redis+keepalived实现高可用

lukiuy

Redis简介：

Redis是一个开源的使用ANSI C语言编写、支持网络、可基于内存亦可持久化的日志型、Key-Value数据库，并提供多种语言的API。从2010年3月15日起，Redis的开发工作由VMware主持。

redis是一个key-value存储系统。和Memcached类似，它支持存储的value类型相对更多，包括string(字符串)、list(链表)、set(集合)、zset(sorted set –有序集合)和hash（哈希类型）。这些数据类型都支持push/pop、add/remove及取交集并集和差集及更丰富的操作，而且这些操作都是原子性的。在此基础上，redis支持各种不同方式的排序。与memcached一样，为了保证效率，数据都是缓存在内存中。区别的是redis会周期性的把更新的数据写入磁盘或者把修改操作写入追加的记录文件，并且在此基础上实现了master-slave(主从)同步。

设计思路：
redis 主和 redis从  正常同步；

redis主keepalived 启动，执行redis_master.sh脚本，vip在自己身上；

redis 从keepalived 启动，执行redis_slave.sh脚本；

redis主服务关闭，则redis主执行redis_fault.sh脚本， vip落在redis 从上，redis从执行redis_master.sh脚本，变成主；

redis主服务开启，则redis主执行redis_slave.sh脚本变成从，vip还在redis 从上，还是主；

redis从服务关闭，则redis从执行redis_fault.sh脚本， vip落在redis主上，redis主执行redis_master.sh脚本，变成主；

redis从服务开启，则redis从执行redis_slave.sh脚本变成从， vip还在redis主上，redis主继续做主，此时为redis初试主从状态；

环境：

192.168.1.100 redis

192.168.1.101 redis-slave

192.168.1.111 VIP

一、安装keepalived

(redis和redis-slave两台服务器都安装)

yum install ipvsadm -y

yum install gcc kernel-devel openssl-devel popt-devel libnl-devel -y

tar xf keepalived-1.2.7.tar.gz

cd keepalived-1.2.7

./configure --prefix=/ --with-kernel-

dir=/usr/src/kernels/2.6.32-279.el6.i686/&&make&&make install

chkconfig --add keepalive

chkconfig --add keepalived

chkconfig keepalived on

二、安装redis

(redis和redis-slave两台服务器都安装)

wget http://download.redis.io/releases/redis-2.8.13.tar.gz

tar xf redis-2.8.13.tar.gz

cd redis-2.8.13

make

make install

cd src && make test

错误解决：

wget http://downloads.sourceforge.net/tcl/tcl8.6.4-src.tar.gz

mv tcl8.6.4-src.tar.gz /opt/

cd /opt/

tar xf tcl8.6.4-src.tar.gz

cd tcl8.6.4

cd unix/

./configure

make&&make install

cd redis-2.8.13

make test

redis-slve只需注意一点

[iyunv@redis bin]# pwd

/usr/local/bin

[iyunv@redis bin]# vim redis.conf

116  slaveof 192.168.1.100 6379

三、通过Keepalived实现Redis Failover自动故障切换

修改Master和Slave的/etc/hosts文件

[iyunv@redis rc.d]# cat /etc/hosts

192.168.1.100  redis

192.168.1.101   redis-slave

Master上是

[iyunv@redis rc.d]# cat /etc/sysconfig/network

NETWORKING=yes

HOSTNAME=redis

Slave上是

[iyunv@redis-slave linux]# cat /etc/sysconfig/network

NETWORKING=yes

HOSTNAME=redis-slave

修改完主机名重启机器生效

默认安装完成keepalived之后是没有配置文件的，因此我们需要手动创建：

首先，在Master上创建如下配置文件：

[iyunv@redis  linux]# vim /etc/keepalived/keepalived.conf

global_defs {

   notification_email {

     Yy520it@163.com

   }

   notification_email_from keepalived@redis

   router_id redis

}

vrrp_script chk_redis {

    script "/etc/keepalived/scripts/redis_check.sh"

    interval 1

}

vrrp_instance mes_Redis {

    state MASTER

    interface eth0

    garp_master_delay 10

    smtp_alert

    virtual_router_id 3

    priority 100

    nopreempt

    advert_int 1

    authentication {

        auth_type PASS

        auth_pass 1111

    }

    virtual_ipaddress {

        192.168.1.111

    }

    track_script {

        chk_redis

    }

    notify_master /etc/keepalived/scripts/redis_master.sh

    notify_backup /etc/keepalived/scripts/redis_slave.sh

    notify_fault  /etc/keepalived/scripts/redis_fault.sh

    notify_stop   /etc/keepalived/scripts/redis_stop.sh

}

然后，在Slave上创建如下配置文件：

[iyunv@redis-slave linux]# vim /etc/keepalived/keepalived.conf

global_defs {

   notification_email {

     Yy520it@163.com

   }

   notification_email_from keepalived@redis-slave

   router_id redis-salve

}

vrrp_script chk_redis {

    script "/etc/keepalived/scripts/redis_check.sh"

