main.go: add the "net-config-path" flag

Add the flag "net-config-path" that holds the path
for the network configuration.

Set the default value to "/etc/kube-flannel/net-conf.json".

Signed-off-by: Lubomir I. Ivanov <lubomirivanov@vmware.com>

Documentation/configuration.md

@@ -58,6 +58,7 @@ The following configuration illustrates the use of most options with `udp` backe
 --iface-regex="": regex expression to match the first interface to use (IP or name) for inter-host communication. If unspecified, will default to the interface for the default route on the machine. This can be specified multiple times to check each regex in order. Returns the first match found. This option is superseded by the iface option and will only be used if nothing matches any option specified in the iface options.
 --iptables-resync=5: resync period for iptables rules, in seconds. Defaults to 5 seconds, if you see a large amount of contention for the iptables lock increasing this will probably help.
 --subnet-file=/run/flannel/subnet.env: filename where env variables (subnet and MTU values) will be written to.
+--net-config-path=/etc/kube-flannel/net-conf.json: path to the network configuration file to use
 --subnet-lease-renew-margin=60: subnet lease renewal margin, in minutes.
 --ip-masq=false: setup IP masquerade for traffic destined for outside the flannel network. Flannel assumes that the default policy is ACCEPT in the NAT POSTROUTING chain.
 -v=0: log level for V logs. Set to 1 to see messages related to data path.

main.go

@@ -98,6 +98,7 @@ type CmdLineOpts struct {
 	charonViciUri          string
 	iptablesResyncSeconds  int
 	iptablesForwardRules   bool
+	netConfPath            string
 }
 
 var (
@@ -130,6 +131,7 @@ func init() {
 	flannelFlags.IntVar(&opts.healthzPort, "healthz-port", 0, "the port for healthz server to listen(0 to disable)")
 	flannelFlags.IntVar(&opts.iptablesResyncSeconds, "iptables-resync", 5, "resync period for iptables rules, in seconds")
 	flannelFlags.BoolVar(&opts.iptablesForwardRules, "iptables-forward-rules", true, "add default accept rules to FORWARD chain in iptables")
+	flannelFlags.StringVar(&opts.netConfPath, "net-config-path", "/etc/kube-flannel/net-conf.json", "path to the network configuration file")
 
 	// glog will log to tmp files by default. override so all entries
 	// can flow into journald (if running under systemd)
@@ -159,7 +161,7 @@ func usage() {
 
 func newSubnetManager() (subnet.Manager, error) {
 	if opts.kubeSubnetMgr {
-		return kube.NewSubnetManager(opts.kubeApiUrl, opts.kubeConfigFile, opts.kubeAnnotationPrefix)
+		return kube.NewSubnetManager(opts.kubeApiUrl, opts.kubeConfigFile, opts.kubeAnnotationPrefix, opts.netConfPath)
 	}
 
 	cfg := &etcdv2.EtcdConfig{
@@ -349,7 +351,7 @@ func recycleIPTables(nw ip.IP4Net, lease *subnet.Lease) error {
 	prevNetwork := ReadCIDRFromSubnetFile(opts.subnetFile, "FLANNEL_NETWORK")
 	prevSubnet := ReadCIDRFromSubnetFile(opts.subnetFile, "FLANNEL_SUBNET")
 	// recycle iptables rules only when network configured or subnet leased is not equal to current one.
-	if prevNetwork != nw && prevSubnet != lease.Subnet{
+	if prevNetwork != nw && prevSubnet != lease.Subnet {
 		log.Infof("Current network or subnet (%v, %v) is not equal to previous one (%v, %v), trying to recycle old iptables rules", nw, lease.Subnet, prevNetwork, prevSubnet)
 		lease := &subnet.Lease{
 			Subnet: prevSubnet,

subnet/kube/kube.go

@@ -50,8 +50,6 @@ var (
 const (
 	resyncPeriod              = 5 * time.Minute
 	nodeControllerSyncTimeout = 10 * time.Minute
-
-	netConfPath = "/etc/kube-flannel/net-conf.json"
 )
 
 type kubeSubnetManager struct {
@@ -64,7 +62,7 @@ type kubeSubnetManager struct {
 	events         chan subnet.Event
 }
 
-func NewSubnetManager(apiUrl, kubeconfig, prefix string) (subnet.Manager, error) {
+func NewSubnetManager(apiUrl, kubeconfig, prefix, netConfPath string) (subnet.Manager, error) {
 
 	var cfg *rest.Config
 	var err error