1. 概述说明

    

   说明：本次实验采用c1、c2、c3三台虚拟机完成，每台服务器上都部署一个master、一个slave和一个sentinel。当某主节点的挂了，相应的从节点替位；当某主节点及主节点对应的从节点同时挂了，将造成数据的丢失！故生产环境都采用一主多从的集群模式！

2. 搭建环境

   服务器信息如下：

   c1 192.168.10.11

   c2 192.168.10.12

   c3 192.168.10.13

    

   每台需要部署redis的服务器上配置系统参数，执行以下脚本

   # cat xitongcanshu.sh

   #!/bin/bash

   echo 'net.core.somaxconn=512' >> /etc/sysctl.conf

   echo 'vm.overcommit_memory=1' >> /etc/sysctl.conf

   echo never > /sys/kernel/mm/transparent_hugepage/enabled

   echo 'echo never > /sys/kernel/mm/transparent_hugepage/enabled' >> /etc/rc.local

   chmod +x /etc/rc.d/rc.local

   sysctl -p

   cat >> /etc/security/limits.conf << EOF

   * soft nofile 65535

   * hard nofile 65535

   * soft nproc 65535

   * hard nproc 65535

   EOF

   ulimit -SHn 65535

   ulimit -n

3. redis

   说明：本次实验在c1、c2、c3三台服务器上分别部署一个master和一个slave！

   [root@c1 ~]# wget http://download.redis.io/releases/redis-4.0.9.tar.gz

   [root@c1 ~]# tar xf redis-4.0.9.tar.gz -C /usr/local/

   [root@c1 ~]# ln -sv /usr/local/redis-4.0.9 /usr/local/redis

   [root@c1 ~]# yum -y install tcl openssl-devel zlib-devel

   [root@c1 /usr/local/redis]# make && make PREFIX=/usr/local/redis-4.0.9/ install

   [root@c1 /usr/local/redis]# make test

   [root@c1 ~]# mkdir -pv /etc/redis-cluster/{7001,7002} /var/log/redis

   # 拷贝默认配置文件并根据需求修改，因实验环境，故采用简洁配置，如下：

   [root@c1 ~]# cat /etc/redis-cluster/7001/redis.conf

   port 7001

   bind 192.168.10.11

   cluster-enabled yes

   cluster-config-file /etc/redis-cluster/7001/nodes.conf

   logfile /var/log/redis/redis_7001.log

   cluster-node-timeout 5000

   appendonly yes

   daemonize yes

   [root@c1 ~]# cat /etc/redis-cluster/7002/redis.conf

   port 7002

   bind 192.168.10.12

   cluster-enabled yes

   cluster-config-file /etc/redis-cluster/7002/nodes.conf

   logfile /var/log/redis/redis_7002.log

   cluster-node-timeout 5000

   appendonly yes

   daemonize yes

    

   # 启动

   [root@c1 ~]# /usr/local/redis/bin/redis-server /etc/redis-cluster/7001/redis.conf

   [root@c1 ~]# /usr/local/redis/bin/redis-server /etc/redis-cluster/7002/redis.conf

    

   # c2、c3服务器也进行以上操作，配置只需修改对应的ip即可！

4. cluster

   说明：本次实验主从关系如下：

   c1 master --- c2 slave M/S 1

   c2 master --- c3 slave M/S 2

   c3 master --- c1 slave M/S 3

    

   # 说明：框内内容是编译安装ruby工具，以便能成功执行redis-trib.rb创建集群，；yum方式安装ruby可能版本较低！

   [root@c1 ~]# wget https://cache.ruby-lang.org/pub/ruby/2.5/ruby-2.5.1.tar.gz

   [root@c1 ~]# wget https://rubygems.org/downloads/redis-4.0.0.gem

   [root@c1 ~]# tar -xf ruby-2.5.1.tar.gz -C /usr/local/

   [root@c1 /usr/local/ruby-2.5.1]# ./configure -prefix=/usr/local/ruby-2.5.1

   [root@c1 /usr/local/ruby-2.5.1]# make && make install

   [root@c1 ~]# ln -sv /usr/local/ruby-2.5.1/bin/gem /usr/bin/gem

   [root@c1 ~]# ln -sv /usr/local/ruby-2.5.1/bin/ruby /usr/bin/ruby

   # 在配置文件/usr/local/ruby-2.5.1/ext/openssl/Makefile和/usr/local/ruby-2.5.1/ext/zlib/Makefile中的定义变量处加上如下红色行，若存在相应变量的定义请注释；

   srcdir = .

   top_srcdir = ../..

   topdir = /usr/local/ruby-2.5.1/include/ruby-2.5.0

   [root@c1 /usr/local/ruby-2.5.1/ext/zlib]# ruby extconf.rb

   [root@c1 /usr/local/ruby-2.5.1/ext/zlib]# make && make install

   [root@c1 /usr/local/ruby-2.5.1/ext/openssl]# ruby extconf.rb

   [root@c1 /usr/local/ruby-2.5.1/ext/openssl]# make && make install

   [root@c1 ~]# gem install -l redis-4.0.0.gem

    

   # 创建集群，格式：主 主 主 从 从 从

   [root@c1 ~]# /usr/local/redis/src/redis-trib.rb create --replicas 1 192.168.10.11:7001 192.168.10.12:7001 192.168.10.13:7001 192.168.10.12:7002 192.168.10.13:7002 192.168.10.11:7002

   >>> Creating cluster

   >>> Performing hash slots allocation on 6 nodes...

