Detect Nodes Network MTU

This commit adds the support to detect the Nodes
Network MTU so that the Namespace Networks use the
same MTU as the host.

bindata/network/kuryr/003-config.yaml

@@ -60,7 +60,7 @@ data:
     pod_security_groups = {{ default "default" .PodSecurityGroups }}
     resource_tags = {{ default "" .ResourceTags }}
     external_svc_net = {{ .ExternalNetwork }}
-    #network_device_mtu = 1500
+    network_device_mtu = {{ .NodesNetworkMTU }}
 
     [neutron]
     auth_type = {{ default "password" .OpenStackCloud.AuthType }}

pkg/bootstrap/types.go

@@ -9,6 +9,7 @@ type KuryrBootstrapResult struct {
 	PodSubnetpool            string
 	WorkerNodesRouter        string
 	WorkerNodesSubnet        string
+	NodesNetworkMTU          int
 	PodSecurityGroups        []string
 	ExternalNetwork          string
 	ClusterID                string

pkg/network/kuryr.go

@@ -112,6 +112,9 @@ func renderKuryr(conf *operv1.NetworkSpec, bootstrapResult *bootstrap.BootstrapR
 	data.Data["WebhookCert"] = b.WebhookCert
 	data.Data["WebhookKey"] = b.WebhookKey
 
+	// Nodes Network MTU
+	data.Data["NodesNetworkMTU"] = b.NodesNetworkMTU
+
 	manifests, err := render.RenderDir(filepath.Join(manifestDir, "network/kuryr"), &data)
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to render manifests")

pkg/platform/openstack/kuryr_bootstrap.go

@@ -330,6 +330,11 @@ func BootstrapKuryr(conf *operv1.NetworkSpec, kubeClient client.Client) (*bootst
 	if err != nil {
 		return nil, errors.Wrap(err, "failed to find worker nodes subnet")
 	}
+	mtu, err := getOpenStackNetworkMTU(client, workerSubnet.NetworkID)
+	if err != nil {
+		return nil, errors.Wrap(err, "failed to get network MTU")
+	}
+	log.Printf("Found Nodes Network MTU %d", mtu)
 
 	log.Printf("Found worker nodes subnet %s", workerSubnet.ID)
 	router, err := ensureOpenStackRouter(client, generateName("external-router", clusterID), tag, workerSubnet.NetworkID)
@@ -642,6 +647,7 @@ func BootstrapKuryr(conf *operv1.NetworkSpec, kubeClient client.Client) (*bootst
 			PodSubnetpool:            podSubnetpoolId,
 			WorkerNodesRouter:        routerId,
 			WorkerNodesSubnet:        workerSubnet.ID,
+			NodesNetworkMTU:          mtu,
 			PodSecurityGroups:        []string{podSgId},
 			ExternalNetwork:          externalNetwork,
 			ClusterID:                clusterID,

pkg/platform/openstack/networking.go

@@ -6,6 +6,7 @@ import (
 	"github.com/gophercloud/gophercloud"
 	"github.com/gophercloud/gophercloud/openstack/networking/v2/extensions/attributestags"
 	"github.com/gophercloud/gophercloud/openstack/networking/v2/extensions/layer3/routers"
+	"github.com/gophercloud/gophercloud/openstack/networking/v2/extensions/mtu"
 	"github.com/gophercloud/gophercloud/openstack/networking/v2/extensions/security/groups"
 	"github.com/gophercloud/gophercloud/openstack/networking/v2/extensions/security/rules"
 	"github.com/gophercloud/gophercloud/openstack/networking/v2/extensions/subnetpools"
@@ -114,6 +115,21 @@ func findOpenStackNetwork(client *gophercloud.ServiceClient, tag string) (networ
 	}
 }
 
+// Gets the MTU of a Network
+func getOpenStackNetworkMTU(client *gophercloud.ServiceClient, networkID string) (int, error) {
+	networkMTU := 0
+	type NetworkMTU struct {
+		networks.Network
+		mtu.NetworkMTUExt
+	}
+	var mtu NetworkMTU
+	err := networks.Get(client, networkID).ExtractInto(&mtu)
+	if err != nil {
+		return networkMTU, errors.Wrap(err, "failed to extract network MTU")
+	}
+	return mtu.MTU, nil
+}
+
 // Looks for a Neutron subnet by name and tag. In case of not found, looks for a
 // provided custom subnet by tag. Fails if any not found.
 func findOpenStackSubnet(client *gophercloud.ServiceClient, name, tag, clusterID string) (subnets.Subnet, error) {