Cluster Manager: add-node command.

src/redis-cli.c

@@ -165,6 +165,7 @@ typedef struct clusterManagerCommand {
     char *from;
     char *to;
     char **weight;
+    char *master_id;
     int weight_argc;
     int slots;
     int timeout;
@@ -1299,6 +1300,8 @@ static int parseOptions(int argc, char **argv) {
             usage();
         } else if (!strcmp(argv[i],"--cluster-replicas") && !lastarg) {
             config.cluster_manager_command.replicas = atoi(argv[++i]);  
+        } else if (!strcmp(argv[i],"--cluster-master-id") && !lastarg) {
+            config.cluster_manager_command.master_id = argv[++i];  
         } else if (!strcmp(argv[i],"--cluster-from") && !lastarg) {
             config.cluster_manager_command.from = argv[++i];  
         } else if (!strcmp(argv[i],"--cluster-to") && !lastarg) {
@@ -1335,6 +1338,9 @@ static int parseOptions(int argc, char **argv) {
         } else if (!strcmp(argv[i],"--cluster-copy")) {
             config.cluster_manager_command.flags |= 
                 CLUSTER_MANAGER_CMD_FLAG_COPY;  
+        } else if (!strcmp(argv[i],"--cluster-slave")) {
+            config.cluster_manager_command.flags |= 
+                CLUSTER_MANAGER_CMD_FLAG_SLAVE;  
         } else if (!strcmp(argv[i],"--cluster-use-empty-masters")) {
             config.cluster_manager_command.flags |= 
                 CLUSTER_MANAGER_CMD_FLAG_EMPTYMASTER;  
@@ -1847,6 +1853,8 @@ static clusterManagerNode *clusterManagerNodeByName(const char *name);
 static clusterManagerNode *clusterManagerNodeByAbbreviatedName(const char *n);
 static void clusterManagerNodeResetSlots(clusterManagerNode *node);
 static int clusterManagerNodeIsCluster(clusterManagerNode *node, char **err);
+static void clusterManagerPrintNotClusterNodeError(clusterManagerNode *node,
+                                                   char *err); 
 static int clusterManagerNodeLoadInfo(clusterManagerNode *node, int opts,
                                       char **err);
 static int clusterManagerLoadInfoFromNode(clusterManagerNode *node, int opts);
@@ -1875,6 +1883,7 @@ static void clusterManagerNodeArrayAdd(clusterManagerNodeArray *array,
 /* Cluster Manager commands. */
 
 static int clusterManagerCommandCreate(int argc, char **argv);
+static int clusterManagerCommandAddNode(int argc, char **argv);
 static int clusterManagerCommandInfo(int argc, char **argv);
 static int clusterManagerCommandCheck(int argc, char **argv);
 static int clusterManagerCommandFix(int argc, char **argv);
@@ -1895,6 +1904,8 @@ typedef struct clusterManagerCommandDef {
 clusterManagerCommandDef clusterManagerCommands[] = {
     {"create", clusterManagerCommandCreate, -2, "host1:port1 ... hostN:portN", 
      "replicas <arg>"},
+    {"add-node", clusterManagerCommandAddNode, 2, 
+     "new_host:new_port existing_host:existing_port", "slave,master-id <arg>"},
     {"check", clusterManagerCommandCheck, -1, "host:port", NULL},
     {"fix", clusterManagerCommandFix, -1, "host:port", NULL},
     {"info", clusterManagerCommandInfo, -1, "host:port", NULL},
@@ -3030,8 +3041,7 @@ static int clusterManagerLoadInfoFromNode(clusterManagerNode *node, int opts) {
     opts |= CLUSTER_MANAGER_OPT_GETFRIENDS;
     char *e = NULL;
     if (!clusterManagerNodeIsCluster(node, &e)) {
-        char *msg = (e ? e : "is not configured as a cluster node.");
+        clusterManagerPrintNotClusterNodeError(node, e);
-        clusterManagerLogErr("[ERR] Node %s:%d %s\n",node->ip,node->port,msg);
         if (e) zfree(e);
         freeClusterManagerNode(node);
         return 0;
@@ -3313,6 +3323,27 @@ static clusterManagerNode * clusterManagerGetNodeWithMostKeysInSlot(list *nodes,
     return node;
 }
 
