线上的统一聊天和推送项目使用的是redis主从,redis版本2.8.6

redis主从和mysql主从目的差不多,但redis主从配置很简单,主要在从节点配置文件指定主节点ip和端口:slaveof 192.168.1.197 6379,然后启动主从,主从就搭建好了redis主从中如果主节点发生故障,不会自动切换,需要借助redis的Sentinel或者keepalive来实现主的故障转移

redis集群是一个无中心的分布式redis存储架构,可以在多个节点之间进行数据共享,解决了redis高可用、可扩展等问题,redis集群提供了以下两个好处
1、将数据自动切分(split)到多个节点
2、当集群中的某一个节点故障时,redis还可以继续处理客户端的请求。
一个 Redis 集群包含 16384 个哈希槽(hash slot),数据库中的每个数据都属于这16384个哈希槽中的一个。集群使用公式 CRC16(key) % 16384 来计算键 key 属于哪个槽。集群中的每一个节点负责处理一部分哈希槽。
集群中的主从复制
集群中的每个节点都有1个至N个复制品,其中一个为主节点,其余的为从节点,如果主节点下线了,集群就会把这个主节点的一个从节点设置为新的主节点,继续工作。这样集群就不会因为一个主节点的下线而无法正常工作

下面开始搭建redis集群

由于最小的redis集群需要3个主节点,一台机器可运行多个redis实例,我搭建时使用两台机器,6个redis实例,其中三个主节点,三个从节点作为备份
网上很多使用单台服务器开6个端口,操作差不多,只是配置基本相对简单点,多台服务器更接近生产环境

redis 6个节点的ip和端口对应关系
server1:
192.168.1.198:7000
192.168.1.198:7001
192.168.1.198:7002
server2:
192.168.1.199:7003
192.168.1.199:7004
192.168.1.199:7005

1、安装需要的依赖包

[root@localhost ~]# yum install gcc gcc-c++ kernel-devel automake autoconf libtool make wget tcl vim ruby rubygems unzip git -y

2、两台机器分别下载redis并安装

[root@localhost src]# cd /usr/local/
[root@localhost local]# wget http://download.redis.io/releases/redis-3.0.6.tar.gz
[root@localhost local]# tar xzf redis-3.0.6.tar.gz
[root@localhost local]# cd redis-3.0.6
[root@localhost redis-3.0.6]# make

3、创建集群需要的目录

server1执行:

mkdir -p /usr/local/cluster
cd /usr/local/cluster
mkdir 7000
mkdir 7001
mkdir 7002server2执行:

mkdir -p /usr/local/cluster
cd /usr/local/cluster
mkdir 7003
mkdir 7004
mkdir 7005
4、修改配置文件redis.conf
cp /usr/local/redis-3.0.6/redis.conf  /usr/local/cluster
cd /usr/local/cluster
vi redis.conf

##注意每个实例的端口号不同
port 7000
daemonize yes
cluster-enabled yes
cluster-config-file nodes.conf
cluster-node-timeout 5000
appendonly yes##修改完redis.conf配置文件中的这些配置项之后把这个配置文件分别拷贝到7000/7001/7002/7003/7004/7005节点目录下
server1执行:

cp /usr/local/cluster/redis.conf /usr/local/cluster/7000
cp /usr/local/cluster/redis.conf /usr/local/cluster/7001
cp /usr/local/cluster/redis.conf /usr/local/cluster/7002server2执行:

cp /usr/local/cluster/redis.conf /usr/local/cluster/7003
cp /usr/local/cluster/redis.conf /usr/local/cluster/7004
cp /usr/local/cluster/redis.conf /usr/local/cluster/7005##注意:拷贝完成之后要分别修改7001/7002/7003/7004/7005目录下面redis.conf文件中的port参数,分别改为对应的文件夹的名称

5、分别启动这6个redis实例,并查看是否成功:ps -ef|grep redis
server1执行:

