    bool              `mapstructure:"rackconnect_wait"`
-	FloatingIPNetwork  string            `mapstructure:"floating_ip_network"`
-	FloatingIP         string            `mapstructure:"floating_ip"`
-	ReuseIPs           bool              `mapstructure:"reuse_ips"`
-	SecurityGroups     []string          `mapstructure:"security_groups"`
-	Networks           []string          `mapstructure:"networks"`
-	Ports              []string          `mapstructure:"ports"`
-	UserData           string            `mapstructure:"user_data"`
-	UserDataFile       string            `mapstructure:"user_data_file"`
-	InstanceName       string            `mapstructure:"instance_name"`
-	InstanceMetadata   map[string]string `mapstructure:"instance_metadata"`
-	ForceDelete        bool              `mapstructure:"force_delete"`
+	SourceImage           string            `mapstructure:"source_image"`
+	SourceImageName       string            `mapstructure:"source_image_name"`
+	SourceImageFilters    ImageFilter       `mapstructure:"source_image_filter"`
+	Flavor                string            `mapstructure:"flavor"`
+	AvailabilityZone      string            `mapstructure:"availability_zone"`
+	RackconnectWait       bool              `mapstructure:"rackconnect_wait"`
+	FloatingIPNetwork     string            `mapstructure:"floating_ip_network"`
+	FloatingIP            string            `mapstructure:"floating_ip"`
+	ReuseIPs              bool              `mapstructure:"reuse_ips"`
+	SecurityGroups        []string          `mapstructure:"security_groups"`
+	Networks              []string          `mapstructure:"networks"`
+	InstanceFloatingIPNet string            `mapstructure:"instance_floating_ip_net"`
+	Ports                 []string          `mapstructure:"ports"`
+	UserData              string            `mapstructure:"user_data"`
+	UserDataFile          string            `mapstructure:"user_data_file"`
+	InstanceName          string            `mapstructure:"instance_name"`
+	InstanceMetadata      map[string]string `mapstructure:"instance_metadata"`
+	ForceDelete           bool              `mapstructure:"force_delete"`
 
 	ConfigDrive bool `mapstructure:"config_drive"`
 
diff --git a/builder/openstack/step_allocate_ip.go b/builder/openstack/step_allocate_ip.go
index a63faa836..8b0701491 100644
--- a/builder/openstack/step_allocate_ip.go
+++ b/builder/openstack/step_allocate_ip.go
@@ -11,9 +11,10 @@ import (
 )
 
 type StepAllocateIp struct {
-	FloatingIPNetwork string
-	FloatingIP        string
-	ReuseIPs          bool
+	FloatingIPNetwork     string
+	FloatingIP            string
+	ReuseIPs              bool
+	InstanceFloatingIPNet string
 }
 
 func (s *StepAllocateIp) Run(ctx context.Context, state multistep.StateBag) multistep.StepAction {
@@ -114,7 +115,7 @@ func (s *StepAllocateIp) Run(ctx context.Context, state multistep.StateBag) mult
 		ui.Say(fmt.Sprintf("Associating floating IP '%s' (%s) with instance port...",
 			instanceIP.ID, instanceIP.FloatingIP))
 
-		portID, err := GetInstancePortID(computeClient, server.ID)
+		portID, err := GetInstancePortID(computeClient, server.ID, s.InstanceFloatingIPNet)
 		if err != nil {
 			err := fmt.Errorf("Error getting interfaces of the instance '%s': %s", server.ID, err)
 			state.Put("error", err)
diff --git a/website/source/docs/builders/openstack.html.md b/website/source/docs/builders/openstack.html.md
index 45d87a7b0..97d9cc9e4 100644
--- a/website/source/docs/builders/openstack.html.md
+++ b/website/source/docs/builders/openstack.html.md
@@ -155,6 +155,13 @@ builder.
 -   `insecure` (boolean) - Whether or not the connection to OpenStack can be
     done over an insecure connection. By default this is false.
 
+-   `instance_floating_ip_net` (string) - The ID of the network to which the
+    instance is attached and which should be used to associate with the floating
+    IP. This provides control over the floating ip association on multi-homed
+    instances. The association otherwise depends on a first-returned-interface
+    policy which could fail if the network to which it is connected is
+    unreachable from the floating IP network.
+
 -   `key` (string) - Client private key file path for SSL client
     authentication. If omitted the `OS_KEY` environment variable can be used.