redis集群主从复制、哨兵模式、cluster模式

短命女 2022-12-30 13:34 259阅读 0赞

# redis集群的三种模式 #

转载于： https://blog.csdn.net/miss1181248983/article/details/90056960

* 主从模式    master挂掉后，就不能继续为外部提供服务
    
    * Sentinel模式  哨兵模式
    
    * Cluster模式

## sentinel 哨兵模式的特点： ##

* sentinel模式是建立在主从模式的基础上，如果只有一个Redis节点，sentinel就没有任何意义
    
    * 当master挂了以后，sentinel会在slave中选择一个做为master，并修改它们的配置文件，其他slave的配置文件也会被修改，比如slaveof属性会指向新的master
    
    * 当master重新启动后，它将不再是master而是做为slave接收新的master的同步数据
    
    * sentinel因为也是一个进程有挂掉的可能，所以sentinel也会启动多个形成一个sentinel集群
    
    * 多sentinel配置的时候，sentinel之间也会自动监控
    
    * 当主从模式配置密码时，sentinel也会同步将配置信息修改到配置文件中，不需要担心
    
    * 一个sentinel或sentinel集群可以管理多个主从Redis，多个sentinel也可以监控同一个redis
    
    * sentinel最好不要和Redis部署在同一台机器，不然Redis的服务器挂了以后，sentinel也挂了

工作机制：

* 每个sentinel以每秒钟一次的频率向它所知的master，slave以及其他sentinel实例发送一个 PING 命令 
    
    * 如果一个实例距离最后一次有效回复 PING 命令的时间超过 down-after-milliseconds 选项所指定的值， 则这个实例会被sentinel标记为主观下线。 
    
    * 如果一个master被标记为主观下线，则正在监视这个master的所有sentinel要以每秒一次的频率确认master的确进入了主观下线状态
    
    * 当有足够数量的sentinel（大于等于配置文件指定的值）在指定的时间范围内确认master的确进入了主观下线状态， 则master会被标记为客观下线 
    
    * 在一般情况下， 每个sentinel会以每 10 秒一次的频率向它已知的所有master，slave发送 INFO 命令 
    
    * 当master被sentinel标记为客观下线时，sentinel向下线的master的所有slave发送 INFO 命令的频率会从 10 秒一次改为 1 秒一次 
    
    * 若没有足够数量的sentinel同意master已经下线，master的客观下线状态就会被移除；
      若master重新向sentinel的 PING 命令返回有效回复，master的主观下线状态就会被移除

## **cluster模式** ##

sentinel模式基本可以满足一般生产的需求，具备高可用性。但是当数据量过大到一台服务器存放不下的情况时，主从模式或sentinel模式就不能满足需求了，这个时候需要对存储的数据进行分片，将数据存储到多个Redis实例中。cluster模式的出现就是为了解决单机Redis容量有限的问题，将Redis的数据根据一定的规则分配到多台机器。

cluster可以说是sentinel和主从模式的结合体，通过cluster可以实现主从和master重选功能，所以如果配置两个副本三个分片的话，就需要六个Redis实例。因为Redis的数据是根据一定规则分配到cluster的不同机器的，当数据量过大时，可以新增机器进行扩容。

使用集群，只需要将redis配置文件中的`cluster-enable`配置打开即可。每个集群中至少需要三个主数据库才能正常运行，新增节点非常方便。

* 多个redis节点网络互联，数据共享
    
    * 所有的节点都是一主一从（也可以是一主多从），其中从不提供服务，仅作为备用
    
    * 不支持同时处理多个key（如MSET/MGET），因为redis需要把key均匀分布在各个节点上，
      并发量很高的情况下同时创建key-value会降低性能并导致不可预测的行为
      
    * 支持在线增加、删除节点
    
    * 客户端可以连接任何一个主节点进行读写

三台机器，分别开启两个redis服务（端口）

192.168.30.128 端口：7001,7002

192.168.30.129 端口：7003,7004

192.168.30.130 端口：7005,7006

**配置文件：**

192.168.30.128

# mkdir /usr/local/redis/cluster
    
    # cp /usr/local/redis/redis.conf /usr/local/redis/cluster/redis_7001.conf
    
    # cp /usr/local/redis/redis.conf /usr/local/redis/cluster/redis_7002.conf
    
    # chown -R redis:redis /usr/local/redis
    
    # mkdir -p /data/redis/cluster/{redis_7001,redis_7002} && chown -R redis:redis /data/redis

192.168.30.128 7001 配置文件

# vim /usr/local/redis/cluster/redis_7001.conf
    
    bind 192.168.30.128
    port 7001
    daemonize yes
    pidfile "/var/run/redis_7001.pid"
    logfile "/usr/local/redis/cluster/redis_7001.log"
    dir "/data/redis/cluster/redis_7001"
    #replicaof 192.168.30.129 6379
    masterauth 123456
    requirepass 123456
    appendonly yes
    cluster-enabled yes
    cluster-config-file nodes_7001.conf
    cluster-node-timeout 15000

