Redis Cluster 的实现 - 初始化(1)
void clusterInit(void) {int saveconf = 0;
/* 对 redisServer 结构中的 clusterState 进行初始化 */
server.cluster = zmalloc(sizeof(clusterState));
server.cluster->myself = NULL;
server.cluster->currentEpoch = 0;
// 初始为 FAIL 状态
server.cluster->state = REDIS_CLUSTER_FAIL;
// master 节点数
server.cluster->size = 1;
server.cluster->todo_before_sleep = 0;
server.cluster->nodes = dictCreate(&clusterNodesDictType,NULL);
server.cluster->nodes_black_list =
dictCreate(&clusterNodesBlackListDictType,NULL);
server.cluster->failover_auth_time = 0;
server.cluster->failover_auth_count = 0;
server.cluster->failover_auth_rank = 0;
server.cluster->failover_auth_epoch = 0;
server.cluster->lastVoteEpoch = 0;
server.cluster->stats_bus_messages_sent = 0;
server.cluster->stats_bus_messages_received = 0;
memset(server.cluster->slots,0, sizeof(server.cluster->slots));
clusterCloseAllSlots();
/* Lock the cluster config file to make sure every node uses
* its own nodes.conf. */
if (clusterLockConfig(server.cluster_configfile) == REDIS_ERR)
exit(1);
/* Load or create a new nodes configuration. */
// 加载或创建一个新的 节点配置 文件
// 如果加载失败，则通过 createClusterNode 来创建一个 flags = MYSELF|MASTER 的新节点
if (clusterLoadConfig(server.cluster_configfile) == REDIS_ERR) {
/* No configuration found. We will just use the random name provided
* by the createClusterNode() function. */
myself = server.cluster->myself =
createClusterNode(NULL,REDIS_NODE_MYSELF|REDIS_NODE_MASTER);
redisLog(REDIS_NOTICE,"No cluster configuration found, I'm %.40s",
myself->name);
// 将此节点加入 cluster 的 nodes hash table 中
// 该 nodes 维护的是一张 nodeName -> node 的 hash 表
clusterAddNode(myself);
saveconf = 1;
}
// 具体的配置文件名由参数 cluster-config-file 来指定
if (saveconf) clusterSaveConfigOrDie(1);
/* We need a listening TCP port for our cluster messaging needs. */
server.cfd_count = 0;
/* Port sanity check II
* The other handshake port check is triggered too late to stop
* us from trying to use a too-high cluster port number. */
// 这里是做端口校验，要求 redis 面向客户端的监听端口必须小于 55535，这样才能避免出现
// cluster 通道的监听端口 > 65535 的情形
if (server.port > (65535-REDIS_CLUSTER_PORT_INCR)) {
redisLog(REDIS_WARNING, "Redis port number too high. "
"Cluster communication port is 10,000 port "
"numbers higher than your Redis port. "
"Your Redis port number must be "
"lower than 55535.");
exit(1);
}
// 打开 cluster 通道的 非阻塞监听端口
if (listenToPort(server.port+REDIS_CLUSTER_PORT_INCR,
server.cfd,&server.cfd_count) == REDIS_ERR)
{
exit(1);
} else {
int j;
// 在一个或多个非阻塞监听套接字上创建 ACCEPT 事件处理器
// 可以根据系统平台选择合适的 事件模型(如：Linux 上的 epoll，具体查看 aeApiAddEvent 源码)
// 这里指定了 clusterAcceptHandler 函数作为 ACCEPT 事件处理器
for (j = 0; j < server.cfd_count; j++) {
if (aeCreateFileEvent(server.el, server.cfd, AE_READABLE,
clusterAcceptHandler, NULL) == AE_ERR)
redisPanic("Unrecoverable error creating Redis Cluster "
"file event.");
}
}
/* The slots -> keys map is a sorted set. Init it. */
server.cluster->slots_to_keys = zslCreate();
/* Set myself->port to my listening port, we'll just need to discover
* the IP address via MEET messages. */
myself->port = server.port;
resetManualFailover();
}
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