Use random host from among multiple hosts to create requests

Also use hosts passed to Minio startup command to populate IP
addresses if MINIO_PUBLIC_IPS is not set.

cmd/endpoint.go

@@ -20,6 +20,7 @@ import (
 	"fmt"
 	"net"
 	"net/url"
+	"os"
 	"path"
 	"path/filepath"
 	"runtime"
@@ -442,6 +443,8 @@ func CreateEndpoints(serverAddr string, args ...[]string) (string, EndpointList,
 		return serverAddr, endpoints, setupType, err
 	}
 
+	updateDomainIPs(uniqueArgs)
+
 	setupType = DistXLSetupType
 	return serverAddr, endpoints, setupType, nil
 }
@@ -493,3 +496,22 @@ func GetRemotePeers(endpoints EndpointList) []string {
 
 	return peerSet.ToSlice()
 }
+
+// In federated and distributed setup, update IP addresses of the hosts passed in command line
+// if MINIO_PUBLIC_IPS are not set manually
+func updateDomainIPs(endPoints set.StringSet) {
+	_, dok := os.LookupEnv("MINIO_DOMAIN")
+	_, eok := os.LookupEnv("MINIO_ETCD_ENDPOINTS")
+	_, iok := os.LookupEnv("MINIO_PUBLIC_IPS")
+	if dok && eok && !iok {
+		globalDomainIPs = set.NewStringSet()
+		for e := range endPoints {
+			host, _, _ := net.SplitHostPort(e)
+			ipList, _ := getHostIP4(host)
+			remoteIPList := ipList.FuncMatch(func(ip string, matchString string) bool {
+				return !strings.HasPrefix(ip, "127.")
+			}, "")
+			globalDomainIPs.Add(remoteIPList.ToSlice()[0])
+		}
+	}
+}