openstack: Autodetect LBaaS v1 vs v2

This removes the need to manually specify the version in all but unusual
cases.

For most installs this will effectively flip the default from
v1 (deprecated) to v2 so conservative existing installs may want to
manually configure "lb-version = v1" before upgrading.

pkg/cloudprovider/providers/openstack/openstack.go

@@ -83,7 +83,7 @@ type LoadBalancer struct {
 }
 
 type LoadBalancerOpts struct {
-	LBVersion         string     `gcfg:"lb-version"` // v1 or v2
+	LBVersion         string     `gcfg:"lb-version"` // overrides autodetection. v1 or v2
 	SubnetId          string     `gcfg:"subnet-id"`  // required
 	FloatingNetworkId string     `gcfg:"floating-network-id"`
 	LBMethod          string     `gcfg:"lb-method"`
@@ -526,13 +526,35 @@ func (os *OpenStack) LoadBalancer() (cloudprovider.LoadBalancer, bool) {
 		return nil, false
 	}
 
+	lbversion := os.lbOpts.LBVersion
+	if lbversion == "" {
+		// No version specified, try newest supported by server
+		netExts, err := networkExtensions(network)
+		if err != nil {
+			glog.Warningf("Failed to list neutron extensions: %v", err)
+			return nil, false
+		}
+
+		if netExts["lbaasv2"] {
+			lbversion = "v2"
+		} else if netExts["lbaas"] {
+			lbversion = "v1"
+		} else {
+			glog.Warningf("Failed to find neutron LBaaS extension (v1 or v2)")
+			return nil, false
+		}
+		glog.V(3).Infof("Using LBaaS extension %v", lbversion)
+	}
+
 	glog.V(1).Info("Claiming to support LoadBalancer")
 
 	if os.lbOpts.LBVersion == "v2" {
 		return &LbaasV2{LoadBalancer{network, compute, os.lbOpts}}, true
-	} else {
-
+	} else if lbversion == "v1" {
 		return &LbaasV1{LoadBalancer{network, compute, os.lbOpts}}, true
+	} else {
+		glog.Warningf("Config error: unrecognised lb-version \"%v\"", lbversion)
+		return nil, false
 	}
 }
 

pkg/cloudprovider/providers/openstack/openstack_loadbalancer.go

@@ -20,6 +20,7 @@ import (
 	"time"
 
 	"github.com/rackspace/gophercloud"
+	"github.com/rackspace/gophercloud/openstack/networking/v2/extensions"
 	"github.com/rackspace/gophercloud/openstack/networking/v2/extensions/layer3/floatingips"
 	"github.com/rackspace/gophercloud/openstack/networking/v2/extensions/lbaas/members"
 	"github.com/rackspace/gophercloud/openstack/networking/v2/extensions/lbaas/monitors"
@@ -55,6 +56,24 @@ type LbaasV2 struct {
 	LoadBalancer
 }
 
+func networkExtensions(client *gophercloud.ServiceClient) (map[string]bool, error) {
+	seen := make(map[string]bool)
+
+	pager := extensions.List(client)
+	err := pager.EachPage(func(page pagination.Page) (bool, error) {
+		exts, err := extensions.ExtractExtensions(page)
+		if err != nil {
+			return false, err
+		}
+		for _, ext := range exts {
+			seen[ext.Alias] = true
+		}
+		return true, nil
+	})
+
+	return seen, err
+}
+
 func getPortIDByIP(client *gophercloud.ServiceClient, ipAddress string) (string, error) {
 	var portID string
 

pkg/cloudprovider/providers/openstack/openstack_test.go

@@ -205,7 +205,11 @@ func TestLoadBalancer(t *testing.T) {
 		t.Skipf("No config found in environment")
 	}
 
-	cfg.LoadBalancer.LBVersion = "v1"
+	versions := []string{"v1", "v2", ""}
+
+	for _, v := range versions {
+		t.Logf("Trying LBVersion = '%s'\n", v)
+		cfg.LoadBalancer.LBVersion = v
 
 		os, err := newOpenStack(cfg)
 		if err != nil {
@@ -225,31 +229,6 @@ func TestLoadBalancer(t *testing.T) {
 			t.Fatalf("GetLoadBalancer(\"noexist\") returned exists")
 		}
 	}
-
-func TestLoadBalancerV2(t *testing.T) {
-	cfg, ok := configFromEnv()
-	if !ok {
-		t.Skipf("No config found in environment")
-	}
-	cfg.LoadBalancer.LBVersion = "v2"
-
-	os, err := newOpenStack(cfg)
-	if err != nil {
-		t.Fatalf("Failed to construct/authenticate OpenStack: %s", err)
-	}
-
-	lbaas, ok := os.LoadBalancer()
-	if !ok {
-		t.Fatalf("LoadBalancer() returned false - perhaps your stack doesn't support Neutron?")
-	}
-
-	_, exists, err := lbaas.GetLoadBalancer(testClusterName, &api.Service{ObjectMeta: api.ObjectMeta{Name: "noexist"}})
-	if err != nil {
-		t.Fatalf("GetLoadBalancer(\"noexist\") returned error: %s", err)
-	}
-	if exists {
-		t.Fatalf("GetLoadBalancer(\"noexist\") returned exists")
-	}
 }
 
 func TestZones(t *testing.T) {