   Using 3 masters:

   192.168.10.11:7001

   192.168.10.12:7001

   192.168.10.13:7001

   Adding replica 192.168.10.12:7002 to 192.168.10.11:7001

   Adding replica 192.168.10.13:7002 to 192.168.10.12:7001

   Adding replica 192.168.10.11:7002 to 192.168.10.13:7001

   M: 440541e2a3235205bf190336a1f37f127d18bf60 192.168.10.11:7001

   slots:0-5460 (5461 slots) master

   M: c588a93825de6e0e6730a8bbb072684619201803 192.168.10.12:7001

   slots:5461-10922 (5462 slots) master

   M: 9ba21cfda0fed2d9013103e934f199a247c378ef 192.168.10.13:7001

   slots:10923-16383 (5461 slots) master

   S: f07abd56170635aaad5166bd38af9f7267834ca7 192.168.10.12:7002

   replicates 440541e2a3235205bf190336a1f37f127d18bf60

   S: 1aa03c91fc62ac72aeccf349d040f32ae190120b 192.168.10.13:7002

   replicates c588a93825de6e0e6730a8bbb072684619201803

   S: ff7e453f9ad5d2db2c7867893700fec033767bd9 192.168.10.11:7002

   replicates 9ba21cfda0fed2d9013103e934f199a247c378ef

   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 192.168.10.11:7001)

   M: 440541e2a3235205bf190336a1f37f127d18bf60 192.168.10.11:7001

   slots:0-5460 (5461 slots) master

   1 additional replica(s)

   S: 1aa03c91fc62ac72aeccf349d040f32ae190120b 192.168.10.13:7002

   slots: (0 slots) slave

   replicates c588a93825de6e0e6730a8bbb072684619201803

   S: ff7e453f9ad5d2db2c7867893700fec033767bd9 192.168.10.11:7002

   slots: (0 slots) slave

   replicates 9ba21cfda0fed2d9013103e934f199a247c378ef

   M: 9ba21cfda0fed2d9013103e934f199a247c378ef 192.168.10.13:7001

   slots:10923-16383 (5461 slots) master

   1 additional replica(s)

   M: c588a93825de6e0e6730a8bbb072684619201803 192.168.10.12:7001

   slots:5461-10922 (5462 slots) master

   1 additional replica(s)

   S: f07abd56170635aaad5166bd38af9f7267834ca7 192.168.10.12:7002

   slots: (0 slots) slave

   replicates 440541e2a3235205bf190336a1f37f127d18bf60

   [OK] All nodes agree about slots configuration.

   >>> Check for open slots...

   >>> Check slots coverage...

   [OK] All 16384 slots covered.

    

   # 查看节点信息

   [root@c1 ~]# /usr/local/redis/bin/redis-cli -h 192.168.10.13 -p 7001

   192.168.10.13:7001> cluster nodes

   ff7e453f9ad5d2db2c7867893700fec033767bd9 192.168.10.11:7002@17002 slave 9ba21cfda0fed2d9013103e934f199a247c378ef 0 1527578162996 6 connected

   1aa03c91fc62ac72aeccf349d040f32ae190120b 192.168.10.13:7002@17002 slave c588a93825de6e0e6730a8bbb072684619201803 0 1527578161483 5 connected

   440541e2a3235205bf190336a1f37f127d18bf60 192.168.10.11:7001@17001 master - 0 1527578162000 1 connected 0-5460

   f07abd56170635aaad5166bd38af9f7267834ca7 192.168.10.12:7002@17002 slave 440541e2a3235205bf190336a1f37f127d18bf60 0 1527578161000 4 connected

   c588a93825de6e0e6730a8bbb072684619201803 192.168.10.12:7001@17001 master - 0 1527578162491 2 connected 5461-10922

   9ba21cfda0fed2d9013103e934f199a247c378ef 192.168.10.13:7001@17001 myself,master - 0 1527578162000 3 connected 10923-16383

5. sentinel

   前言

       Redis-Sentinel是官方推荐的高可用（HA）解决方案，本身也是一个独立运行的进程，它能监控多个master-slave集群。为防止单点故障，可对sentinel进行集群化。其主要功能如下：

