added known nodes info in CLUSTER INFO

src/cluster.c

@@ -1192,11 +1192,13 @@ void clusterCommand(redisClient *c) {
             "cluster_slots_ok:%d\r\n"
             "cluster_slots_pfail:%d\r\n"
             "cluster_slots_fail:%d\r\n"
+            "cluster_known_nodes:%lu\r\n"
             , statestr[server.cluster.state],
             slots_assigned,
             slots_ok,
             slots_pfail,
-            slots_fail
+            slots_fail,
+            dictSize(server.cluster.nodes)
         );
         addReplySds(c,sdscatprintf(sdsempty(),"$%lu\r\n",
             (unsigned long)sdslen(info)));