rkt-kubernetes bridge CNI patch

patch.diff

diff --git a/pkg/kubelet/kubelet.go b/pkg/kubelet/kubelet.go
index 713748a..a37b949 100644
--- a/pkg/kubelet/kubelet.go
+++ b/pkg/kubelet/kubelet.go
@@ -2599,7 +2599,11 @@ func (kl *Kubelet) reconcileCBR0(podCIDR string) error {
 		glog.V(5).Info("Shaper is nil, creating")
 		kl.shaper = bandwidth.NewTCShaper("cbr0")
 	}
-	return kl.shaper.ReconcileInterface()
+	if err := kl.shaper.ReconcileInterface(); err != nil {
+		return err
+	}
+
+	return rkt.WriteBridgeNetConfig("cbr0", cidr)
 }
 
 // updateNodeStatus updates node status to master with retries.
diff --git a/pkg/kubelet/rkt/network.go b/pkg/kubelet/rkt/network.go
new file mode 100644
index 0000000..c388dcc
--- /dev/null
+++ b/pkg/kubelet/rkt/network.go
@@ -0,0 +1,73 @@
+/*
+Copyright 2015 The Kubernetes Authors All rights reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package rkt
+
+import (
+	"encoding/json"
+	"io/ioutil"
+	"net"
+	"os"
+	"path"
+)
+
+const (
+	defaultNetConfigFile = "k8s-cbr0.conf"
+	defaultNetworkName   = "rkt.kubernetes.io"
+)
+
+type IPAM struct {
+	Type    string `json:"type"`
+	Subnet  string `json:"subnet"`
+	Gateway net.IP `json:"gateway"`
+}
+
+// A CNI bridge config that instructs rkt to get IPs from the 'cbr0' bridge
+// created by kubelet.
+type NetConfig struct {
+	Name   string `json:"name"`
+	Type   string `json:"type"`
+	BrName string `json:"bridge"`
+	IsGW   bool   `json:"isGateway"`
+	IPAM   IPAM   `json:"ipam"`
+}
+
+// WriteBridgeNetConfig creates and write the CNI bridge configure file at ${rktLocalConfigDir}/net.d/${defaultNetConfigFile}.
+// bridgeName is the name of the container bridge, e.g. 'cbr0'.
+// cidr is the CIDR block of the bridge, note that cidr.IP is the gateway of the bridge.
+func WriteBridgeNetConfig(bridgeName string, cidr *net.IPNet) error {
+	netConfig := &NetConfig{
+		Name:   defaultNetworkName,
+		Type:   "bridge",
+		BrName: bridgeName,
+		IsGW:   true,
+		IPAM:   IPAM{Type: "host-local", Subnet: cidr.String(), Gateway: cidr.IP},
+	}
+
+	data, err := json.MarshalIndent(netConfig, "", "\t")
+	if err != nil {
+		return err
+	}
+
+	// Ensure the 'net.d' dir exists.
+	dirpath := path.Join(rktLocalConfigDir, "net.d")
+	err = os.MkdirAll(dirpath, 0750)
+	if err != nil && !os.IsExist(err) {
+		return err
+	}
+
+	return ioutil.WriteFile(path.Join(dirpath, defaultNetConfigFile), data, 0640)
+}