192.168.30.128 7002 配置文件

# vim /usr/local/redis/cluster/redis_7002.conf
    
    bind 192.168.30.128
    port 7002
    daemonize yes
    pidfile "/var/run/redis_7002.pid"
    logfile "/usr/local/redis/cluster/redis_7002.log"
    dir "/data/redis/cluster/redis_7002"
    #replicaof 192.168.30.129 6379
    masterauth "123456"
    requirepass "123456"
    appendonly yes
    cluster-enabled yes
    cluster-config-file nodes_7002.conf
    cluster-node-timeout 15000

启动redis服务：

# redis-server /usr/local/redis/cluster/redis_7001.conf
    
    # tail -f /usr/local/redis/cluster/redis_7001.log
    
    # redis-server /usr/local/redis/cluster/redis_7002.conf
    
    # tail -f /usr/local/redis/cluster/redis_7002.log

redis5.0.4，所以不需要安装ruby，直接创建集群即可

# redis-cli -a 123456 --cluster create 192.168.30.128:7001 192.168.30.128:7002 192.168.30.129:7003 192.168.30.129:7004 192.168.30.130:7005 192.168.30.130:7006 --cluster-replicas 1
    
    Warning: Using a password with '-a' or '-u' option on the command line interface may not be safe.
    >>> Performing hash slots allocation on 6 nodes...
    Master[0] -> Slots 0 - 5460
    Master[1] -> Slots 5461 - 10922
    Master[2] -> Slots 10923 - 16383
    Adding replica 192.168.30.129:7004 【slave】 to 192.168.30.128:7001 【master】
    Adding replica 192.168.30.130:7006 【slave】 to 192.168.30.129:7003 【master】
    Adding replica 192.168.30.128:7002 【slave】 to 192.168.30.130:7005 【master】
    M: 80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001
       slots:[0-5460] (5461 slots) master
    S: b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002
       replicates 6788453ee9a8d7f72b1d45a9093838efd0e501f1
    M: 4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003
       slots:[5461-10922] (5462 slots) master
    S: b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004
       replicates 80c80a3f3e33872c047a8328ad579b9bea001ad8
    M: 6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005
       slots:[10923-16383] (5461 slots) master
    S: 277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006
       replicates 4d74ec66e898bf09006dac86d4928f9fad81f373
    Can I set the above configuration? (type 'yes' to accept): yes                  #输入yes，接受上面配置
    >>> Nodes configuration updated
    >>> Assign a different config epoch to each node
    >>> Sending CLUSTER MEET messages to join the cluster

自动生成的nodes.conf文件

# ls /data/redis/cluster/redis_7001/
    appendonly.aof  dump.rdb  nodes-7001.conf
    
    # vim /data/redis/cluster/redis_7001/nodes-7001.conf 
    
    6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557454406312 5 connected 10923-16383
    277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557454407000 6 connected
    b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557454408371 5 connected
    80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557454406000 1 connected 0-5460
    b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557454407366 4 connected
    4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557454407000 3 connected 5461-10922
    vars currentEpoch 6 lastVoteEpoch 0

登录集群操作：

# redis-cli -c -h 192.168.30.128 -p 7001 -a 123456                  # -c，使用集群方式登录

查看集群信息：

192.168.30.128:7001> CLUSTER INFO                   #集群状态
    
    cluster_state:ok
    cluster_slots_assigned:16384
    cluster_slots_ok:16384
    cluster_slots_pfail:0
    cluster_slots_fail:0
    cluster_known_nodes:6
    cluster_size:3
    cluster_current_epoch:6
    cluster_my_epoch:1
    cluster_stats_messages_ping_sent:580
    cluster_stats_messages_pong_sent:551
    cluster_stats_messages_sent:1131
    cluster_stats_messages_ping_received:546
    cluster_stats_messages_pong_received:580
    cluster_stats_messages_meet_received:5
    cluster_stats_messages_received:1131

列出节点信息： 这里与 nodes.conf 中的内容一致

192.168.30.128:7001> CLUSTER NODES                  #列出节点信息
    
    6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557455176000 5 connected 10923-16383
    277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557455174000 6 connected
    b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557455175000 5 connected
    80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 myself,master - 0 1557455175000 1 connected 0-5460
    b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557455174989 4 connected
    4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557455175995 3 connected 5461-10922