+/* This function returns the master that has the least number of replicas
+ * in the cluster. If there are multiple masters with the same smaller
+ * number of replicas, one at random is returned. */
+
+static clusterManagerNode *clusterManagerNodeWithLeastReplicas() {
+    clusterManagerNode *node = NULL;
+    int lowest_count = 0;
+    listIter li;
+    listNode *ln;
+    listRewind(cluster_manager.nodes, &li);
+    while ((ln = listNext(&li)) != NULL) {
+        clusterManagerNode *n = ln->value;
+        if (node->flags & CLUSTER_MANAGER_FLAG_SLAVE) continue;
+        if (node == NULL || n->replicas_count < lowest_count) {
+            node = n;
+            lowest_count = n->replicas_count;
+        }
+    }
+    return node;
+}
+
 static int clusterManagerFixSlotsCoverage(char *all_slots) {
     int i, fixed = 0;
     list *none = NULL, *single = NULL, *multi = NULL;
@@ -3966,6 +3997,26 @@ static void clusterManagerNodeArrayAdd(clusterManagerNodeArray *array,
     array->nodes[array->count++] = node;
 }
 
+static void clusterManagerPrintNotEmptyNodeError(clusterManagerNode *node, 
+                                                 char *err) 
+{
+    char *msg; 
+    if (err) msg = err;
+    else {
+        msg = "is not empty. Either the node already knows other "
+              "nodes (check with CLUSTER NODES) or contains some "
+              "key in database 0.";
+    }
+    clusterManagerLogErr("[ERR] Node %s:%d %s\n", node->ip, node->port, msg);
+}
+
+static void clusterManagerPrintNotClusterNodeError(clusterManagerNode *node, 
+                                                   char *err) 
+{
+    char *msg = (err ? err : "is not configured as a cluster node.");
+    clusterManagerLogErr("[ERR] Node %s:%d %s\n", node->ip, node->port, msg);
+}
+
 /* Execute redis-cli in Cluster Manager mode */
 static void clusterManagerMode(clusterManagerCommandProc *proc) {
     int argc = config.cluster_manager_command.argc;
@@ -4008,8 +4059,7 @@ static int clusterManagerCommandCreate(int argc, char **argv) {
         }
         char *err = NULL;
         if (!clusterManagerNodeIsCluster(node, &err)) {
-            char *msg = (err ? err : "is not configured as a cluster node.");
+            clusterManagerPrintNotClusterNodeError(node, err);
-            clusterManagerLogErr("[ERR] Node %s:%d %s\n", ip, port, msg);
             if (err) zfree(err);
             freeClusterManagerNode(node);
             return 0;
@@ -4025,14 +4075,7 @@ static int clusterManagerCommandCreate(int argc, char **argv) {
         }
         err = NULL;
         if (!clusterManagerNodeIsEmpty(node, &err)) {
-            char *msg; 
+            clusterManagerPrintNotEmptyNodeError(node, err);
-            if (err) msg = err;
-            else {
-                msg = "is not empty. Either the node already knows other "
-                      "nodes (check with CLUSTER NODES) or contains some "
-                      "key in database 0.";
-            }
-            clusterManagerLogErr("[ERR] Node %s:%d %s\n", ip, port, msg);
             if (err) zfree(err);
             freeClusterManagerNode(node);
             return 0;
@@ -4263,6 +4306,104 @@ cleanup:
     return success;
 }
 
