Data Path Port configuration support

This PR chnages allow user to configure data path
port number. By default we use 4789 port number. But this commit
will allow user to configure port number during swarm init.
Data path port can't be modified after swarm init.

Signed-off-by: selansen <elango.siva@docker.com>

cli/command/swarm/init.go

@@ -20,6 +20,7 @@ type initOptions struct {
 	// Not a NodeAddrOption because it has no default port.
 	advertiseAddr             string
 	dataPathAddr              string
+	dataPathPort              uint32
 	forceNewCluster           bool
 	availability              string
 	defaultAddrPools          []net.IPNet
@@ -45,6 +46,8 @@ func newInitCommand(dockerCli command.Cli) *cobra.Command {
 	flags.StringVar(&opts.advertiseAddr, flagAdvertiseAddr, "", "Advertised address (format: <ip|interface>[:port])")
 	flags.StringVar(&opts.dataPathAddr, flagDataPathAddr, "", "Address or interface to use for data path traffic (format: <ip|interface>)")
 	flags.SetAnnotation(flagDataPathAddr, "version", []string{"1.31"})
+	flags.Uint32Var(&opts.dataPathPort, flagDataPathPort, 0, "Port number to use for data path traffic (1024 - 49151). If no value is set or is set to 0, the default port (4789) is used.")
+	flags.SetAnnotation(flagDataPathPort, "version", []string{"1.40"})
 	flags.BoolVar(&opts.forceNewCluster, "force-new-cluster", false, "Force create a new cluster from current state")
 	flags.BoolVar(&opts.autolock, flagAutolock, false, "Enable manager autolocking (requiring an unlock key to start a stopped manager)")
 	flags.StringVar(&opts.availability, flagAvailability, "active", `Availability of the node ("active"|"pause"|"drain")`)
@@ -74,6 +77,7 @@ func runInit(dockerCli command.Cli, flags *pflag.FlagSet, opts initOptions) erro
 		Spec:             opts.swarmOptions.ToSpec(flags),
 		AutoLockManagers: opts.swarmOptions.autolock,
 		SubnetSize:       opts.DefaultAddrPoolMaskLength,
+		DataPathPort:     opts.dataPathPort,
 	}
 	if flags.Changed(flagAvailability) {
 		availability := swarm.NodeAvailability(strings.ToLower(opts.availability))

cli/command/swarm/opts.go

@@ -22,6 +22,7 @@ const (
 	flagListenAddr                = "listen-addr"
 	flagAdvertiseAddr             = "advertise-addr"
 	flagDataPathAddr              = "data-path-addr"
+	flagDataPathPort              = "data-path-port"
 	flagDefaultAddrPool           = "default-addr-pool"
 	flagDefaultAddrPoolMaskLength = "default-addr-pool-mask-length"
 	flagQuiet                     = "quiet"

cli/command/system/info.go

@@ -235,6 +235,9 @@ func printSwarmInfo(dockerCli command.Cli, info types.Info) {
 			fmt.Fprintln(dockerCli.Out(), " Default Address Pool:", strAddrPool.String())
 			fmt.Fprintln(dockerCli.Out(), " SubnetSize:", info.Swarm.Cluster.SubnetSize)
 		}
+		if info.Swarm.Cluster.DataPathPort > 0 {
+			fmt.Fprintln(dockerCli.Out(), " Data Path Port:", info.Swarm.Cluster.DataPathPort)
+		}
 		fmt.Fprintln(dockerCli.Out(), " Orchestration:")
 
 		taskHistoryRetentionLimit := int64(0)

cli/command/system/testdata/docker-info-with-swarm.golden

@@ -21,6 +21,7 @@ Swarm: active
  ClusterID: 9vs5ygs0gguyyec4iqf2314c0
  Managers: 1
  Nodes: 1
+ Data Path Port: 0
  Orchestration:
   Task History Retention Limit: 5
  Raft:

