Session sharing: How PHP and Redis clusters implement session sharing

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One, Redis db cluster installation

1. Software version redis-3.2.11, php-redis-2.2.4

Role	IP Address	Host Name
Redis Database Server	192.168.1.41	Redis41
Slave 1 Redis Database server	192.168.1.42	Redis42
Slave 2 Redis Database server	192.168.1.43	Redis43
VIP Address	192.168.1.40

Three databases are also configured

Adduser-s/sbin/nologin-d/var/lib/redis redisyum-y install gcc gcc-c++tar-xf redis-3.2.11.tar.gzcd redis-3.2.11/make MALLOC=LIBC   //with malloc this environment variable to compile Redis, and libc is not the default allocator, the default is jemallocmake Prefix=/usr/local/redis install    // Specify the installation path mkdir-p/USR/LOCAL/REDIS/CONFCP redis.conf/usr/local/redis/conf/    CP sentinel.conf/usr/local/redis/conf/

Common configuration Options/usr/local/redis/conf/redis.conf

–port 6379     //Port –bind 192.168.1.41     //IP address –tcp-backlog 511//tcp     Connections Total –timeout 0     //Connection time-out –tcp-keepali ve     //Long connection time –daemonize Yes/     /daemon mode run –databases     //Database number –logfile/var/log/redis_6379.log     // PID file –maxclients 10000     //number of concurrent connections –dir/var/lib/redis/6379    //Database directory

Configure Redis to enable SYSTEMCLT System management (not required)

1. Vim/usr/lib/systemd/system/redis.server

[Unit] Description=redis in-memory Data storeafter=network.target[service]user=redisgroup=redistype=simpleexecstart=/usr /local/redis/bin/redis-server/usr/local/redis/conf/redis.confexecstop=/usr/local/redis/bin/redis-cli Shutdownrestart=alwaysrestartsec=42s[install]wantedby=multi-user.target

Second, install Php-redis extension

Configuring PHP to support Redis

Tar zxvf phpredis-2.2.4.tar.gz   cd phpredis-2.2.4    /usr/local/php/bin/phpize    //phpize configuration file is generated with the. Configure--enable-redis--with-php-config=/usr/local/php/bin/php-config make  && make install    php-m |grep Redis

Write a test File redis.php page test

<?php$redis = new Redis (); $redis->connect (' 192.168.1.41 ', 6379); $redis->set (' redistest ', ' 666666 '); echo $ Redis->get (' redistest ');? >

Third, Redis server cluster is highly available

the Redis cluster implementation is probably in the following ways :

Redis-cluster, the  official provision of the cluster construction scheme (too heavy, more suitable for later data when the use of a large amount of time) redis+keepalive  virtual IP, multiple configurations are very complex, not suitable for maintenance, need slaveof no one Script Redis+zookeeper  need to introduce zookeeper, to the existing code changes Redis+sentinel   Redis self-monitoring middleware, Sentinel mode configuration three Redis server configuration master-slave relationship, in the slave Add configuration slaveof 192.168.1.41 6379 view cluster master-slave relationship redis-cli-h 192.168.1.41-p 6379 Info replication

Modify Redis Sentinel Profile sentinel.conf

Bind 192.168.1.41protected-mode nodaemonize yesport 26379dir/tmpsentinel monitor MyMaster 192.168.1.41 6379 2sentinel do Wn-after-milliseconds mymaster 3000sentinel parallel-syncs mymaster 1sentinel failover-timeout mymaster 5000sentinel Client-reconfig-script mymaster/usr/local/redis/conf/reconfig.sh in the main, starting from the Sentinelredis-sentinel/usr/local/redis /conf/sentinel.conf View Sentinel Status redis-cli-h 192.168.1.41-p 26379 info Sentinel

Iv. Client compatibility issues

Client programs (such as PHP programs) require IP and port to connect to Redis, but when Redis-server fails over, the primary database is changed, so the IP address is also variable, how does the client program perceive the current master Redis IP address and port?
Redis-sentinel provides an interface to request any Sentinel, send Sentinel Get-master-addr-by-name <master name> to get the current master Redis IP and port.

Solution:

Add configuration switch Script sentinel.conf, when the primary database service goes down, the VIP drift is automatically switched to master and slave.
Sentinel Client-reconfig-script mymaster/usr/local/redis/conf/reconfig.sh

#!/bin/bash#mymaster leader start 192.168.1.41 6379 192.168.1.42 6379vip= "192.168.1.40/24" local_ip=$ (IP  addr Show Dev eth0 |awk ' $1== "inet" {print $} ') if [["${local_ip%%/*}" = = "$4"]];then   /usr/sbin/ifconfig eth0:1 downelif [["${ local_ip%%/*} "= =" $6 "]];then   /usr/sbin/ifconfig eth0:1" ${vip} "fi