Make Weave MTU configurable with default config for jumbo frames

cmd/kops/create_cluster.go

@@ -367,7 +367,10 @@ func RunCreateCluster(f *util.Factory, out io.Writer, c *CreateClusterOptions) e
 	case "kopeio-vxlan", "kopeio":
 		cluster.Spec.Networking.Kopeio = &api.KopeioNetworkingSpec{}
 	case "weave":
-		cluster.Spec.Networking.Weave = &api.WeaveNetworkingSpec{}
+		// AWS supports "jumbo frames" of 9001 bytes and weave adds up to 87 bytes overhead
+		// sets the default to the largest number that leaves enough overhead and is divisible by 4
+		jumboFrameMTUSize := int32(8912)
+		cluster.Spec.Networking.Weave = &api.WeaveNetworkingSpec{MTU: &jumboFrameMTUSize}
 	case "flannel":
 		cluster.Spec.Networking.Flannel = &api.FlannelNetworkingSpec{}
 	case "calico":

docs/networking.md

@@ -3,10 +3,16 @@
 Kubernetes Operations (kops) currently supports 4 networking modes:
 
 * `kubenet` kubernetes native networking via a CNI plugin.  This is the default.
-* `cni` Container Network Interface(CNI) style networking, often installed via a Daemonset.
+* `cni` Container Network Interface(CNI) style networking, often installed via a Daemonset. Kops can configure
+ several CNI networking providers out of the box, detailed below.
 * `classic` kubernetes native networking, done in-process.
 * `external` networking is done via a Daemonset. This is used in some custom implementations.
 
+You are able to specify your networking type via command line switch or in your yaml file.
+The `--networking` option accepts one of the four values above, or one of the supported CNI options given below.
+
+If `--networking` is left undefined `kubenet` is installed.
+
 ### kops Default Networking
 
 Kubernetes Operations (kops) uses `kubenet` networking by default. This sets up networking on AWS using VPC
@@ -62,17 +68,11 @@ CNI networking providers are not part of the Kubernetes project, we do not maint
 their installation processes.  With that in mind, we do not support problems with
 different CNI providers but support configuring Kubernetes to run CNI providers.
 
-## Specifying network option for cluster creation
-
-You are able to specify your networking type via command line switch or in your yaml file.
-The `--networking` option accepts the three different values defined above: `kubenet`, `cni`,
-`classic`, and `external`. If `--networking` is left undefined `kubenet` is installed.
-
 ### Weave Example for CNI
 
-#### Installation Weave on a new Cluster
+#### Installing Weave on a new Cluster
 
-The following command sets up a cluster, in HA mode, that is ready for a CNI installation.
+The following command sets up a cluster, in HA mode, with Weave as the CNI and networking policy provider:
 
 ```console
 $ export $ZONE=mylistofzones
@@ -81,21 +81,24 @@ $ kops create cluster \
   --master-zones $ZONES \
   --master-size m4.large \
   --node-size m4.large \
-  --networking cni \
+  --networking weave \
   --yes \
   --name myclustername.mydns.io
 ```
 
-Once the cluster is stable, which you can check with a `kubectl cluster-info` command, the next
-step is to install CNI networking. Most of the CNI network providers are
-moving to installing their components plugins via a Daemonset.  For instance weave will
-install with the following command:
+The above daemonset installation requires K8s 1.4.x or above.
+
+#### Configuring Weave MTU
 
-```console
-$ kubectl create -f https://git.io/weave-kube
-```
+The default configuration for Weave sets the MTU size to support jumbo frames (which AWS VPC supports).
+To change the default configuration, edit the cluster with `kops edit cluster <name>` and update `mtu`.
 
-The above daemonset installation requires K8s 1.4.x or above.
+```
+spec:
+  networking:
+    weave:
+      mtu: 8912
+```
 
 ### Calico Example for CNI and Network Policy
 

pkg/apis/kops/networking.go

@@ -54,6 +54,7 @@ type KopeioNetworkingSpec struct {
 
 // Weave declares that we want Weave networking
 type WeaveNetworkingSpec struct {
+	MTU *int32 `json:"mtu,omitempty"`
 }
 
 // Flannel declares that we want Flannel networking

pkg/apis/kops/v1alpha1/networking.go

@@ -54,6 +54,7 @@ type KopeioNetworkingSpec struct {
 
 // Weave declares that we want Weave networking
 type WeaveNetworkingSpec struct {
+	MTU *int32 `json:"mtu,omitempty"`
 }
 
