1、客户端登陆

 测试链接redis，存取数据(链接集群中任意一台机器就可以。)
 存：
 [root@redis-cluster1 src]# ./redis-cli -h 192.168.116.172 -c -p 7000
 192.168.116.172:7000> ping
 PONG
 192.168.116.172:7000> set name qianfeng
 -> Redirected to slot [5798] located at 192.168.116.173:7002
 OK
 192.168.116.173:7002>
 
 读
 [root@redis-cluster3 src]# ./redis-cli -h 192.168.116.173 -c -p 7002
 192.168.116.173:7002> ping 
 PONG
 192.168.116.173:7002> get name
 "qianfeng"
 192.168.116.173:7002> exists name  #查看某一个key是否存在
 (integer) 1

2、集群添加节点

 准备工作:
 1.新准备一台机器，修改主机名，关闭防火墙和selinux。
 2.安装相同版本redis，单机多实例。配置主从端口配置文件。
 新准备cluster4，第一列为master第二列为slave。 
 192.168.116.175 redis-cluster4  7006 7007
 [root@redis-cluster4 ~]# mkdir /data
 [root@redis-cluster4 ~]# yum -y install gcc automake autoconf libtool make
 [root@redis-cluster4 ~]# wget https://download.redis.io/releases/redis-6.2.0.tar.gz
 [root@redis-cluster4 ~]# tar xzvf redis-6.2.0.tar.gz -C /data/
 [root@redis-cluster4 ~]# cd /data/
 [root@redis-cluster4 data]# mv redis-6.2.0/ redis
 [root@redis-cluster4 data]# cd redis/
 [root@redis-cluster4 redis]# make    #编译
 [root@redis-cluster4 redis]# mkdir data  #创建数据目录
 [root@redis-cluster4 redis]# mkdir cluster
 [root@redis-cluster4 redis]# mkdir cluster/{7006,7007}  #创建集群节点
 [root@redis-cluster4 redis]# cp redis.conf cluster/7006/
 [root@redis-cluster4 redis]# cp redis.conf cluster/7007/
 开始修改配置文件略...和之前一样，注意修改不一样的地方:端口、ip、pid文件...
 启动
 [root@redis-cluster4 src]# ./redis-server ../cluster/7006/redis.conf 
 [root@redis-cluster4 src]# ./redis-server ../cluster/7007/redis.conf
 ?
 1.都准备好之后，开始添加节点：将cluster4添加到集群中
 [root@redis-cluster4 src]# ./redis-cli --cluster add-node 192.168.116.175:7006 192.168.116.172:7000
 >>> Adding node 192.168.116.175:7006 to cluster 192.168.116.172:7000
 ......
 >>> Check for open slots...
 >>> Check slots coverage...
 [OK] All 16384 slots covered.
 >>> Send CLUSTER MEET to node 192.168.116.175:7006 to make it join the cluster.
 [OK] New node added correctly.
 ?
 查看集群节点信息(随便登陆一个客户端即可)
 [root@redis-cluster1 src]# ./redis-cli -h 192.168.116.172 -c -p 7000
 192.168.116.172:7000> CLUSTER nodes

 详细解释：
 runid: 该行描述的节点的id。
 ip:prot: 该行描述的节点的ip和port
 flags: 逗号分隔的标记位，可能的值有：
 1.master: 该行描述的节点是master
 2.slave: 该行描述的节点是slave
 3.fail?:该行描述的节点可能不可用
 4.fail:该行描述的节点不可用（故障）
 master_runid: 该行描述的节点的master的id,如果本身是master则显示-
 ping-sent: 最近一次发送ping的Unix时间戳，0表示未发送过
 pong-recv：最近一次收到pong的Unix时间戳，0表示未收到过
 config-epoch: 主从切换的次数
 link-state: 连接状态，connnected 和 disconnected
 hash slot: 该行描述的master中存储的key的hash的范围
 2.给新节点hash槽分配
 需要给新节点进行hash槽分配，这样该主节才可以存储数据，（如果有数据记得提前先将数据同步然后在从其他节点迁移槽到新节点。）
 [root@redis-cluster1 src]# ./redis-cli --cluster reshard 192.168.116.175:7006
 >>> Performing Cluster Check (using node 192.168.116.175:7006)
 ......
 [OK] All nodes agree about slots configuration.
 >>> Check for open slots...
 >>> Check slots coverage...
 [OK] All 16384 slots covered.
 How many slots do you want to move (from 1 to 16384)? 4000 #输入要分配的槽数量 
 What is the receiving node ID?  828c48dc72d52ff5be972512d3d87b70236af87c #输入接收槽的节点id,通过cluster nodes 查看新增的192.168.116.175:7006 的id
 ?
 Please enter all the source node IDs.
   Type 'all' to use all the nodes as source nodes for the hash slots.
   Type 'done' once you entered all the source nodes IDs.
 输入： all
 然后输入输入yes确认
 ?
 此时再通过cluster nodes查看节点，可以看到新节点分配的槽为0-1332 5461-6794 10923-12255
 [root@redis-cluster1 src]# ./redis-cli -h 192.168.116.172 -c -p 7000
 192.168.116.172:7000> CLUSTER nodes

 3.给新添加的主节点添加对用的从节点：
 [root@redis-cluster4 src]# ./redis-cli --cluster add-node 192.168.116.175:7007 192.168.116.175:7006 --cluster-slave --cluster-master-id 308320db4284c9b203aff1d3d9a145616856f681 #master的id
 >>> Adding node 192.168.116.175:7007 to cluster 192.168.116.175:7006
 >>> Performing Cluster Check (using node 192.168.116.175:7006)
 ......
 [OK] All nodes agree about slots configuration.
 >>> Check for open slots...
 >>> Check slots coverage...
 [OK] All 16384 slots covered.
 >>> Send CLUSTER MEET to node 192.168.116.175:7007 to make it join the cluster.
 Waiting for the cluster to join
 ?
 >>> Configure node as replica of 192.168.116.175:7006.
 [OK] New node added correctly.
 ?
 查看集群信息
 192.168.116.172:7000> CLUSTER nodes

