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redis集群（redis + cluster + sentinel）

日期：2018-05-29点击：494收藏

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！
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
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！
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
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
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
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；