contrib/completion/bash/docker

@@ -3698,7 +3698,7 @@ _docker_swarm_init() {
 			COMPREPLY=( $( compgen -W "active drain pause" -- "$cur" ) )
 			return
 			;;
-		--cert-expiry|--default-addr-pool|--default-addr-pool-mask-length|--dispatcher-heartbeat|--external-ca|--max-snapshots|--snapshot-interval|--task-history-limit )
+		--cert-expiry|--data-path-port|--default-addr-pool|--default-addr-pool-mask-length|--dispatcher-heartbeat|--external-ca|--max-snapshots|--snapshot-interval|--task-history-limit )
 			return
 			;;
 		--data-path-addr)
@@ -3718,7 +3718,7 @@ _docker_swarm_init() {
 
 	case "$cur" in
 		-*)
-			COMPREPLY=( $( compgen -W "--advertise-addr --autolock --availability --cert-expiry --data-path-addr --default-addr-pool --default-addr-pool-mask-length --dispatcher-heartbeat --external-ca --force-new-cluster --help --listen-addr --max-snapshots --snapshot-interval --task-history-limit" -- "$cur" ) )
+			COMPREPLY=( $( compgen -W "--advertise-addr --autolock --availability --cert-expiry --data-path-addr --data-path-port --default-addr-pool --default-addr-pool-mask-length --dispatcher-heartbeat --external-ca --force-new-cluster --help --listen-addr --max-snapshots --snapshot-interval --task-history-limit " -- "$cur" ) )
 			;;
 	esac
 }

contrib/completion/zsh/_docker

@@ -2285,6 +2285,7 @@ __docker_swarm_subcommand() {
                 $opts_help \
                 "($help)--advertise-addr=[Advertised address]:ip\:port: " \
                 "($help)--data-path-addr=[Data path IP or interface]:ip " \
+                "($help)--data-path-port=[Data Path Port] " \
                 "($help)--default-addr-pool=[Default address pool]" \
                 "($help)--default-addr-pool-mask-length=[Default address pool subnet mask length]" \
                 "($help)--autolock[Enable manager autolocking]" \
@@ -2297,6 +2298,7 @@ __docker_swarm_subcommand() {
                 "($help)--max-snapshots[Number of additional Raft snapshots to retain]" \
                 "($help)--snapshot-interval[Number of log entries between Raft snapshots]" \
                 "($help)--task-history-limit=[Task history retention limit]:limit: " && ret=0
+
             ;;
         (join)
             _arguments $(__docker_arguments) -A '-*' \

docs/reference/commandline/swarm_init.md

@@ -36,6 +36,7 @@ Options:
       --max-snapshots uint              Number of additional Raft snapshots to retain
       --snapshot-interval uint          Number of log entries between Raft snapshots (default 10000)
       --task-history-limit int          Task history retention limit (default 5)
+      --data-path-port uint             Data path port number
 ```
 
 ## Description
@@ -130,6 +131,21 @@ management traffic of the cluster.
 If unspecified, Docker will use the same IP address or interface that is used for the
 advertise address.
 
+### `--data-path-port`
+
+This flag specifies data path port number to use for data path traffic (1024 - 49151).
+If no value is set or is set to 0, the default port (4789) is used. This value is set for per cluster
+so the option is supported only via swarm init command. swarm update or swarm join commands do not support
+this option. The port is reserved for UDP traffic.
+Format example is `docker swarm init --data-path-addr=20.20.20.1 --data-path-port=7777`
+
+Docker info output will display currently used port for data path traffic.
+ Docker info #
+  ClusterID: 9vs5ygs0gguyyec4iqf2314c0
+  Managers: 1
+  Nodes: 1
+  Data Path Port: 7777
+
 ### `--default-addr-pool`
 This flag specifies default subnet pools for global scope networks.
 Format example is `--default-addr-pool 30.30.0.0/16 --default-addr-pool 40.40.0.0/16`