Redis集群管理：在线伸缩扩展、故障转移

柔光的暖阳◎ 2023-06-23 08:55 4阅读 0赞

## 实验环境 ##

主机名        IP              端口
    node1    192.168.14.210    7001、8001
    node2    192.168.14.211    7002、8002
    node3    192.168.14.212    7003、8003

前提：已经部署集群，查看[https://blog.csdn.net/tladagio/article/details/103580641][https_blog.csdn.net_tladagio_article_details_103580641]

## 一、增加节点 ##

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70][]

1、根据上篇文章在node4新增一个节点，然后启动redis

[root@node4 ~]# redis-server /usr/local/redis/cluster/redis_7004.conf 
    [root@node4 ~]# redis-server /usr/local/redis/cluster/redis_8004.conf

2、新增一个master节点7004（add-node       new\_host:new\_port existing\_host:existing\_port）

[root@node4 ~]# redis-cli -a 123456 --cluster add-node 192.168.14.216:7004 192.168.14.210:7001

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 1][]

3、node1查看集群状态，

![20191218143324621.png][]

当添加节点成功以后，新增的节点不会有任何数据，因为它没有分配任何的slot(hash槽)。我们需要为新节点手工分配slot。

4、给node4分配slot槽

[root@node1 ~]# redis-cli -a 123456 --cluster reshard 192.168.14.216:7004

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 2][]

5、node1节点再次查看集群状态

![20191218150935144.png][]

6、新增一个slave节点8004

[root@node1 ~]# redis-cli -a 123456 --cluster add-node 192.168.14.216:8004 192.168.14.210:7001 --cluster-slave

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 3][]

7、查看集群状态

![20191218151515837.png][]

## 二、删除节点 ##

不能直接删除有数据的master节点，因为主节点的里面分配了slot 槽，所以我们这里必须先把7004里的slot 槽放入到其他的可用主节点中去，然后再进行移除节点操作才行，不然会出现数据丢失问题

1、在删除node4的master节点之前，先把数据移走

[root@node1 ~]# redis-cli -a 123456 --cluster reshard 192.168.14.216:7004

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 4][]

2、查看集群状态

![20191218153424333.png][]

3、可以删除节点

[root@node1 ~]# redis-cli -a 123456 --cluster del-node 192.168.14.216:7004 f0664536e57a84ea93c5550fe7c7328aa741dbf4

![20191218153703467.png][]

原7004的slave节点自动变为7001的slave节点

![2019121815391046.png][]

## 三、故障自动转移 ##

![20191218154748662.png][]

1、手动停掉node1的master节点7001，模拟故障

[root@node1 ~]# redis-cli -c -h 192.168.14.210 -p 7001 -a 123456 shutdown

2、查看集群状态，7001已经故障。8004自动切换为master节点，8002变为8004的slave节点

![20191218155058575.png][]

## 四、恢复故障 ##

1、启动7001节点

[root@node1 ~]# redis-server /usr/local/redis/cluster/redis_7001.conf

2、原master7001节点恢复之后，不会抢占master节点，而是变为slave节点。

![20191218155754281.png][]

3、再次查看之前设定的值依然存在

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3RsYWRhZ2lv_size_16_color_FFFFFF_t_70 5][]

至此，集群在线伸缩扩展，故障转移完成。

[https_blog.csdn.net_tladagio_article_details_103580641]: https://blog.csdn.net/tladagio/article/details/103580641
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[20191218150935144.png]: https://img-blog.csdnimg.cn/20191218150935144.png
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[20191218151515837.png]: https://img-blog.csdnimg.cn/20191218151515837.png
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[20191218153424333.png]: https://img-blog.csdnimg.cn/20191218153424333.png
[20191218153703467.png]: https://img-blog.csdnimg.cn/20191218153703467.png
[2019121815391046.png]: https://img-blog.csdnimg.cn/2019121815391046.png
[20191218154748662.png]: https://img-blog.csdnimg.cn/20191218154748662.png
[20191218155058575.png]: https://img-blog.csdnimg.cn/20191218155058575.png
[20191218155754281.png]: https://img-blog.csdnimg.cn/20191218155754281.png
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