Add config option for MTU setting

Author: wnagele

cmd/main.go

@@ -68,6 +68,7 @@ func main() {
 	var probeAddr string
 	var secureMetrics bool
 	var enableHTTP2 bool
+	var mtu int
 	var tlsOpts []func(*tls.Config)
 	flag.StringVar(&metricsAddr, "metrics-bind-address", "0", "The address the metrics endpoint binds to. "+
 		"Use :8443 for HTTPS or :8080 for HTTP, or leave as 0 to disable the metrics service.")
@@ -86,6 +87,8 @@ func main() {
 	flag.StringVar(&metricsCertKey, "metrics-cert-key", "tls.key", "The name of the metrics server key file.")
 	flag.BoolVar(&enableHTTP2, "enable-http2", false,
 		"If set, HTTP/2 will be enabled for the metrics and webhook servers")
+	flag.IntVar(&mtu, "mtu", 1372,
+		"The MTU to configure for CNI network interfaces.")
 	opts := zap.Options{
 		Development: true,
 	}
@@ -219,6 +222,7 @@ func main() {
 		Client:     mgr.GetClient(),
 		Scheme:     mgr.GetScheme(),
 		Identifier: identifier.New(),
+		MTU:        mtu,
 	}).SetupWithManager(mgr); err != nil {
 		setupLog.Error(err, "unable to create controller", "controller", "VPCAttachment")
 		os.Exit(1)

internal/cniconfig/cniconfig.go

@@ -25,7 +25,7 @@ type PluginConfGalactic struct {
 	IPAM          cni.IPAM          `json:"ipam,omitempty"`
 }
 
-func CNIConfigForVPCAttachment(vpc galacticv1alpha.VPC, vpcAttachment galacticv1alpha.VPCAttachment) (NetConfList, error) {
+func CNIConfigForVPCAttachment(vpc galacticv1alpha.VPC, vpcAttachment galacticv1alpha.VPCAttachment, mtu int) (NetConfList, error) {
 	terminations := make([]cni.Termination, 0, 10)
 	addresses := make([]cni.Address, 0, 10)
 	routes := make([]cni.Route, 0, 10)
@@ -85,7 +85,7 @@ func CNIConfigForVPCAttachment(vpc galacticv1alpha.VPC, vpcAttachment galacticv1
 				Type:          "galactic",
 				VPC:           vpcIdentifierBase62,
 				VPCAttachment: vpcAttachmentIdentifierBase62,
-				MTU:           1300,
+				MTU:           mtu,
 				Terminations:  terminations,
 				IPAM: cni.IPAM{
 					Type:      "static",

internal/cniconfig/cniconfig_test.go

@@ -21,7 +21,7 @@ func TestCNIConfigForVPCAttachment(t *testing.T) {
 				Type:          "galactic",
 				VPC:           "1hVwxnaA7",
 				VPCAttachment: "h31",
-				MTU:           1300,
+				MTU:           1372,
 				Terminations: []cni.Termination{
 					{Network: "10.1.1.0/24"},
 					{Network: "2001:10:1:1::/64"},
@@ -90,7 +90,7 @@ func TestCNIConfigForVPCAttachment(t *testing.T) {
 			Identifier: "ffff",
 		},
 	}
-	actual, err := cniconfig.CNIConfigForVPCAttachment(vpc, vpcAttachment)
+	actual, err := cniconfig.CNIConfigForVPCAttachment(vpc, vpcAttachment, 1372)
 	if err != nil {
 		t.Errorf("CNIConfigForVPCAttachment error: %+v", err)
 	}

internal/controller/vpcattachment_controller.go

@@ -28,6 +28,7 @@ type VPCAttachmentReconciler struct {
 	client.Client
 	Scheme     *runtime.Scheme
 	Identifier *identifier.Identifier
+	MTU        int
 }
 
 // +kubebuilder:rbac:groups=galactic.datumapis.com,resources=vpcattachments,verbs=get;list;watch;create;update;patch;delete
@@ -82,7 +83,7 @@ func (r *VPCAttachmentReconciler) Reconcile(ctx context.Context, req ctrl.Reques
 		},
 	}
 	_, err := controllerutil.CreateOrUpdate(ctx, r.Client, nad, func() error {
-		cniPluginConfig, err := cniconfig.CNIConfigForVPCAttachment(vpc, vpcAttachment)
+		cniPluginConfig, err := cniconfig.CNIConfigForVPCAttachment(vpc, vpcAttachment, r.MTU)
 		if err != nil {
 			return err
 		}

test/e2e/e2e_test.go

@@ -429,8 +429,8 @@ var _ = Describe("Manager", Ordered, func() {
 						"CNI config should have cniVersion 0.4.0")
 					g.Expect(output).To(ContainSubstring(`"type":"galactic"`),
 						"CNI config should use the galactic plugin")
-					g.Expect(output).To(ContainSubstring(`"mtu":1300`),
-						"CNI config should set MTU to 1300")
+					g.Expect(output).To(ContainSubstring(`"mtu":1372`),
+						"CNI config should set MTU to 1372")
 					g.Expect(output).To(ContainSubstring(`"type":"static"`),
 						"CNI config IPAM should be static")