一起学docker(五)| 搭建MySQL主从复制,Redis集群(三主三从)

2024-01-03 13:50:30

安装MySQL主从复制

一主一从

mysql-master
  1. 新建主服务器容器实例

    docker run -id \
    -p 3307:3306 \
    --name mysql-master \
    -v /mydata/mysql-master/log:/var/log/mysql \
    -v /mydata/mysql-master/data:/var/lib/mysql \
    -v /mydata/mysql-master/conf:/etc/mysql \
    -e MYSQL_ROOT_PASSWORD=admin  \
    mysql:5.7
    
  2. 进入**/mydata/mysql-master/conf**目录下新建my.cnfvim my.cnf

    [mysqld]
    ## 设置server_id,同一局域网中需要唯一
    server_id=101 
    
    ## 指定不需要同步的数据库名称
    binlog-ignore-db=mysql  
    
    ## 开启二进制日志功能
    log-bin=mall-mysql-bin  
    
    ## 设置二进制日志使用内存大小(事务)
    binlog_cache_size=1M  
    
    ## 设置使用的二进制日志格式(mixed,statement,row)
    binlog_format=mixed  
    
    ## 二进制日志过期清理时间。默认值为0,表示不自动清理。
    expire_logs_days=7  
    
    ## 跳过主从复制中遇到的所有错误或指定类型的错误,避免slave端复制中断。
    ## 如:1062错误是指一些主键重复,1032错误是因为主从数据库数据不一致
    slave_skip_errors=1062
    
  3. 重启mysql-master实例docker restart mysql-master

  4. 进入容器测试

  5. 在master实例创建数据同步用户

    create user 'slave'@'%' identified by '123456';
    
    grant replication slave,replication client on *.* to 'slave'@'%';
    
    show grants for 'slave'@'%';
    
mysql-slave
  1. 新建slave实例

    docker run -id \
    -p 3308:3306 \
    --name mysql-slave \
    -v /mydata/mysql-slave/log:/var/log/mysql \
    -v /mydata/mysql-slave/data:/var/lib/mysql \
    -v /mydata/mysql-slave/conf:/etc/mysql \
    -e MYSQL_ROOT_PASSWORD=admin  \
    mysql:5.7
    
  2. 进入**/mydata/mysql-master/conf**目录下新建my.cnfvim my.cnf

    [mysqld]
    ## 设置server_id,同一局域网中需要唯一
    server_id=102
    
    ## 指定不需要同步的数据库名称
    binlog-ignore-db=mysql  
    
    ## 开启二进制日志功能,以备Slave作为其它数据库实例的Master时使用
    log-bin=mall-mysql-slave1-bin  
    
    ## 设置二进制日志使用内存大小(事务)
    binlog_cache_size=1M  
    
    ## 设置使用的二进制日志格式(mixed,statement,row)
    binlog_format=mixed  
    
    ## 二进制日志过期清理时间。默认值为0,表示不自动清理。
    expire_logs_days=7  
    
    ## 跳过主从复制中遇到的所有错误或指定类型的错误,避免slave端复制中断。
    ## 如:1062错误是指一些主键重复,1032错误是因为主从数据库数据不一致
    slave_skip_errors=1062  
    
    ## relay_log配置中继日志
    relay_log=mall-mysql-relay-bin  
    
    ## log_slave_updates表示slave将复制事件写进自己的二进制日志
    log_slave_updates=1  
    
    ## slave设置为只读(具有super权限的用户除外)
    read_only=1
    
  3. 重启slave实例docker restart mysql-slave

  4. 在主数据库中查看主从同步状态show master status;

    mysql> show master status;
    +-----------------------+----------+--------------+------------------+-------------------+
    | File                  | Position | Binlog_Do_DB | Binlog_Ignore_DB | Executed_Gtid_Set |
    +-----------------------+----------+--------------+------------------+-------------------+
    | mall-mysql-bin.000001 |      154 |              | mysql            |                   |
    +-----------------------+----------+--------------+------------------+-------------------+
    1 row in set (0.00 sec)
    
