Add --flannel-conf flag

pkg/agent/config/config.go

@@ -362,7 +362,12 @@ func get(envInfo *cmds.Agent) (*config.Node, error) {
 	nodeConfig.ServerAddress = serverURLParsed.Host
 	nodeConfig.Certificate = servingCert
 	if !nodeConfig.NoFlannel {
-		nodeConfig.FlannelConf = filepath.Join(envInfo.DataDir, "etc/flannel/net-conf.json")
+		if envInfo.FlannelConf == "" {
+			nodeConfig.FlannelConf = filepath.Join(envInfo.DataDir, "etc/flannel/net-conf.json")
+		} else {
+			nodeConfig.FlannelConf = envInfo.FlannelConf
+			nodeConfig.FlannelConfOverride = true
+		}
 		nodeConfig.AgentConfig.CNIBinDir = filepath.Dir(hostLocal)
 		nodeConfig.AgentConfig.CNIConfDir = filepath.Join(envInfo.DataDir, "etc/cni/net.d")
 	}

pkg/agent/flannel/setup.go

@@ -98,6 +98,10 @@ func createFlannelConf(config *config.Node) error {
 	if config.FlannelConf == "" {
 		return nil
 	}
+	if config.FlannelConfOverride {
+		logrus.Infof("Using custom flannel conf defined at %s", config.FlannelConf)
+		return nil
+	}
 	return util.WriteFile(config.FlannelConf,
 		strings.Replace(netJSON, "%CIDR%", config.AgentConfig.ClusterCIDR.String(), -1))
 }

pkg/cli/cmds/agent.go

@@ -22,6 +22,7 @@ type Agent struct {
 	ContainerRuntimeEndpoint string
 	NoFlannel                bool
 	FlannelIface             string
+	FlannelConf              string
 	Debug                    bool
 	Rootless                 bool
 	AgentShared
@@ -64,6 +65,11 @@ var (
 		Usage:       "(agent) Override default flannel interface",
 		Destination: &AgentConfig.FlannelIface,
 	}
+	FlannelConfFlag = cli.StringFlag{
+		Name:        "flannel-conf",
+		Usage:       "(agent) Override default flannel config file",
+		Destination: &AgentConfig.FlannelConf,
+	}
 	CRIEndpointFlag = cli.StringFlag{
 		Name:        "container-runtime-endpoint",
 		Usage:       "(agent) Disable embedded containerd and use alternative CRI implementation",
@@ -151,6 +157,7 @@ func NewAgentCommand(action func(ctx *cli.Context) error) cli.Command {
 			DockerFlag,
 			FlannelFlag,
 			FlannelIfaceFlag,
+			FlannelConfFlag,
 			NodeNameFlag,
 			NodeIPFlag,
 			CRIEndpointFlag,

pkg/cli/cmds/server.go

@@ -194,6 +194,7 @@ func NewServerCommand(action func(*cli.Context) error) cli.Command {
 			DockerFlag,
 			FlannelFlag,
 			FlannelIfaceFlag,
+			FlannelConfFlag,
 			CRIEndpointFlag,
 			PauseImageFlag,
 			ResolvConfFlag,

pkg/daemons/config/types.go

@@ -18,6 +18,7 @@ type Node struct {
 	ContainerRuntimeEndpoint string
 	NoFlannel                bool
 	FlannelConf              string
+	FlannelConfOverride      bool
 	FlannelIface             *net.Interface
 	Containerd               Containerd
 	Images                   string