+static int clusterManagerCommandAddNode(int argc, char **argv) {
+    int success = 1;
+    redisReply *reply = NULL;
+    char *ref_ip = NULL, *ip = NULL;
+    int ref_port = 0, port = 0;
+    if (!getClusterHostFromCmdArgs(argc - 1, argv + 1, &ref_ip, &ref_port)) 
+        goto invalid_args;
+    if (!getClusterHostFromCmdArgs(1, argv, &ip, &port))
+        goto invalid_args;
+    clusterManagerLogInfo(">>> Adding node %s:%d to cluster %s:%d\n", ip, port, 
+                          ref_ip, ref_port);
+    // Check the existing cluster
+    clusterManagerNode *refnode = clusterManagerNewNode(ref_ip, ref_port);
+    if (!clusterManagerLoadInfoFromNode(refnode, 0)) return 0;
+    if (!clusterManagerCheckCluster(0)) return 0;
+
+    /* If --cluster-master-id was specified, try to resolve it now so that we
+     * abort before starting with the node configuration. */
+    clusterManagerNode *master_node = NULL;
+    if (config.cluster_manager_command.flags & CLUSTER_MANAGER_CMD_FLAG_SLAVE) {
+        char *master_id = config.cluster_manager_command.master_id;
+        if (master_id != NULL) {
+            master_node = clusterManagerNodeByName(master_id);
+            if (master_node == NULL) {
+                clusterManagerLogErr("[ERR] No such master ID %s\n", master_id);
+                return 0;
+            }
+        } else {
+            master_node = clusterManagerNodeWithLeastReplicas();
+            assert(master_node != NULL);
+            printf("Automatically selected master %s:%d\n", master_node->ip, 
+                   master_node->port);
+        } 
+    } 
+
+    // Add the new node
+    clusterManagerNode *new_node = clusterManagerNewNode(ip, port);
+    int added = 0;
+    CLUSTER_MANAGER_NODE_CONNECT(new_node);
+    if (new_node->context->err) {
+        clusterManagerLogErr("[ERR] Sorry, can't connect to node %s:%d\n", 
+                             ip, port);
+        success = 0;
+        goto cleanup;
+    }
+    char *err = NULL;
+    if (!(success = clusterManagerNodeIsCluster(new_node, &err))) {
+        clusterManagerPrintNotClusterNodeError(new_node, err);
+        if (err) zfree(err);
+        goto cleanup;
+    }
+    if (!clusterManagerNodeLoadInfo(new_node, 0, &err)) {
+        if (err) {
+            CLUSTER_MANAGER_PRINT_REPLY_ERROR(new_node, err);
+            zfree(err);
+        }
+        success = 0;
+        goto cleanup;
+    }
+    if (!(success = clusterManagerNodeIsEmpty(new_node, &err))) {
+        clusterManagerPrintNotEmptyNodeError(new_node, err);
+        if (err) zfree(err);
+        goto cleanup;
+    }
+    clusterManagerNode *first = listFirst(cluster_manager.nodes)->value;
+    listAddNodeTail(cluster_manager.nodes, new_node);
+    added = 1;
+
+    // Send CLUSTER MEET command to the new node
+    clusterManagerLogInfo(">>> Send CLUSTER MEET to node %s:%d to make it "
+                          "join the cluster.\n", ip, port);
+    reply = CLUSTER_MANAGER_COMMAND(new_node, "CLUSTER MEET %s %d", 
+                                    first->ip, first->port);
+    if (!(success = clusterManagerCheckRedisReply(new_node, reply, NULL)))
+        goto cleanup;
+    
+    /* Additional configuration is needed if the node is added as a slave. */
+    if (master_node) {
+        sleep(1);
+        clusterManagerWaitForClusterJoin();
+        clusterManagerLogInfo(">>> Configure node as replica of %s:%d.\n", 
+                              master_node->ip, master_node->port);
+        freeReplyObject(reply);
+        reply = CLUSTER_MANAGER_COMMAND(new_node, "CLUSTER REPLICATE %s", 
+                                        master_node->name);
+        if (!(success = clusterManagerCheckRedisReply(new_node, reply, NULL)))
+            goto cleanup;
+    } 
+    clusterManagerLogOk("[OK] New node added correctly.\n");
+cleanup:
+    if (!added && new_node) freeClusterManagerNode(new_node);
+    if (reply) freeReplyObject(reply);
+    return success;
+invalid_args:
+    fprintf(stderr, CLUSTER_MANAGER_INVALID_HOST_ARG);
+    return 0;
+}
+
 static int clusterManagerCommandInfo(int argc, char **argv) {
     int port = 0;
     char *ip = NULL;
@@ -4531,8 +4672,7 @@ static int clusterManagerCommandRebalance(int argc, char **argv) {
         nodes_involved++;
         listAddNodeTail(involved, n);
     }
-    weightedNodes = zmalloc(nodes_involved * 
+    weightedNodes = zmalloc(nodes_involved * sizeof(clusterManagerNode *));
-                                                 sizeof(clusterManagerNode *));
     if (weightedNodes == NULL) goto cleanup;
     /* Check cluster, only proceed if it looks sane. */
     clusterManagerCheckCluster(1);