  5. 进入从数据库

    docker exec -it mysql-slave /bin/bash
    
    mysql -uroot -p
    
  6. 在从数据库配置主从复制

    • 命令change master to master_host='宿主机ip', master_user='slave', master_password='123456', master_port=3307, master_log_file='mall-mysql-bin.000001', master_log_pos=617, master_connect_retry=30;

      mysql> change master to master_host='121.4.126.115', master_user='slave', master_password='123456', master_port=3307, master_log_file='mall-mysql-bin.000001', master_log_pos=154, master_connect_retry=30;
      Query OK, 0 rows affected, 2 warnings (0.05 sec)
      
      mysql> 
      
    • 参数说明

      master_host:主数据库的IP地址;
      
      master_port:主数据库的运行端口;
      
      master_user:在主数据库创建的用于同步数据的用户账号;
      
      master_password:在主数据库创建的用于同步数据的用户密码;
      
      master_log_file:指定从数据库要复制数据的日志文件,通过查看主数据的状态,获取File参数;
      
      master_log_pos:指定从数据库从哪个位置开始复制数据,通过查看主数据的状态,获取Position参数;
      
      master_connect_retry:连接失败重试的时间间隔,单位为秒。
      
  7. 在从数据库查看主从同步状态show slave status \G;

    mysql> show slave status \G;
    *************************** 1. row ***************************
                   Slave_IO_State: 
                      Master_Host: 121.4.126.115
                      Master_User: slave
                      Master_Port: 3307
                    Connect_Retry: 30
                  Master_Log_File: mall-mysql-bin.000001
              Read_Master_Log_Pos: 154
                   Relay_Log_File: mall-mysql-relay-bin.000001
                    Relay_Log_Pos: 4
            Relay_Master_Log_File: mall-mysql-bin.000001
                 Slave_IO_Running: No
                Slave_SQL_Running: No
                                ...
                                ...
                                
    # Slave_IO_Running: No
    # Slave_SQL_Running: No
    # 表示没开始同步
    
  8. 在从数据库开启主从同步start slave;

    mysql> start slave;
    Query OK, 0 rows affected (0.01 sec)
    
  9. 再次在从数据库查看主从同步状态

    mysql> show slave status \G;
    *************************** 1. row ***************************
                   Slave_IO_State: Waiting for master to send event
                      Master_Host: 121.4.126.115
                      Master_User: slave
                      Master_Port: 3307
                    Connect_Retry: 30
                  Master_Log_File: mall-mysql-bin.000001
              Read_Master_Log_Pos: 154
                   Relay_Log_File: mall-mysql-relay-bin.000002
                    Relay_Log_Pos: 325
            Relay_Master_Log_File: mall-mysql-bin.000001
                 Slave_IO_Running: Yes
                Slave_SQL_Running: Yes
    
  10. 主从复制测试

    • 主库新建库-新建表-插入数据
    • 从库查看数据

安装Redis集群

分布式存储原理
哈希取余分区

在这里插入图片描述

2亿条记录就是2亿个k,v,我们单机不行必须要分布式多机,假设有3台机器构成一个集群,用户每次读写操作都是根据公式:
hash(key) % N个机器台数,计算出哈希值,用来决定数据映射到哪一个节点上。

  • 优点:
    简单粗暴,直接有效,只需要预估好数据规划好节点,例如3台、8台、10台,就能保证一段时间的数据支撑。使用Hash算法让固定的一部分请求落到同一台服务器上,这样每台服务器固定处理一部分请求(并维护这些请求的信息),起到负载均衡+分而治之的作用。
  • 缺点:
    原来规划好的节点,进行扩容或者缩容就比较麻烦了额,不管扩缩,每次数据变动导致节点有变动,映射关系需要重新进行计算,在服务器个数固定不变时没有问题,如果需要弹性扩容或故障停机的情况下,原来的取模公式就会发生变化:Hash(key)/3会变成Hash(key) /?。此时地址经过取余运算的结果将发生很大变化,根据公式获取的服务器也会变得不可控。
    某个redis机器宕机了,由于台数数量变化,会导致hash取余全部数据重新洗牌。
一致性哈希算法分区

一致性哈希算法在1997年由麻省理工学院中提出的,设计目标是为了解决分布式缓存数据变动和映射问题,某个机器宕机了,分母数量改变了,自然取余数不OK了。

作用:

提出一致性Hash解决方案。目的是当服务器个数发生变动时,尽量减少影响客户端到服务器的映射关系

步骤:

  1. 算法构建一致性哈希环

    • 一致性哈希算法必然有个hash函数并按照算法产生hash值,这个算法的所有可能哈希值会构成一个全量集,这个集合可以成为一个hash空间[0,2^32-1],这个是一个线性空间,但是在算法中,我们通过适当的逻辑控制将它首尾相连(0 = 2^32),这样让它逻辑上形成了一个环形空间