[root@localhost cluster]# cd /usr/local/cluster/7000
[root@localhost 7000]# redis-server redis.conf
[root@localhost 7000]# cd /usr/local/cluster/7001
[root@localhost 7001]# redis-server redis.conf
[root@localhost 7001]# cd /usr/local/cluster/7002
[root@localhost 7002]# redis-server redis.conf
[root@localhost 7002]# ps -ef|grep redis
root      2741    1  0 09:39 ?        00:00:00 redis-server *:7000 [cluster]
root      2747    1  0 09:40 ?        00:00:00 redis-server *:7001 [cluster]
root      2751    1  0 09:40 ?        00:00:00 redis-server *:7002 [cluster]
root      2755  2687  0 09:40 pts/0    00:00:00 grep redisserver2执行:
[root@localhost cluster]# cd /usr/local/cluster/7003
[root@localhost 7003]# redis-server redis.conf
[root@localhost 7003]# cd /usr/local/cluster/7004
[root@localhost 7004]# redis-server redis.conf
[root@localhost 7004]# cd /usr/local/cluster/7005
[root@localhost 7005]# redis-server redis.conf
[root@localhost 7005]# ps -ef|grep redis
root      1619    1  0 09:40 ?        00:00:00 redis-server *:7003 [cluster]
root      1623    1  0 09:40 ?        00:00:00 redis-server *:7004 [cluster]
root      1627    1  0 09:41 ?        00:00:00 redis-server *:7005 [cluster]
root      1631  1563  0 09:41 pts/0    00:00:00 grep redis

6、执行redis的创建集群命令创建集群(注意ip地址和端口号)

[root@localhost cluster]# cd /usr/local/redis-3.0.6/src
[root@localhost src]# ./redis-trib.rb  create --replicas 1 192.168.1.198:7000 192.168.1.198:7001 192.168.1.198:7002 192.168.1.199:7003 192.168.1.199:7004 192.168.1.199:70056.1到这一步因为前面第1步装了依赖包,未提示ruby和rubygems的错误,但还是会报错,提示不能加载redis,是因为缺少redis和ruby的接口,使用gem 安装
错误内容:
/usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `gem_original_require': no such file to load -- redis (LoadError)
        from /usr/lib/ruby/site_ruby/1.8/rubygems/custom_require.rb:31:in `require'
        from ./redis-trib.rb:25
解决:gem install redis
6.2 再次执行第6步的命令,正常执行,提示是否允许修改配置文件,输入yes,然后整个集群配置完成!
[root@localhost src]# ./redis-trib.rb  create --replicas 1 192.168.1.198:7000 192.168.1.198:7001 192.168.1.198:7002 192.168.1.199:7003 192.168.1.199:7004 192.168.1.199:7005
>>> Creating cluster
>>> Performing hash slots allocation on 6 nodes...
Using 3 masters:
192.168.1.199:7003
192.168.1.198:7000
192.168.1.199:7004
Adding replica 192.168.1.198:7001 to 192.168.1.199:7003
Adding replica 192.168.1.199:7005 to 192.168.1.198:7000
Adding replica 192.168.1.198:7002 to 192.168.1.199:7004
M: 2f70e9f2b4a06a846e46d7034a54e0fe6971beea 192.168.1.198:7000
  slots:5461-10922 (5462 slots) master
S: e60f49920cf8620927b200b0001892d08067d065 192.168.1.198:7001
  replicates 02f1958bd5032caca2fd47a56362c8d562d7e621
S: 26101db06b5c2d4431ca8308cf43d51f6939b4fc 192.168.1.198:7002
  replicates 6c4f18b9e8729c3ab5d43b00b0bc1e2ee976f299
M: 02f1958bd5032caca2fd47a56362c8d562d7e621 192.168.1.199:7003
  slots:0-5460 (5461 slots) master
M: 6c4f18b9e8729c3ab5d43b00b0bc1e2ee976f299 192.168.1.199:7004
  slots:10923-16383 (5461 slots) master
S: ebb27bd0a48b67a4f4e0584be27c1c909944e935 192.168.1.199:7005
  replicates 2f70e9f2b4a06a846e46d7034a54e0fe6971beea
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 192.168.1.198:7000)
M: 2f70e9f2b4a06a846e46d7034a54e0fe6971beea 192.168.1.198:7000
  slots:5461-10922 (5462 slots) master
M: e60f49920cf8620927b200b0001892d08067d065 192.168.1.198:7001
  slots: (0 slots) master
  replicates 02f1958bd5032caca2fd47a56362c8d562d7e621
M: 26101db06b5c2d4431ca8308cf43d51f6939b4fc 192.168.1.198:7002
  slots: (0 slots) master
  replicates 6c4f18b9e8729c3ab5d43b00b0bc1e2ee976f299
M: 02f1958bd5032caca2fd47a56362c8d562d7e621 192.168.1.199:7003
  slots:0-5460 (5461 slots) master
M: 6c4f18b9e8729c3ab5d43b00b0bc1e2ee976f299 192.168.1.199:7004
  slots:10923-16383 (5461 slots) master
M: ebb27bd0a48b67a4f4e0584be27c1c909944e935 192.168.1.199:7005
  slots: (0 slots) master
  replicates 2f70e9f2b4a06a846e46d7034a54e0fe6971beea
[OK] All nodes agree about slots configuration.
>>> Check for open slots...
>>> Check slots coverage...
[OK] All 16384 slots covered.