 4.平衡各个主节点的槽：
 [root@redis-cluster1 src]# ./redis-cli --cluster rebalance --cluster-threshold 1 192.168.116.172:7000
 >>> Performing Cluster Check (using node 192.168.116.172:7000)
 [OK] All nodes agree about slots configuration.
 >>> Check for open slots...
 >>> Check slots coverage...
 [OK] All 16384 slots covered.
 >>> Rebalancing across 4 nodes. Total weight = 4.00
 Moving 32 slots from 192.168.116.174:7004 to 192.168.116.175:7006
 ################################
 Moving 32 slots from 192.168.116.173:7002 to 192.168.116.175:7006
 ################################
 Moving 32 slots from 192.168.116.172:7000 to 192.168.116.175:7006
 ################################
 ?
 登陆测试：
 [root@redis-cluster1 src]# ./redis-cli -h 192.168.116.175 -c -p 7007
 192.168.116.175:7007> ping
 PONG
 192.168.116.175:7007> get name 
 -> Redirected to slot [5798] located at 192.168.116.175:7006
 "qianfeng"

3、删除节点

 #注意:这个地方需要提一下的就是
 如果要下线节点6，节点7，请务必先下线从节点，并且节点6的slot的迁移到其他节点了，如果先线下节点6的话 会发产生故障切换，节点7成主节点了
 在移除某个redis节点之前，首先不能在登入该节点当中，否则不能正常移除该节点.
 ?
 1.退出所有链接的客户端，然后在任意一台机器执行
 [root@redis-cluster1 src]# ./redis-cli --cluster del-node 192.168.116.175:7007 dbad32bd47cc177de61109b96447d1f1ef6db2fc #该节点的id
 >>> Removing node dbad32bd47cc177de61109b96447d1f1ef6db2fc from cluster 192.168.116.175:7007
 >>> Sending CLUSTER FORGET messages to the cluster...
 >>> Sending CLUSTER RESET SOFT to the deleted node.
 ?
 [root@redis-cluster1 src]# ./redis-cli -h 192.168.116.172 -c -p 7000
 192.168.116.172:7000> CLUSTER NODES

 2.删除主节点：带有槽的节点
 查看每个节点槽的数量
 [root@redis-cluster1 src]# ./redis-cli --cluster info 192.168.116.172:7000
 192.168.116.172:7000 (de5b4b2f...) -> 0 keys | 4096 slots | 1 slaves.
 192.168.116.173:7002 (e0370608...) -> 0 keys | 4096 slots | 1 slaves.
 192.168.116.174:7004 (60e37557...) -> 0 keys | 4096 slots | 1 slaves.
 192.168.116.175:7006 (308320db...) -> 2 keys | 4096 slots | 0 slaves.
 [OK] 2 keys in 4 masters.
 ?
 要删除的当前主节点哈希槽状态：0-1364 5461-6826 10923-12287
 共有哈希槽=1365 + 1366 + 1365 = 4096个
 ?
 ?
 1.将6节点上面的槽迁移到其他节点：
 ip+port：要移除的节点
 cluster-from:移除节点的id
 cluster-to:接受槽主节点的id，需要将4096平均移动到不同的主节点，需要写不同接受槽的主节点id
 cluster-slots:移除槽的数量
 [root@redis-cluster1 src]# ./redis-cli --cluster reshard 192.168.116.175:7006 --cluster-from 308320db4284c9b203aff1d3d9a145616856f681 --cluster-to e0370608cd33ddf5bb6de48b5627799e181de3b6 --cluster-slots 1365 --cluster-yes
 ?
 [root@redis-cluster1 src]# ./redis-cli --cluster reshard 192.168.116.175:7006 --cluster-from 308320db4284c9b203aff1d3d9a145616856f681 --cluster-to de5b4b2f6a559362ed56d4de1e3994fd529917b5 --cluster-slots 1366 --cluster-yes
 ?
 [root@redis-cluster1 src]# ./redis-cli --cluster reshard 192.168.116.175:7006 --cluster-from 308320db4284c9b203aff1d3d9a145616856f681 --cluster-to 60e3755761c9cbdacb183f59e3d6205da5335e86 --cluster-slots 1365 --cluster-yes
 ?
 查看节点信息
 192.168.116.173:7002> CLUSTER nodes

可以看到已经没有槽了。

 如果报错：
 [root@redis-cluster1 src]# ./redis-cli --cluster del-node 192.168.116.175:7006 308320db4284c9b203aff1d3d9a145616856f681
 >>> Removing node 308320db4284c9b203aff1d3d9a145616856f681 from cluster 192.168.116.175:7006
 [ERR] Node 192.168.116.175:7006 is not empty! Reshard data away and try again.
 
 需要重新查看一下槽有没有全部移动完成。如果没有需要重新指定数量移动。这是因为还有槽不能直接移除master。
 3.删除master节点
 [root@redis-cluster1 src]# ./redis-cli --cluster del-node 192.168.116.175:7006 308320db4284c9b203aff1d3d9a145616856f681
 >>> Removing node 308320db4284c9b203aff1d3d9a145616856f681 from cluster 192.168.116.175:7006
 >>> Sending CLUSTER FORGET messages to the cluster...
 >>> Sending CLUSTER RESET SOFT to the deleted node.
 
 查看集群信息：
 192.168.116.173:7002> CLUSTER nodes

可以看到变成了3主3从