    • 它也是按照使用取模的方法,前面笔记介绍的节点取模法是对节点(服务器)的数量进行取模。而一致性Hash算法是对232取模**,简单来说,一致性Hash算法将整个哈希值空间组织成一个虚拟的圆环,如假设某哈希函数H的值空间为0-232-1(即哈希值是一个32位无符号整形),整个哈希环如下图:整个空间按顺时针**方向组织,圆环的正上方的点代表0,0点右侧的第一个点代表1,以此类推,2、3、4、……直到232-1,也就是说0点左侧的第一个点代表232-1, 0和232-1在零点中方向重合,我们把这个由232个点组成的圆环称为Hash环。

    在这里插入图片描述

  2. 服务器IP节点映射

    • 将集群中各个IP节点映射到环上的某一个位置。

    • 将各个服务器使用Hash进行一个哈希,具体可以选择服务器的IP或主机名作为关键字进行哈希,这样每台机器就能确定其在哈希环上的位置。假如4个节点NodeA、B、C、D,经过IP地址的哈希函数计算(hash(ip)),使用IP地址哈希后在环空间的位置如下:

      在这里插入图片描述

  3. key落到服务器的落键规则

    • 当我们需要存储一个kv键值对时,首先计算key的hash值,hash(key),将这个key使用相同的函数Hash计算出哈希值并确定此数据在环上的位置,从此位置沿环顺时针“行走”,第一台遇到的服务器就是其应该定位到的服务器,并将该键值对存储在该节点上

    • 如我们有Object A、Object B、Object C、Object D四个数据对象,经过哈希计算后,在环空间上的位置如下:根据一致性Hash算法,数据A会被定为到Node A上,B被定为到Node B上,C被定为到Node C上,D被定为到Node D上。

      在这里插入图片描述

优点:

  • 容错性

    • 假设Node C宕机,可以看到此时对象A、B、D不会受到影响,只有C对象被重定位到Node D。一般的,在一致性Hash算法中,如果一台服务器不可用,则受影响的数据仅仅是此服务器到其环空间中前一台服务器(即沿着逆时针方向行走遇到的第一台服务器)之间数据,其它不会受到影响。简单说,就是C挂了,受到影响的只是B、C之间的数据,并且这些数据会转移到D进行存储。

      在这里插入图片描述

  • 扩展性

    • 数据量增加了,需要增加一台节点NodeX,X的位置在A和B之间,那收到影响的也就是A到X之间的数据,重新把A到X的数据录入到X上即可,不会导致hash取余全部数据重新洗牌。

      在这里插入图片描述

缺点:

数据倾斜问题

  • 一致性Hash算法在服务节点太少时,容易因为节点分布不均匀而造成数据倾斜(被缓存的对象大部分集中缓存在某一台服务器上)问题;

  • 例如系统中只有两台服务器:

    在这里插入图片描述

总结:

  • 目的:为了在节点数目发生改变时尽可能少的迁移数据

  • 将所有的存储节点排列在收尾相接的Hash环上,每个key在计算Hash后会顺时针找到临近的存储节点存放。
    而当有节点加入或退出时仅影响该节点在Hash环上顺时针相邻的后续节点

  • 优点

    • 加入和删除节点只影响哈希环中顺时针方向的相邻的节点,对其他节点无影响。
  • 缺点

    • 数据的分布和节点的位置有关,因为这些节点不是均匀的分布在哈希环上的,所以数据在进行存储时达不到均匀分布的效果。
哈希槽分区

为什么出现?

解决一致性哈希算法的数据倾斜问题

哈希槽实质就是一个数组,数组[0,2^14 -1]形成hash slot空间。

能干什么?

解决均匀分配的问题,在数据和节点之间又加入了一层,把这层称为哈希槽(slot),用于管理数据和节点之间的关系,现在就相当于节点上放的是槽,槽里放的是数据。

在这里插入图片描述

  • 槽解决的是粒度问题,相当于把粒度变大了,这样便于数据移动。
  • 哈希解决的是映射问题,使用key的哈希值来计算所在的槽,便于数据分配。

多少个哈希槽?

一个集群只能有16384个槽,编号0-16383(0-2^14-1)。这些槽会分配给集群中的所有主节点,分配策略没有要求。可以指定哪些编号的槽分配给哪个主节点。集群会记录节点和槽的对应关系。解决了节点和槽的关系后,接下来就需要对key求哈希值,然后对16384取余,余数是几key就落入对应的槽里。slot = CRC16(key) % 16384。以槽为单位移动数据,因为槽的数目是固定的,处理起来比较容易,这样数据移动问题就解决了。

哈希槽计算?

