Support attaching a public IP on master boot

pkg/bootstrap/bootstrapper.go

@@ -19,13 +19,14 @@ package bootstrap
 import (
 	"encoding/json"
 	"fmt"
-	"github.com/golang/glog"
 	"io/ioutil"
+	"os"
+	"strings"
+
+	"github.com/golang/glog"
 	"k8s.io/kubernetes/pkg/cloudprovider"
 	"k8s.io/kubernetes/pkg/util/exec"
 	"k8s.io/kubernetes/pkg/util/mount"
-	"os"
-	"strings"
 )
 
 // Bootstrapper is the main bootstrapping manager class
@@ -54,11 +55,17 @@ func (b *Bootstrapper) RunOnce() error {
 		return fmt.Errorf("unable to build cloud provider: %v", err)
 	}
 
+	// The master volume acts as a mutex, so we always mount it first
 	err = b.mountMasterVolume()
 	if err != nil {
 		return fmt.Errorf("unable to mount master volume: %v", err)
 	}
 
+	err = b.configureMasterPublicIP()
+	if err != nil {
+		return fmt.Errorf("unable to associate master IP: %v", err)
+	}
+
 	err = b.configureMasterRoute()
 	if err != nil {
 		return fmt.Errorf("unable to configure master route: %v", err)
@@ -102,6 +109,18 @@ func (b *Bootstrapper) buildCloudProvider() error {
 	return nil
 }
 
+func (b *Bootstrapper) configureMasterPublicIP() error {
+	ip := b.config.MasterPublicIP
+
+	err := b.masterBootstrap.AttachPublicIP(ip)
+	if err != nil {
+		// TODO: This is retryable
+		return fmt.Errorf("error attaching public IP (%s): %v", ip, err)
+	}
+
+	return nil
+}
+
 func (b *Bootstrapper) mountMasterVolume() error {
 	// We could discover the volume using metadata (at least on AWS),
 	// but it is probably easier just to rely on it being present in config

pkg/bootstrap/config.go

@@ -25,7 +25,8 @@ type Configuration struct {
 	CloudProvider       string
 	CloudProviderConfig string
 
-	MasterCIDR string
+	MasterPublicIP string
+	MasterCIDR     string
 
 	ClusterID string
 

pkg/cloudprovider/cloud.go

@@ -166,4 +166,7 @@ type MasterBootstrap interface {
 	// The volume id will typically be an ID for the default volume type for that cloud,
 	// but is an opaque token typically provided to the bootstrapper in a config file.
 	AttachMasterVolume(volumeID string) (string, error)
+
+	// Attaches the specified public IP to the master
+	AttachPublicIP(ip string) error
 }

pkg/cloudprovider/providers/aws/aws.go

@@ -101,6 +101,9 @@ type EC2 interface {
 	DeleteRoute(request *ec2.DeleteRouteInput) (*ec2.DeleteRouteOutput, error)
 
 	ModifyInstanceAttribute(request *ec2.ModifyInstanceAttributeInput) (*ec2.ModifyInstanceAttributeOutput, error)
+
+	DescribeAddresses(*ec2.DescribeAddressesInput) ([]*ec2.Address, error)
+	AssociateAddress(*ec2.AssociateAddressInput) (*ec2.AssociateAddressOutput, error)
 }
 
 // This is a simple pass-through of the ELB client interface, which allows for testing
@@ -443,6 +446,19 @@ func (s *awsSdkEC2) ModifyInstanceAttribute(request *ec2.ModifyInstanceAttribute
 	return s.ec2.ModifyInstanceAttribute(request)
 }
 
+func (s *awsSdkEC2) DescribeAddresses(request *ec2.DescribeAddressesInput) ([]*ec2.Address, error) {
+	// Not paged
+	response, err := s.ec2.DescribeAddresses(request)
+	if err != nil {
+		return nil, fmt.Errorf("error listing AWS addresses: %v", err)
+	}
+	return response.Addresses, nil
+}
+
+func (s *awsSdkEC2) AssociateAddress(request *ec2.AssociateAddressInput) (*ec2.AssociateAddressOutput, error) {
+	return s.ec2.AssociateAddress(request)
+}
+
 func init() {
 	cloudprovider.RegisterCloudProvider(ProviderName, func(config io.Reader) (cloudprovider.Interface, error) {
 		creds := credentials.NewChainCredentials(
@@ -1209,6 +1225,41 @@ func (c *AWSCloud) AttachMasterVolume(volumeID string) (string, error) {
 	return c.attachVolumeAt(awsInstance, disk, mountDevice, alreadyAttached)
 }
 
+// Implements MasterBootstrap.AttachPublicIP
+func (c *AWSCloud) AttachPublicIP(ip string) error {
+	instanceName := "" // self
+	awsInstance, err := c.getAwsInstance(instanceName)
+	if err != nil {
+		return err
+	}
+
+	addresses, err := c.ec2.DescribeAddresses(&ec2.DescribeAddressesInput{
+		PublicIps: []*string{aws.String(ip)},
+	})
+	if err != nil {
+		return err
+	}
+
+	if len(addresses) != 1 {
+		return fmt.Errorf("unexpectedly found multiple public addresses matching IP: %q", ip)
+	}
+
+	request := &ec2.AssociateAddressInput{
+		AllocationId:       addresses[0].AllocationId,
+		AllowReassociation: aws.Bool(false), // Seems safer
+		InstanceId:         &awsInstance.awsID,
+	}
+
+	response, err := c.ec2.AssociateAddress(request)
+	if err != nil {
+		return fmt.Errorf("error associating public IP %q with instance %q: %v", ip, awsInstance.awsID, err)
+	}
+
+	glog.V(2).Info("associated public IP %q with instance %q, reservation id=%q", ip, awsInstance.awsID, aws.StringValue(response.AssociationId))
+
+	return nil
+}
+
 // Implements Volumes.DetachDisk
 func (aws *AWSCloud) DetachDisk(instanceName string, diskName string) (string, error) {
 	disk, err := newAWSDisk(aws, diskName)