Redis cluster（八）-part 1

一:关于redis cluster

redis cluster的现状

目前redis支持的cluster特性

1):节点自动发现

2):slave->master 选举,集群容错

3):Hot resharding:在线分片

4):进群管理:cluster xxx

5):基于配置(nodes-port.conf)的集群管理

6):ASK 转向/MOVED 转向机制.

redis cluster 架构

1)redis-cluster架构图

架构细节:

(1)所有的redis节点彼此互联(PING-PONG机制),内部使用二进制协议优化传输速度和带宽.

(2)节点的fail是通过集群中超过半数的节点检测失效时才生效.

(3)客户端与redis节点直连,不需要中间proxy层.客户端不需要连接集群所有节点,连接集群中任何一个可用节点即可

(4)redis-cluster把所有的物理节点映射到[0-16383]slot上,cluster 负责维护node<->slot<->value

2) redis-cluster选举:容错

(1)领着选举过程是集群中所有master参与,如果半数以上master节点与master节点通信超过(cluster-node-timeout),认为当前master节点挂掉.

(2):什么时候整个集群不可用(cluster_state:fail),当集群不可用时,所有对集群的操作做都不可用，收到((error) CLUSTERDOWN The cluster is down)错误

    a:如果集群任意master挂掉,且当前master没有slave.集群进入fail状态,也可以理解成进群的slot映射[0-16383]不完成时进入fail状态.

    b:如果进群超过半数以上master挂掉，无论是否有slave集群进入fail状态.

 二:redis cluster的使用

 1:部署和安装redis cluster

～～这里用的是docker：

一、环境

• os：centos7
• redis：3.2.9
• gem-redis：3.2.2（可去下载最新版噢）

二、搭建集群

1、本机下载redis-3.2.9.tar.gz

• redis官网：https://redis.io/download

2、解压安装redis（最少准备 6 个~3m3s）

• 这个可以参考这个 文章地址

3、安装ruby依赖

• yum install ruby rubygems -y

4、本机下载安装gem-redis

• 下载：https://rubygems.org/gems/redis/versions/3.2.2
• 安装：gem install -l /opt/redis-3.2.2.gem

5、配置redis－config

1)redis配置文件结构:

 使用包含(include)把通用配置和特殊配置分离,方便维护

.2)redis通用配置.

#GENERAL  daemonize no  tcp-backlog 511  timeout 0  tcp-keepalive 0  loglevel notice  databases 16  slave-serve-stale-data yes  #slave只读  slave-read-only yes  #not use default  repl-disable-tcp-nodelay yes  slave-priority 100  #打开aof持久化  appendonly no  #每秒一次aof写  appendfsync everysec  #关闭在aof rewrite的时候对新的写操作进行fsync  no-appendfsync-on-rewrite yes  auto-aof-rewrite-min-size 64mb  lua-time-limit 5000  #打开redis集群  cluster-enabled yes  #节点互连超时的阀值  cluster-node-timeout 15000  cluster-migration-barrier 1  slowlog-log-slower-than 10000  slowlog-max-len 128  notify-keyspace-events ""  hash-max-ziplist-entries 512  hash-max-ziplist-value 64  list-max-ziplist-entries 512  list-max-ziplist-value 64  set-max-intset-entries 512  zset-max-ziplist-entries 128  zset-max-ziplist-value 64  activerehashing yes  client-output-buffer-limit normal 0 0 0  client-output-buffer-limit slave 256mb 64mb 60  client-output-buffer-limit pubsub 32mb 8mb 60  hz 10  aof-rewrite-incremental-fsync yes  protected-mode no

3)redis特殊配置.（例如6379的配置）

/sys/fs/cgroup/ 为docker 挂载地址

#包含通用配置  include /sys/fs/cgroup/newconfig/redis_cluster_common.conf#监听tcp端口  port 6379#rdb文件,只用于动态添加slave过程  dbfilename "dump6379.rdb"pidfile "/sys/fs/cgroup/redis_6379.pid"logfile "/sys/fs/cgroup/redis_6379.log"dbfilename "dump6379.rdb"dir "/sys/fs/cgroup"#aof存储文件  appendfilename "appendonly-6379.aof"  #最大可用内存  maxmemory 100m  #内存耗尽时采用的淘汰策略:  # volatile-lru -> remove the key with an expire set using an LRU algorithm  # allkeys-lru -> remove any key accordingly to the LRU algorithm  # volatile-random -> remove a random key with an expire set  # allkeys-random -> remove a random key, any key  # volatile-ttl -> remove the key with the nearest expire time (minor TTL)  # noeviction -> don't expire at all, just return an error on write operations  maxmemory-policy allkeys-lru  #cluster配置文件(启动自动生成)  cluster-config-file nodes-6379.conf  #部署在同一机器的redis实例，把auto-aof-rewrite搓开，#防止瞬间fork所有redis进程做rewrite,占用大量内存 80-100auto-aof-rewrite-percentage 80  