Redis 集群中内置了 16384 个哈希槽,redis 会根据节点数量大致均等的将哈希槽映射到不同的节点。当需要在 Redis 集群中放置一个 key-value时,**redis 先对 key 使用 crc16 算法算出一个结果,然后把结果对 16384 求余数,这样每个 key 都会对应一个编号在 0-16383 之间的哈希槽,也就是映射到某个节点上。**如下代码,key之A 、B在Node2, key之C落在Node3上:

在这里插入图片描述

三主三从
  1. 新建6个Redis实例

    • 命令

      docker run -d --name redis-node-1 --net host --privileged=true -v /data/redis/share/redis-node-1:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6381
       
      docker run -d --name redis-node-2 --net host --privileged=true -v /data/redis/share/redis-node-2:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6382
       
      docker run -d --name redis-node-3 --net host --privileged=true -v /data/redis/share/redis-node-3:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6383
       
      docker run -d --name redis-node-4 --net host --privileged=true -v /data/redis/share/redis-node-4:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6384
       
      docker run -d --name redis-node-5 --net host --privileged=true -v /data/redis/share/redis-node-5:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6385
       
      docker run -d --name redis-node-6 --net host --privileged=true -v /data/redis/share/redis-node-6:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6386
      
    • 解释

      • docker run 创建并运行docker容器实例
      • –name redis-node-6 容器名字
      • –net host 使用宿主机的IP和端口,默认
      • –privileged=true 获取宿主机root用户权限
      • -v /data/redis/share/redis-node-6:/data 容器卷,宿主机地址:docker内部地址
      • redis:6.0.8 redis镜像和版本号
      • –cluster-enabled yes 开启redis集群
      • –appendonly yes 开启持久化
      • –port 6386 redis端口号
  2. 进入redis-node-1实例为6台机器构建集群关系

    • 进入实例docker exec -it redis-node-1 /bin/bash

    • 构建主从关系(–cluster-replicas 1 表示为每个master创建一个slave节点)

      redis-cli --cluster create 121.4.126.115:6381 121.4.126.115:6382 121.4.126.115:6383 121.4.126.115:6384 121.4.126.115:6385 121.4.126.115:6386 --cluster-replicas 1
      
    • 结果

      >>> Performing Cluster Check (using node 121.4.126.115:6381)
      M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
         slots:[0-5460] (5461 slots) master
         1 additional replica(s)
      S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
         slots: (0 slots) slave
         replicates 94187dcb0b28376f33e1169845e94af079f7241c
      S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
         slots: (0 slots) slave
         replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
      M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
         slots:[10923-16383] (5461 slots) master
         1 additional replica(s)
      S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
         slots: (0 slots) slave
         replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
      M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
         slots:[5461-10922] (5462 slots) master
         1 additional replica(s)
      [OK] All nodes agree about slots configuration.
      >>> Check for open slots...
      >>> Check slots coverage...
      [OK] All 16384 slots covered.
      root@VM-4-9-centos:/data# 
      
  3. 以6381实例作切入点,查看集群状态redis-cli -p 6381

    • cluster info

      127.0.0.1:6381> cluster info
      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:354
      cluster_stats_messages_pong_sent:341
      cluster_stats_messages_sent:695
      cluster_stats_messages_ping_received:336
      cluster_stats_messages_pong_received:354
      cluster_stats_messages_meet_received:5
      cluster_stats_messages_received:695
      127.0.0.1:6381> 
      
    • cluster nodes

      127.0.0.1:6381> cluster nodes
      2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384@16384 slave 94187dcb0b28376f33e1169845e94af079f7241c 0 1691574060189 3 connected
      1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385@16385 slave 4841f1647bab764ae048e50ec4283b01d8010b3b 0 1691574061191 1 connected
      94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383@16383 master - 0 1691574058186 3 connected 10923-16383
      2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386@16386 slave 19e471a30df72ac8d83729814aaf2286e2c5315f 0 1691574058000 2 connected
      19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382@16382 master - 0 1691574060000 2 connected 5461-10922
      4841f1647bab764ae048e50ec4283b01d8010b3b 10.0.4.9:6381@16381 myself,master - 0 1691574055000 1 connected 0-5460
      127.0.0.1:6381> 
      

注意:

还可以使用redis-cli --cluster check 121.4.126.115:6381查看集群状态

root@VM-4-9-centos:/data# redis-cli --cluster check 121.4.126.115:6381
121.4.126.115:6381 (4841f164...) -> 0 keys | 5461 slots | 1 slaves.
121.4.126.115:6383 (94187dcb...) -> 1 keys | 5461 slots | 1 slaves.
121.4.126.115:6382 (19e471a3...) -> 0 keys | 5462 slots | 1 slaves.
[OK] 1 keys in 3 masters.
0.00 keys per slot on average.
>>> Performing Cluster Check (using node 121.4.126.115:6381)
M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
   slots:[0-5460] (5461 slots) master
   1 additional replica(s)
S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
   slots: (0 slots) slave
   replicates 94187dcb0b28376f33e1169845e94af079f7241c
S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
   slots: (0 slots) slave
   replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
   slots:[10923-16383] (5461 slots) master
   1 additional replica(s)
S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
   slots: (0 slots) slave
   replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
   slots:[5461-10922] (5462 slots) master
   1 additional replica(s)
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.
root@VM-4-9-centos:/data# 
主从容错切换迁移案例
  1. 停止redis-node-1,docker stop redis-node-1

  2. 进入实例2查看集群信息redis-cli --cluster check 121.4.126.115:6382

    >>> Performing Cluster Check (using node 121.4.126.115:6382)
    M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
       slots:[5461-10922] (5462 slots) master
       1 additional replica(s)
    M: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
       slots:[0-5460] (5461 slots) master
    S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
       slots: (0 slots) slave
       replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
    S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
       slots: (0 slots) slave
       replicates 94187dcb0b28376f33e1169845e94af079f7241c
    M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
       slots:[10923-16383] (5461 slots) master
       1 additional replica(s)
    [OK] All nodes agree about slots configuration.
    >>> Check for open slots...
    >>> Check slots coverage...
    [OK] All 16384 slots covered.
    root@VM-4-9-centos:/data# 
    
    • 可以看到现在6385成为了主节点
  3. 还原之前的三主三从

    • 启动redis-node-1,docker start redis-node-1

    • 停止redis-node-5,docker stop redis-node-5

    • 再次启动redis-node-5,docker start redis-node-5

    • 查看集群状态

      root@VM-4-9-centos:/data# redis-cli --cluster check 121.4.126.115:6381
      121.4.126.115:6381 (4841f164...) -> 0 keys | 5461 slots | 1 slaves.
      121.4.126.115:6383 (94187dcb...) -> 1 keys | 5461 slots | 1 slaves.
      121.4.126.115:6382 (19e471a3...) -> 0 keys | 5462 slots | 1 slaves.
      [OK] 1 keys in 3 masters.
      0.00 keys per slot on average.
      >>> Performing Cluster Check (using node 121.4.126.115:6381)
      M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
         slots:[0-5460] (5461 slots) master
         1 additional replica(s)
      M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
         slots:[10923-16383] (5461 slots) master
         1 additional replica(s)
      M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
         slots:[5461-10922] (5462 slots) master
         1 additional replica(s)
      S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
         slots: (0 slots) slave
         replicates 94187dcb0b28376f33e1169845e94af079f7241c
      S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
         slots: (0 slots) slave
         replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
      S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
         slots: (0 slots) slave
         replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
      [OK] All nodes agree about slots configuration.
      >>> Check for open slots...
      >>> Check slots coverage...
      [OK] All 16384 slots covered.
      root@VM-4-9-centos:/data# 
      
主从扩容案例

在三主三从的基础上再添加一主一从

  1. 新建6387、6388连个Redis实例并启动

    docker run -d --name redis-node-7 --net host --privileged=true -v /data/redis/share/redis-node-7:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6387
    
    docker run -d --name redis-node-8 --net host --privileged=true -v /data/redis/share/redis-node-8:/data redis:6.0.8 --cluster-enabled yes --appendonly yes --port 6388
    
  2. 进入6387实例docker exec -it redis-node-7 /bin/bash

  3. 将新增节点6387加入集群

    • redis-cli --cluster add-node 自己实际IP地址:6387 自己实际IP地址:6381

      • 6387 就是将要作为master的新增节点
      • 6381 就是原来集群节点里面的领路人
      root@VM-4-9-centos:/data# redis-cli --cluster add-node 121.4.126.115:6387 121.4.126.115:6381
      >>> Adding node 121.4.126.115:6387 to cluster 121.4.126.115:6381
      >>> Performing Cluster Check (using node 121.4.126.115:6381)
      M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
         slots:[0-5460] (5461 slots) master
         1 additional replica(s)
      M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
         slots:[10923-16383] (5461 slots) master
         1 additional replica(s)
      M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
         slots:[5461-10922] (5462 slots) master
         1 additional replica(s)
      S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
         slots: (0 slots) slave
         replicates 94187dcb0b28376f33e1169845e94af079f7241c
      S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
         slots: (0 slots) slave
         replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
      S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
         slots: (0 slots) slave
         replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
      [OK] All nodes agree about slots configuration.
      >>> Check for open slots...
      >>> Check slots coverage...
      [OK] All 16384 slots covered.
      >>> Send CLUSTER MEET to node 121.4.126.115:6387 to make it join the cluster.
      [OK] New node added correctly.
      root@VM-4-9-centos:/data# 
      
