fix: allow dynamic ports for API only in non-distributed setups (#18019)

fixes #17998

cmd/common-main.go

@@ -391,7 +391,7 @@ func handleCommonCmdArgs(ctx *cli.Context) {
 	if consoleAddr == "" {
 		p, err := xnet.GetFreePort()
 		if err != nil {
-			logger.FatalIf(err, "Unable to get free port for console on the host")
+			logger.FatalIf(err, "Unable to get free port for Console UI on the host")
 		}
 		consoleAddr = net.JoinHostPort("", p.String())
 	}
@@ -405,6 +405,15 @@ func handleCommonCmdArgs(ctx *cli.Context) {
 	}
 
 	globalMinioHost, globalMinioPort = mustSplitHostPort(addr)
+	if globalMinioPort == "0" {
+		p, err := xnet.GetFreePort()
+		if err != nil {
+			logger.FatalIf(err, "Unable to get free port for S3 API on the host")
+		}
+		globalMinioPort = p.String()
+		globalDynamicAPIPort = true
+	}
+
 	globalMinioConsoleHost, globalMinioConsolePort = mustSplitHostPort(consoleAddr)
 
 	if globalMinioPort == globalMinioConsolePort {

cmd/globals.go

@@ -402,6 +402,9 @@ var (
 
 	// Captures all batch jobs metrics globally
 	globalBatchJobsMetrics batchJobMetrics
+
+	// Indicates if server was started as `--address ":0"`
+	globalDynamicAPIPort bool
 	// Add new variable global values here.
 )
 

cmd/server-main.go

@@ -255,6 +255,16 @@ func serverHandleCmdArgs(ctx *cli.Context) {
 	logger.FatalIf(err, "Invalid command line arguments")
 	globalNodes = globalEndpoints.GetNodes()
 
+	globalIsErasure = (setupType == ErasureSetupType)
+	globalIsDistErasure = (setupType == DistErasureSetupType)
+	if globalIsDistErasure {
+		globalIsErasure = true
+	}
+	globalIsErasureSD = (setupType == ErasureSDSetupType)
+	if globalDynamicAPIPort && globalIsDistErasure {
+		logger.FatalIf(errInvalidArgument, "Invalid --address=\"%s\", port '0' is not allowed in a distributed erasure coded setup", ctx.String("address"))
+	}
+
 	globalLocalNodeName = GetLocalPeer(globalEndpoints, globalMinioHost, globalMinioPort)
 	nodeNameSum := sha256.Sum256([]byte(globalLocalNodeName))
 	globalLocalNodeNameHex = hex.EncodeToString(nodeNameSum[:])
@@ -289,13 +299,6 @@ func serverHandleCmdArgs(ctx *cli.Context) {
 	// To avoid this error situation we check for port availability.
 	logger.FatalIf(xhttp.CheckPortAvailability(globalMinioHost, globalMinioPort, globalTCPOptions), "Unable to start the server")
 
-	globalIsErasure = (setupType == ErasureSetupType)
-	globalIsDistErasure = (setupType == DistErasureSetupType)
-	if globalIsDistErasure {
-		globalIsErasure = true
-	}
-	globalIsErasureSD = (setupType == ErasureSDSetupType)
-
 	globalConnReadDeadline = ctx.Duration("conn-read-deadline")
 	globalConnWriteDeadline = ctx.Duration("conn-write-deadline")
 }