6、启动6个redis实例

 怎么启动就不说了

7、创建集群

./redis-trib.rb  create --replicas 1 127.0.0.1:6379 127.0.0.1:6380 127.0.0.1:6381 127.0.0.1:6382 127.0.0.1:6383 127.0.0.1:6384

记得输入：yes

[root@localhost redis-cluster]# ./redis-trib.rb create --replicas 1 127.0.0.1:6379 127.0.0.1:6380 127.0.0.1:6381 127.0.0.1:6382 127.0.0.1:6383 127.0.0.1:6384  >>> Creating cluster  >>> Performing hash slots allocation on 6 nodes...  Using 3 masters:  127.0.0.1:6379  127.0.0.1:6380  127.0.0.1:6381  Adding replica 127.0.0.1:6382 to 127.0.0.1:6379  Adding replica 127.0.0.1:6383 to 127.0.0.1:6380  Adding replica 127.0.0.1:6384 to 127.0.0.1:6381  M: dfd510594da614469a93a0a70767ec9145aefb1a 127.0.0.1:6379     slots:0-5460 (5461 slots) master  M: e02eac35110bbf44c61ff90175e04d55cca097ff 127.0.0.1:6380     slots:5461-10922 (5462 slots) master  M: 4385809e6f4952ecb122dbfedbee29109d6bb234 127.0.0.1:6381     slots:10923-16383 (5461 slots) master  S: ec02c9ef3acee069e8849f143a492db18d4bb06c 127.0.0.1:6382     replicates dfd510594da614469a93a0a70767ec9145aefb1a  S: 83e5a8bb94fb5aaa892cd2f6216604e03e4a6c75 127.0.0.1:6383     replicates e02eac35110bbf44c61ff90175e04d55cca097ff  S: 10c097c429ca24f8720986c6b66f0688bfb901ee 127.0.0.1:6384     replicates 4385809e6f4952ecb122dbfedbee29109d6bb234  Can I set the above configuration? (type 'yes' to accept): yes  >>> Nodes configuration updated  >>> Assign a different config epoch to each node  >>> Sending CLUSTER MEET messages to join the cluster  Waiting for the cluster to join......  >>> Performing Cluster Check (using node 127.0.0.1:6379)  M: dfd510594da614469a93a0a70767ec9145aefb1a 127.0.0.1:6379     slots:0-5460 (5461 slots) master  M: e02eac35110bbf44c61ff90175e04d55cca097ff 127.0.0.1:6380     slots:5461-10922 (5462 slots) master  M: 4385809e6f4952ecb122dbfedbee29109d6bb234 127.0.0.1:6381     slots:10923-16383 (5461 slots) master  M: ec02c9ef3acee069e8849f143a492db18d4bb06c 127.0.0.1:6382     slots: (0 slots) master     replicates dfd510594da614469a93a0a70767ec9145aefb1a  M: 83e5a8bb94fb5aaa892cd2f6216604e03e4a6c75 127.0.0.1:6383     slots: (0 slots) master     replicates e02eac35110bbf44c61ff90175e04d55cca097ff  M: 10c097c429ca24f8720986c6b66f0688bfb901ee 127.0.0.1:6384     slots: (0 slots) master     replicates 4385809e6f4952ecb122dbfedbee29109d6bb234  [OK] All nodes agree about slots configuration.  >>> Check for open slots...  >>> Check slots coverage...  [OK] All 16384 slots covered.  

8、java简单测试代码

import java.io.IOException;import java.util.HashSet;import java.util.Set;import redis.clients.jedis.HostAndPort;import redis.clients.jedis.JedisCluster;import redis.clients.jedis.JedisPoolConfig;public class RedisClusterTest { public static void main(String[] args) throws IOException { JedisCluster jedisCluster=null; try{ JedisPoolConfig config = new JedisPoolConfig();      config.setMaxTotal(1000);    config.setMaxIdle(100);       config.setTestOnBorrow(true);          Set<HostAndPort> nodes = new HashSet<HostAndPort>();      String host="192.168.1.107";    HostAndPort hostAndPort = new HostAndPort(host,6379);      HostAndPort hostAndPort1 = new HostAndPort(host,6380);      HostAndPort hostAndPort2 = new HostAndPort(host,6381);      HostAndPort hostAndPort3 = new HostAndPort(host,6382);      HostAndPort hostAndPort4 = new HostAndPort(host,6383);      HostAndPort hostAndPort5 = new HostAndPort(host,6384);                   nodes.add(hostAndPort);      nodes.add(hostAndPort1);      nodes.add(hostAndPort2);      nodes.add(hostAndPort3);      nodes.add(hostAndPort4);      nodes.add(hostAndPort5);         jedisCluster=new JedisCluster(nodes,5000,config);   jedisCluster.set("kkk", "1");   String kkk = jedisCluster.get("kkk");     System.out.println(kkk); }finally {if(null!=jedisCluster)   jedisCluster.close();}  }   }