  4. 查看集群情况redis-cli --cluster check 真实ip地址:6381(可等待一会儿)

    root@VM-4-9-centos:/data# redis-cli --cluster check 121.4.126.115:6381
    121.4.126.115:6381 (4841f164...) -> 0 keys | 5461 slots | 1 slaves.
    121.4.126.115:6383 (94187dcb...) -> 1 keys | 5461 slots | 1 slaves.
    121.4.126.115:6387 (2d1102c5...) -> 0 keys | 0 slots | 0 slaves.
    121.4.126.115:6382 (19e471a3...) -> 0 keys | 5462 slots | 1 slaves.
    [OK] 1 keys in 4 masters.
    0.00 keys per slot on average.
    >>> Performing Cluster Check (using node 121.4.126.115:6381)
    M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
       slots:[0-5460] (5461 slots) master
       1 additional replica(s)
    M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
       slots:[10923-16383] (5461 slots) master
       1 additional replica(s)
    M: 2d1102c57e683365d6568f83348390ea6972f0ab 121.4.126.115:6387
       slots: (0 slots) master
    M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
       slots:[5461-10922] (5462 slots) master
       1 additional replica(s)
    S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
       slots: (0 slots) slave
       replicates 94187dcb0b28376f33e1169845e94af079f7241c
    S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
       slots: (0 slots) slave
       replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
    S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
       slots: (0 slots) slave
       replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
    [OK] All nodes agree about slots configuration.
    >>> Check for open slots...
    >>> Check slots coverage...
    [OK] All 16384 slots covered.
    root@VM-4-9-centos:/data# 
    

    发现新master节点没有分配到槽位

  5. 重新分配槽位redis-cli --cluster reshard IP地址:端口号
    在这里插入图片描述

  6. 再次查看集群情况redis-cli --cluster check 121.4.126.115:6381

    root@VM-4-9-centos:/data# redis-cli --cluster check 121.4.126.115:6381
    121.4.126.115:6381 (4841f164...) -> 0 keys | 4096 slots | 1 slaves.
    121.4.126.115:6383 (94187dcb...) -> 1 keys | 4096 slots | 1 slaves.
    121.4.126.115:6387 (2d1102c5...) -> 0 keys | 4096 slots | 0 slaves.
    121.4.126.115:6382 (19e471a3...) -> 0 keys | 4096 slots | 1 slaves.
    [OK] 1 keys in 4 masters.
    0.00 keys per slot on average.
    >>> Performing Cluster Check (using node 121.4.126.115:6381)
    M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
       slots:[1365-5460] (4096 slots) master
       1 additional replica(s)
    M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
       slots:[12288-16383] (4096 slots) master
       1 additional replica(s)
    M: 2d1102c57e683365d6568f83348390ea6972f0ab 121.4.126.115:6387
       slots:[0-1364],[5461-6826],[10923-12287] (4096 slots) master
    M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
       slots:[6827-10922] (4096 slots) master
       1 additional replica(s)
    S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
       slots: (0 slots) slave
       replicates 94187dcb0b28376f33e1169845e94af079f7241c
    S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
       slots: (0 slots) slave
       replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
    S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
       slots: (0 slots) slave
       replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
    [OK] All nodes agree about slots configuration.
    >>> Check for open slots...
    >>> Check slots coverage...
    [OK] All 16384 slots covered.
    root@VM-4-9-centos:/data# 
    

    槽位分配说明:

    为什么6387是3个新的区间,以前的还是连续?
    重新分配成本太高,所以前3家各自匀出来一部分,从6381/6382/6383三个旧节点分别匀出1364个坑位给新节点6387

