diff --git a/config/disk.go b/config/disk.go
index ab54a91e..dd3ddf9e 100755
--- a/config/disk.go
+++ b/config/disk.go
@@ -1,7 +1,9 @@
 package config
 
 import (
+	"encoding/json"
 	"io/ioutil"
+	"net"
 	"os"
 	"path"
 	"path/filepath"
@@ -125,6 +127,30 @@ func SaveInitCmdline(cmdLineArgs string) {
 	}
 }
 
+func SaveCNISubnet(subnet, filename string) {
+	if _, _, err := net.ParseCIDR(subnet); err != nil {
+		log.Errorf("Failed to parse system-docker subnet from cmdline: %v", err)
+	}
+	rBytes, err := ioutil.ReadFile(filename)
+	if err != nil {
+		log.Errorf("Failed to read from %s: %v", filename, err)
+	}
+	var data map[string]interface{}
+	if err = json.Unmarshal(rBytes, &data); err != nil {
+		log.Errorf("Failed to pasre json: %v", err)
+	}
+	ipam := data["ipam"].(map[string]interface{})
+	ipam["subnet"] = subnet
+	wBytes, err := json.MarshalIndent(data, "", "\t")
+	if err != nil {
+		log.Errorf("Failed to convert to bytes: %v", err)
+	}
+	log.Debugf("New cni bridge conf: %s", wBytes)
+	if err = ioutil.WriteFile(filename, wBytes, 0644); err != nil {
+		log.Errorf("Failed to write cni bridge file %s: %v", filename, err)
+	}
+}
+
 func CloudConfigDirFiles(dirPrefix string) []string {
 	cloudConfigDir := path.Join(dirPrefix, CloudConfigDir)
 
diff --git a/config/types.go b/config/types.go
index ef3428a5..064705ad 100755
--- a/config/types.go
+++ b/config/types.go
@@ -47,6 +47,9 @@ const (
 	MetaDataFile           = "/var/lib/rancher/conf/metadata"
 	CloudConfigFile        = "/var/lib/rancher/conf/cloud-config.yml"
 	EtcResolvConfFile      = "/etc/resolv.conf"
+	CNIBridgeConfigFile    = "/etc/docker/cni/bridge.d/bridge.conf"
+
+	RKPDockerSysBridgeSubnet = "rancher.system_docker.subnet"
 )
 
 var (
diff --git a/init/init.go b/init/init.go
index 6c645ef8..24343881 100755
--- a/init/init.go
+++ b/init/init.go
@@ -14,6 +14,7 @@ import (
 
 	"github.com/docker/docker/pkg/mount"
 	"github.com/rancher/os/config"
+	"github.com/rancher/os/config/cmdline"
 	"github.com/rancher/os/dfs"
 	"github.com/rancher/os/log"
 	"github.com/rancher/os/util"
@@ -428,6 +429,12 @@ func RunInit() error {
 			log.FsReady()
 			log.Debugf("WARNING: switchroot and mount OEM2 phases not written to log file")
 
+			// update docker-sys bridge setting
+			if dockerSysSubnet := cmdline.GetCmdline(config.RKPDockerSysBridgeSubnet); dockerSysSubnet != "" {
+				val := dockerSysSubnet.(string)
+				config.SaveCNISubnet(val, config.CNIBridgeConfigFile)
+			}
+
 			return cfg, nil
 		}},
 		config.CfgFuncData{"b2d Env", func(cfg *config.CloudConfig) (*config.CloudConfig, error) {