 // Flannel declares that we want Flannel networking

pkg/apis/kops/v1alpha1/zz_generated.conversion.go

@@ -1765,6 +1765,7 @@ func Convert_kops_RBACAuthorizationSpec_To_v1alpha1_RBACAuthorizationSpec(in *ko
 }
 
 func autoConvert_v1alpha1_WeaveNetworkingSpec_To_kops_WeaveNetworkingSpec(in *WeaveNetworkingSpec, out *kops.WeaveNetworkingSpec, s conversion.Scope) error {
+	out.MTU = in.MTU
 	return nil
 }
 
@@ -1773,6 +1774,7 @@ func Convert_v1alpha1_WeaveNetworkingSpec_To_kops_WeaveNetworkingSpec(in *WeaveN
 }
 
 func autoConvert_kops_WeaveNetworkingSpec_To_v1alpha1_WeaveNetworkingSpec(in *kops.WeaveNetworkingSpec, out *WeaveNetworkingSpec, s conversion.Scope) error {
+	out.MTU = in.MTU
 	return nil
 }
 

pkg/apis/kops/v1alpha2/networking.go

@@ -54,6 +54,7 @@ type KopeioNetworkingSpec struct {
 
 // Weave declares that we want Weave networking
 type WeaveNetworkingSpec struct {
+	MTU *int32 `json:"mtu,omitempty"`
 }
 
 // Flannel declares that we want Flannel networking

pkg/apis/kops/v1alpha2/zz_generated.conversion.go

@@ -1919,6 +1919,7 @@ func Convert_kops_TopologySpec_To_v1alpha2_TopologySpec(in *kops.TopologySpec, o
 }
 
 func autoConvert_v1alpha2_WeaveNetworkingSpec_To_kops_WeaveNetworkingSpec(in *WeaveNetworkingSpec, out *kops.WeaveNetworkingSpec, s conversion.Scope) error {
+	out.MTU = in.MTU
 	return nil
 }
 
@@ -1927,6 +1928,7 @@ func Convert_v1alpha2_WeaveNetworkingSpec_To_kops_WeaveNetworkingSpec(in *WeaveN
 }
 
 func autoConvert_kops_WeaveNetworkingSpec_To_v1alpha2_WeaveNetworkingSpec(in *kops.WeaveNetworkingSpec, out *WeaveNetworkingSpec, s conversion.Scope) error {
+	out.MTU = in.MTU
 	return nil
 }
 

upup/models/cloudup/resources/addons/networking.weave/k8s-1.6.yaml → upup/models/cloudup/resources/addons/networking.weave/k8s-1.6.yaml.template

@@ -97,6 +97,11 @@ spec:
             limits:
               cpu: 100m
               memory: 200Mi
+          env:
+            - name: IPALLOC_RANGE
+              value: {{ .NonMasqueradeCIDR }}
+            - name: WEAVE_MTU
+              value: "{{ .Networking.Weave.MTU }}"
         - name: weave-npc
           image: weaveworks/weave-npc:1.9.4
           resources:
@@ -108,6 +113,11 @@ spec:
               memory: 200Mi
           securityContext:
             privileged: true
+          env:
+            - name: IPALLOC_RANGE
+              value: {{ .NonMasqueradeCIDR }}
+            - name: WEAVE_MTU
+              value: "{{ .Networking.Weave.MTU }}"
       restartPolicy: Always
       tolerations:
       - key: node-role.kubernetes.io/master

upup/models/cloudup/resources/addons/networking.weave/pre-k8s-1.6.yaml → upup/models/cloudup/resources/addons/networking.weave/pre-k8s-1.6.yaml.template

@@ -58,6 +58,11 @@ spec:
             limits:
               cpu: 100m
               memory: 200Mi
+          env:
+            - name: IPALLOC_RANGE
+              value: {{ .NonMasqueradeCIDR }}
+            - name: WEAVE_MTU
+              value: "{{ .Networking.Weave.MTU }}"
         - name: weave-npc
           image: weaveworks/weave-npc:1.9.4
           resources:
@@ -69,6 +74,11 @@ spec:
               memory: 200Mi
           securityContext:
             privileged: true
+          env:
+            - name: IPALLOC_RANGE
+              value: {{ .NonMasqueradeCIDR }}
+            - name: WEAVE_MTU
+              value: "{{ .Networking.Weave.MTU }}"
       restartPolicy: Always
       volumes:
         - name: weavedb