    在这里插入图片描述

  7. 为主节点6387分配从节点6388redis-cli --cluster add-node ip:新slave端口 ip:新master端口 --cluster-slave --cluster-master-id 新主机节点ID

    root@VM-4-9-centos:/data# redis-cli --cluster add-node 121.4.126.115:6388 121.4.126.115:6387 --cluster-slave --cluster-master-id 2d1102c57e683365d6568f83348390ea6972f0ab
    >>> Adding node 121.4.126.115:6388 to cluster 121.4.126.115:6387
    >>> Performing Cluster Check (using node 121.4.126.115:6387)
    M: 2d1102c57e683365d6568f83348390ea6972f0ab 121.4.126.115:6387
       slots:[0-1364],[5461-6826],[10923-12287] (4096 slots) master
    M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
       slots:[1365-5460] (4096 slots) master
       1 additional replica(s)
    S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
       slots: (0 slots) slave
       replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
    M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
       slots:[6827-10922] (4096 slots) master
       1 additional replica(s)
    S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
       slots: (0 slots) slave
       replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
    M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
       slots:[12288-16383] (4096 slots) master
       1 additional replica(s)
    S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
       slots: (0 slots) slave
       replicates 94187dcb0b28376f33e1169845e94af079f7241c
    [OK] All nodes agree about slots configuration.
    >>> Check for open slots...
    >>> Check slots coverage...
    [OK] All 16384 slots covered.
    >>> Send CLUSTER MEET to node 121.4.126.115:6388 to make it join the cluster.
    Waiting for the cluster to join
    
    >>> Configure node as replica of 121.4.126.115:6387.
    [OK] New node added correctly.
    root@VM-4-9-centos:/data# 
    
  8. 查看集群情况redis-cli --cluster check 121.4.126.115:6381

    在这里插入图片描述

主从缩容案例

去掉6387和6388实例

  1. 查看集群情况获得从机6388的节点IDredis-cli --cluster check 121.4.126.115:6381

    M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
       slots:[1365-5460] (4096 slots) master
       1 additional replica(s)
    M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
       slots:[12288-16383] (4096 slots) master
       1 additional replica(s)
    M: 2d1102c57e683365d6568f83348390ea6972f0ab 121.4.126.115:6387
       slots:[0-1364],[5461-6826],[10923-12287] (4096 slots) master
       1 additional replica(s)
    S: d2301451d974c61807d9f21d03834584a347b5ce 121.4.126.115:6388
       slots: (0 slots) slave
       replicates 2d1102c57e683365d6568f83348390ea6972f0ab
    M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
       slots:[6827-10922] (4096 slots) master
       1 additional replica(s)
    S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
       slots: (0 slots) slave
       replicates 94187dcb0b28376f33e1169845e94af079f7241c
    S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
       slots: (0 slots) slave
       replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
    S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
       slots: (0 slots) slave
       replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
    
  2. 从集群中移除6388从节点redis-cli --cluster del-node ip:从机端口 从机6388节点ID

    root@VM-4-9-centos:/data# redis-cli --cluster del-node 121.4.126.115:6388 d2301451d974c61807d9f21d03834584a347b5ce
    >>> Removing node d2301451d974c61807d9f21d03834584a347b5ce from cluster 121.4.126.115:6388
    >>> Sending CLUSTER FORGET messages to the cluster...
    >>> Sending CLUSTER RESET SOFT to the deleted node.
    root@VM-4-9-centos:/data# 
    
  3. 查看集群情况redis-cli --cluster check 121.4.126.115:6381(从8个节点变成了7个节点)

    root@VM-4-9-centos:/data# redis-cli --cluster check 121.4.126.115:6381
    121.4.126.115:6381 (4841f164...) -> 0 keys | 4096 slots | 1 slaves.
    121.4.126.115:6383 (94187dcb...) -> 1 keys | 4096 slots | 1 slaves.
    121.4.126.115:6387 (2d1102c5...) -> 0 keys | 4096 slots | 0 slaves.
    121.4.126.115:6382 (19e471a3...) -> 0 keys | 4096 slots | 1 slaves.
    [OK] 1 keys in 4 masters.
    0.00 keys per slot on average.
    >>> Performing Cluster Check (using node 121.4.126.115:6381)
    M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
       slots:[1365-5460] (4096 slots) master
       1 additional replica(s)
    M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
       slots:[12288-16383] (4096 slots) master
       1 additional replica(s)
    M: 2d1102c57e683365d6568f83348390ea6972f0ab 121.4.126.115:6387
       slots:[0-1364],[5461-6826],[10923-12287] (4096 slots) master
    M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
       slots:[6827-10922] (4096 slots) master
       1 additional replica(s)
    S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
       slots: (0 slots) slave
       replicates 94187dcb0b28376f33e1169845e94af079f7241c
    S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
       slots: (0 slots) slave
       replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
    S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
       slots: (0 slots) slave
       replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
    [OK] All nodes agree about slots configuration.
    >>> Check for open slots...
    >>> Check slots coverage...
    [OK] All 16384 slots covered.
    root@VM-4-9-centos:/data# 
    