   1. 监控：sentinel不断的检查master和slave的活性；
   2. 通知：当发现redis节点故障，可通过API发出通知；
   3. 自动故障转移：当一个master节点故障时，能够从众多slave中选举一个作为新的master，同时其它slave节点也将自动将所追随的master的地址改为新master的地址；
   4. 配置提供者：哨兵作为redis客户端发现的权威来源：客户端连接到哨兵请求当前可靠的master地址，若发生故障，哨兵将报告新地址。

    

   配置

   说明：本次实验将三个哨兵分别部署在c1、c2、c3三台服务器上！

   [root@c1 ~]# cp /usr/local/redis/sentinel.conf /etc/redis-cluster/

   [root@c1 ~]# cat /etc/redis-cluster/sentinel.conf

   protected-mode no

   port 27001

   daemonize yes

   logfile "/var/log/sentinel.log"

   sentinel monitor mymaster1 192.168.10.11 7001 2

   sentinel monitor mymaster2 192.168.10.12 7001 2

   sentinel monitor mymaster3 192.168.10.13 7001 2

   sentinel down-after-milliseconds mymaster1 10000

   sentinel down-after-milliseconds mymaster2 10000

   sentinel down-after-milliseconds mymaster3 10000

   sentinel parallel-syncs mymaster1 1

   sentinel parallel-syncs mymaster2 1

   sentinel parallel-syncs mymaster3 1

   sentinel failover-timeout mymaster1 15000

   sentinel failover-timeout mymaster2 15000

   sentinel failover-timeout mymaster3 15000

    

   # 启动哨兵

   [root@c1 ~]# /usr/local/redis/bin/redis-sentinel /etc/redis-cluster/sentinel.conf

    

   # c2、c3服务器也进行以上操作，配置只需修改对应的端口即可！

    

   说明：启动哨兵后，配置文件会根据监控信息自动发生相应的变化，如下：

   [root@c1 ~]# cat /etc/redis-cluster/sentinel.conf

   protected-mode no

   port 27001

   daemonize yes

   logfile "/var/log/sentinel.log"

   sentinel myid e3733670b609b65e520b293789e4fbf10236089c

   sentinel monitor mymaster3 192.168.10.13 7001 2

   sentinel down-after-milliseconds mymaster3 10000

   sentinel failover-timeout mymaster3 15000

   sentinel config-epoch mymaster3 0

   sentinel leader-epoch mymaster3 0

   sentinel known-slave mymaster3 192.168.10.11 7002

   sentinel monitor mymaster1 192.168.10.11 7001 2

   sentinel down-after-milliseconds mymaster1 10000

   sentinel failover-timeout mymaster1 15000

   sentinel config-epoch mymaster1 0

   sentinel leader-epoch mymaster1 0

   # Generated by CONFIG REWRITE

   dir "/etc/redis-cluster"

   sentinel known-slave mymaster1 192.168.10.12 7002

   sentinel monitor mymaster2 192.168.10.12 7001 2

   sentinel down-after-milliseconds mymaster2 10000

   sentinel failover-timeout mymaster2 15000

   sentinel config-epoch mymaster2 0

   sentinel leader-epoch mymaster2 0

   sentinel known-slave mymaster2 192.168.10.13 7002

   sentinel current-epoch 0

6. 故障模拟

   # 通过sentinel日志查看信息，图中可看出192.168.10.11 7001为 master，其相应的从为192.168.10.12 7002;

    

   # 手动停止master 192.168.10.11 7001，slave 192.168.10.12 7002升为主

   [root@c1 ~]# ps -ef |grep redis

   root 4243 1 0 03:05 ? 00:00:23 /usr/local/redis/bin/redis-server 192.168.10.11:7001 [cluster]

   root 4245 1 0 03:05 ? 00:00:23 /usr/local/redis/bin/redis-server 192.168.10.11:7002 [cluster]

   root 8472 1 1 03:45 ? 00:00:07 /usr/local/redis/bin/redis-sentinel *:27001 [sentinel]

   [root@c1 ~]# kill 4243

   # 日志输出如下：

    

   # 登陆查看nodes信息

   # /usr/local/redis/bin/redis-cli -h 192.168.10.13 -p 7001

    

   # 将192.168.10.11 7001的redis启动

   [root@c1 ~]# /usr/local/redis/bin/redis-server /etc/redis-cluster/7001/redis.conf

    

   # sentinel刷新日志

    

   # 再次查看nodes信息，192.168.10.11 7001 已经变为192.168.10.12 7002的slave

7. 报错说明

   问题描述

       在执行命令# /usr/local/redis/src/redis-trib.rb create --replicas 1 *** 创建集群时报错如下：

   >>> Creating cluster

   [ERR] Node 192.168.10.11:7001 is not empty. Either the node already knows other nodes (check with CLUSTER NODES) or contains some key in database 0.

    

   问题解决

   1. 将节点下aof、rdb等本地备份删除；
   2. 删除node集群配置文件，即redis.conf中cluster-config-file对应的文件；

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