192.168.30.129上增加一节点：

# cp /usr/local/redis/cluster/redis_7003.conf /usr/local/redis/cluster/redis_7007.conf
    
    # vim /usr/local/redis/cluster/redis_7007.conf
    
    bind 192.168.30.129
    port 7007
    daemonize yes
    pidfile "/var/run/redis_7007.pid"
    logfile "/usr/local/redis/cluster/redis_7007.log"
    dir "/data/redis/cluster/redis_7007"
    #replicaof 192.168.30.129 6379
    masterauth "123456"
    requirepass "123456"
    appendonly yes
    cluster-enabled yes
    cluster-config-file nodes_7007.conf
    cluster-node-timeout 15000
    
    # mkdir /data/redis/cluster/redis_7007
    
    # chown -R redis:redis /usr/local/redis && chown -R redis:redis /data/redis
    
    # redis-server /usr/local/redis/cluster/redis_7007.conf

192.168.30.130上增加一节点：

# cp /usr/local/redis/cluster/redis_7005.conf /usr/local/redis/cluster/redis_7008.conf
    
    # vim /usr/local/redis/cluster/redis_7007.conf
    
    bind 192.168.30.130
    port 7008
    daemonize yes
    pidfile "/var/run/redis_7008.pid"
    logfile "/usr/local/redis/cluster/redis_7008.log"
    dir "/data/redis/cluster/redis_7008"
    #replicaof 192.168.30.130 6379
    masterauth "123456"
    requirepass "123456"
    appendonly yes
    cluster-enabled yes
    cluster-config-file nodes_7008.conf
    cluster-node-timeout 15000
    
    # mkdir /data/redis/cluster/redis_7008
    
    # chown -R redis:redis /usr/local/redis && chown -R redis:redis /data/redis
    
    # redis-server /usr/local/redis/cluster/redis_7008.conf

集群中增加节点：

192.168.30.129:7003> CLUSTER MEET 192.168.30.129 7007
    OK
    
    192.168.30.129:7003> CLUSTER NODES
    
    4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 myself,master - 0 1557457361000 3 connected 5461-10922
    80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557457364746 1 connected 0-5460
    277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557457362000 6 connected
    b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557457363000 4 connected
    b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557457362000 5 connected
    e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557457362729 0 connected
    6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557457363739 5 connected 10923-16383

192.168.30.129:7003> CLUSTER MEET 192.168.30.130 7008
    OK
    
    192.168.30.129:7003> CLUSTER NODES
    
    4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 myself,master - 0 1557457489000 3 connected 5461-10922
    80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557457489000 1 connected 0-5460
    277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557457489000 6 connected
    b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557457488000 4 connected
    b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557457489472 5 connected
    1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 master - 0 1557457489259 0 connected
    e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557457489000 0 connected
    6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557457490475 5 connected 10923-16383

可以看到，新增的节点都是以master身份加入集群的

*  更换节点身份：

将新增的192.168.30.130:7008节点身份改为192.168.30.129:7007的slave

# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456 cluster replicate e51ab166bc0f33026887bcf8eba0dff3d5b0bf14

`cluster replicate`后面跟node\_id，更改对应节点身份。也可以登入集群更改

# redis-cli -c -h 192.168.30.130 -p 7008 -a 123456
    
    192.168.30.130:7008> CLUSTER REPLICATE e51ab166bc0f33026887bcf8eba0dff3d5b0bf14
    OK
    
    192.168.30.130:7008> CLUSTER NODES
    
    277daeb8660d5273b7c3e05c263f861ed5f17b92 192.168.30.130:7006@17006 slave 4d74ec66e898bf09006dac86d4928f9fad81f373 0 1557458316881 3 connected
    80c80a3f3e33872c047a8328ad579b9bea001ad8 192.168.30.128:7001@17001 master - 0 1557458314864 1 connected 0-5460
    4d74ec66e898bf09006dac86d4928f9fad81f373 192.168.30.129:7003@17003 master - 0 1557458316000 3 connected 5461-10922
    6788453ee9a8d7f72b1d45a9093838efd0e501f1 192.168.30.130:7005@17005 master - 0 1557458315872 5 connected 10923-16383
    b4d3eb411a7355d4767c6c23b4df69fa183ef8bc 192.168.30.128:7002@17002 slave 6788453ee9a8d7f72b1d45a9093838efd0e501f1 0 1557458317890 5 connected
    1a1c7f02fce87530bd5abdfc98df1cffce4f1767 192.168.30.130:7008@17008 myself,slave e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 0 1557458315000 7 connected
    b6331cbc986794237c83ed2d5c30777c1551546e 192.168.30.129:7004@17004 slave 80c80a3f3e33872c047a8328ad579b9bea001ad8 0 1557458315000 1 connected
    e51ab166bc0f33026887bcf8eba0dff3d5b0bf14 192.168.30.129:7007@17007 master - 0 1557458314000 0 connected