  4. 将6387主节点的槽位清空:重新分配,此次案例将6387的槽位全部分给6381主节点redis-cli --cluster reshard 121.4.126.115:6381

    在这里插入图片描述

  5. 再次查看节点情况redis-cli --cluster check 121.4.126.115:6381(可以看到6387的槽位全部移给了6381节点)

    root@VM-4-9-centos:/data# redis-cli --cluster check 121.4.126.115:6381
    121.4.126.115:6381 (4841f164...) -> 0 keys | 8192 slots | 1 slaves.
    121.4.126.115:6383 (94187dcb...) -> 1 keys | 4096 slots | 1 slaves.
    121.4.126.115:6387 (2d1102c5...) -> 0 keys | 0 slots | 0 slaves.
    121.4.126.115:6382 (19e471a3...) -> 0 keys | 4096 slots | 1 slaves.
    [OK] 1 keys in 4 masters.
    0.00 keys per slot on average.
    >>> Performing Cluster Check (using node 121.4.126.115:6381)
    M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
       slots:[0-6826],[10923-12287] (8192 slots) master
       1 additional replica(s)
    M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
       slots:[12288-16383] (4096 slots) master
       1 additional replica(s)
    M: 2d1102c57e683365d6568f83348390ea6972f0ab 121.4.126.115:6387
       slots: (0 slots) master
    M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
       slots:[6827-10922] (4096 slots) master
       1 additional replica(s)
    S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
       slots: (0 slots) slave
       replicates 94187dcb0b28376f33e1169845e94af079f7241c
    S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
       slots: (0 slots) slave
       replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
    S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
       slots: (0 slots) slave
       replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
    [OK] All nodes agree about slots configuration.
    >>> Check for open slots...
    >>> Check slots coverage...
    [OK] All 16384 slots covered.
    root@VM-4-9-centos:/data# 
    
  6. 将6387主节点从集群中移除redis-cli --cluster del-node ip:端口 6387节点ID

    root@VM-4-9-centos:/data# redis-cli --cluster del-node 121.4.126.115:6387 2d1102c57e683365d6568f83348390ea6972f0ab
    >>> Removing node 2d1102c57e683365d6568f83348390ea6972f0ab from cluster 121.4.126.115:6387
    >>> Sending CLUSTER FORGET messages to the cluster...
    >>> Sending CLUSTER RESET SOFT to the deleted node.
    root@VM-4-9-centos:/data# 
    
  7. 查看集群情况redis-cli --cluster check 121.4.126.115:6381(恢复成了三主三从)

    root@VM-4-9-centos:/data# redis-cli --cluster check 121.4.126.115:6381
    121.4.126.115:6381 (4841f164...) -> 0 keys | 8192 slots | 1 slaves.
    121.4.126.115:6383 (94187dcb...) -> 1 keys | 4096 slots | 1 slaves.
    121.4.126.115:6382 (19e471a3...) -> 0 keys | 4096 slots | 1 slaves.
    [OK] 1 keys in 3 masters.
    0.00 keys per slot on average.
    >>> Performing Cluster Check (using node 121.4.126.115:6381)
    M: 4841f1647bab764ae048e50ec4283b01d8010b3b 121.4.126.115:6381
       slots:[0-6826],[10923-12287] (8192 slots) master
       1 additional replica(s)
    M: 94187dcb0b28376f33e1169845e94af079f7241c 121.4.126.115:6383
       slots:[12288-16383] (4096 slots) master
       1 additional replica(s)
    M: 19e471a30df72ac8d83729814aaf2286e2c5315f 121.4.126.115:6382
       slots:[6827-10922] (4096 slots) master
       1 additional replica(s)
    S: 2c89b726a7ac9e2e47d998849eb1f87d7e9efa84 121.4.126.115:6384
       slots: (0 slots) slave
       replicates 94187dcb0b28376f33e1169845e94af079f7241c
    S: 1b6d2ddba747ddf8f08a3afe99cac5c02d911000 121.4.126.115:6385
       slots: (0 slots) slave
       replicates 4841f1647bab764ae048e50ec4283b01d8010b3b
    S: 2c4f14ea080639699d37fc44955043b66730582d 121.4.126.115:6386
       slots: (0 slots) slave
       replicates 19e471a30df72ac8d83729814aaf2286e2c5315f
    [OK] All nodes agree about slots configuration.
    >>> Check for open slots...
    >>> Check slots coverage...
    [OK] All 16384 slots covered.
    root@VM-4-9-centos:/data# 
    

文章来源:https://blog.csdn.net/weixin_52164430/article/details/135360278
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