7、测试集群

server1上登录redis客户端并执行

[root@localhost src]# redis-cli -c -p 7000
127.0.0.1:7000> get key
-> Redirected to slot [12539] located at 192.168.1.199:7004
"val"
192.168.1.199:7004> set name test
-> Redirected to slot [5798] located at 192.168.1.198:7000
OK
192.168.1.198:7000> set adress shanghai
-> Redirected to slot [1562] located at 192.168.1.199:7003
OK
192.168.1.199:7003>server2上登录redis客户端并执行

[root@localhost src]# redis-cli -c -p 7003
127.0.0.1:7003> set key val
-> Redirected to slot [12539] located at 192.168.1.199:7004
OK
192.168.1.199:7004> get keyv
"val"
192.168.1.199:7004> set key2 val2
-> Redirected to slot [4998] located at 192.168.1.199:7003
OK
192.168.1.199:7003> get key2
"val2"
192.168.1.199:7003>

从中可以发现存时是分布式存储,取时也是从集群中取,测试成功

8、redis cluster 架构

1)redis-cluster架构图

CentOS完美搭建Redis3.0集群并附测试-LMLPHP

架构细节:

(1)所有的redis节点彼此互联(PING-PONG机制),内部使用二进制协议优化传输速度和带宽.

(2)节点的fail是通过集群中超过半数的节点检测失效时才生效.

(3)客户端与redis节点直连,不需要中间proxy层.客户端不需要连接集群所有节点,连接集群中任何一个可用节点即可

(4)redis-cluster把所有的物理节点映射到[0-16383]slot上,cluster 负责维护node<->slot<->value

2) redis-cluster选举:容错

CentOS完美搭建Redis3.0集群并附测试-LMLPHP

(1)领着选举过程是集群中所有master参与,如果半数以上master节点与master节点通信超过(cluster-node-timeout),认为当前master节点挂掉.

(2):什么时候整个集群不可用(cluster_state:fail),当集群不可用时,所有对集群的操作做都不可用,收到((error) CLUSTERDOWN The cluster is down)错误

a:如果集群任意master挂掉,且当前master没有slave.集群进入fail状态,也可以理解成进群的slot映射[0-16383]不完成时进入fail状态.

b:如果进群超过半数以上master挂掉,无论是否有slave集群进入fail状态.

下面关于Redis的文章您也可能喜欢,不妨参考下:

Ubuntu 14.04下Redis安装及简单测试 http://www.linuxidc.com/Linux/2014-05/101544.htm

Redis主从复制基本配置 http://www.linuxidc.com/Linux/2015-03/115610.htm

Redis集群明细文档 http://www.linuxidc.com/Linux/2013-09/90118.htm

Ubuntu 12.10下安装Redis(图文详解)+ Jedis连接Redis http://www.linuxidc.com/Linux/2013-06/85816.htm

Redis系列-安装部署维护篇 http://www.linuxidc.com/Linux/2012-12/75627.htm

CentOS 6.3安装Redis http://www.linuxidc.com/Linux/2012-12/75314.htm

Redis安装部署学习笔记 http://www.linuxidc.com/Linux/2014-07/104306.htm

Redis配置文件redis.conf 详解 http://www.linuxidc.com/Linux/2013-11/92524.htm

Redis 的详细介绍请点这里 
Redis 的下载地址请点这里

05-04 07:33