    interval 1

}

vrrp_instance mes_Redis {

    state BACKUP

    interface eth0

    garp_master_delay 10

    smtp_alert

    virtual_router_id 3

    priority 90

    nopreempt

    advert_int 1

    authentication {

        auth_type PASS

        auth_pass 1111

    }

    virtual_ipaddress {

        192.168.1.111

    }

    track_script {

        chk_redis

    }

    notify_master /etc/keepalived/scripts/redis_master.sh

    notify_backup /etc/keepalived/scripts/redis_slave.sh

    notify_fault  /etc/keepalived/scripts/redis_fault.sh

    notify_stop   /etc/keepalived/scripts/redis_stop.sh

}

在Master和Slave上创建监控Redis的脚本

mkdir /etc/keepalived/scripts

vim /etc/keepalived/scripts/redis_check.sh

#!/bin/bash

ALIVE=`/usr/local/bin/redis-cli PING`

if [ "$ALIVE" == "PONG" ]; then

  echo $ALIVE

  exit 0

else

  echo $ALIVE

  exit 1

fi

编写以下负责运作的关键脚本：

notify_master /etc/keepalived/scripts/redis_master.sh

notify_backup /etc/keepalived/scripts/redis_slave.sh

notify_fault /etc/keepalived/scripts/redis_fault.sh

notify_stop /etc/keepalived/scripts/redis_stop.sh

因为Keepalived在转换状态时会依照状态来呼叫：

当进入Master状态时会呼叫notify_master

当进入Backup状态时会呼叫notify_backup

当发现异常情况时进入Fault状态呼叫notify_fault

当Keepalived程序终止时则呼叫notify_stop

首先，在Redis Master上创建notity_master与notify_backup脚本：

vim /etc/keepalived/scripts/redis_master.sh

#!/bin/bash

REDISCLI="/usr/local/bin/redis-cli"

LOGFILE="/var/log/keepalived-redis-state.log"

echo "[master]" >> $LOGFILE

date >> $LOGFILE

echo "Being master...." >> $LOGFILE 2>&1

echo "Run SLAVEOF cmd ..." >> $LOGFILE

$REDISCLI SLAVEOF 192.168.1.101 6379 >> $LOGFILE  2>&1

sleep 10 #延迟10秒以后待数据同步完成后再取消同步状态

echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE

$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1

vim /etc/keepalived/scripts/redis_slave.sh

#!/bin/bash

REDISCLI="/usr/local/bin/redis-cli"

LOGFILE="/var/log/keepalived-redis-state.log"

echo "[backup]" >> $LOGFILE

date >> $LOGFILE

echo "Being slave...." >> $LOGFILE 2>&1

sleep 15 #延迟15秒待数据被对方同步完成之后再切换主从角色

echo "Run SLAVEOF cmd ..." >> $LOGFILE

$REDISCLI SLAVEOF 192.168.1.101 6379 >> $LOGFILE  2>&1

接着，在Redis Slave上创建notity_master与notify_backup脚本：

vim /etc/keepalived/scripts/redis_master.sh

#!/bin/bash

REDISCLI="/usr/local/bin/redis-cli"

LOGFILE="/var/log/keepalived-redis-state.log"

echo "[master]" >> $LOGFILE

date >> $LOGFILE

echo "Being master...." >> $LOGFILE 2>&1

echo "Run SLAVEOF cmd ..." >> $LOGFILE

$REDISCLI SLAVEOF 192.168.1.100 6379 >> $LOGFILE  2>&1

sleep 10 #延迟10秒以后待数据同步完成后再取消同步状态

echo "Run SLAVEOF NO ONE cmd ..." >> $LOGFILE

$REDISCLI SLAVEOF NO ONE >> $LOGFILE 2>&1

vim /etc/keepalived/scripts/redis_slave.sh

#!/bin/bash

REDISCLI="/usr/local/bin/redis-cli"

LOGFILE="/var/log/keepalived-redis-state.log"

echo "[backup]" >> $LOGFILE

date >> $LOGFILE

echo "Being slave...." >> $LOGFILE 2>&1

sleep 15 #延迟15秒待数据被对方同步完成之后再切换主从角色

echo "Run SLAVEOF cmd ..." >> $LOGFILE

$REDISCLI SLAVEOF 192.168.1.100 6379 >> $LOGFILE  2>&1

然后在Master与Slave创建如下相同的脚本：

vim /etc/keepalived/scripts/redis_fault.sh

#!/bin/bash

LOGFILE=/var/log/keepalived-redis-state.log

echo "[fault]" >> $LOGFILE

date >> $LOGFILE

vim /etc/keepalived/scripts/redis_stop.sh

#!/bin/bash

LOGFILE=/var/log/keepalived-redis-state.log

echo "[stop]" >> $LOGFILE

date >> $LOGFILE

在Master与Slave给脚本都加上可执行权限：

chmod +x /etc/keepalived/scripts/*.sh

四、脚本创建完成以后，我们开始按照如下流程进行测试：

1.启动Master上的Redis

[iyunv@redis bin]# pwd

/usr/local/bin

[iyunv@redis bin]# ./redis-server redis.conf

2.启动Slave上的Redis

[iyunv@redis bin]# pwd

/usr/local/bin

[iyunv@redis bin]# ./redis-server redis.conf

3.启动Master上的Keepalived

/etc/init.d/keepalived start

4.启动Slave上的Keepalived

/etc/init.d/keepalived start

5.尝试通过VIP连接Redis:

[iyunv@redis bin]#pwd

/usr/local/bin

[iyunv@redis bin]# ./redis-cli -h 192.168.1.111 info

role:master

slave0:192.168.1.101,6379,online

连接成功，Slave也连接上来了

6.尝试插入一些数据：

[iyunv@redis bin]# ./redis-cli -h 192.168.1.111 SET Hello Redis

从VIP读取数据

[iyunv@redis bin]# ./redis-cli -h 192.168.1.111 GET Hello

"Redis"

从Master读取数据

[iyunv@redis bin]# ./redis-cli -h 192.168.100  GET Hello

"Redis"

从Slave读取数据

[iyunv@redis-slave bin]# ./redis-cli -h 192.168.1.100  GET Hello

"Redis"

下面，模拟故障产生：

将Master上的Redis进程杀死：

[iyunv@redis bin]# ./redis-cli shutdown

查看Master上的Keepalived日志

[iyunv@redis scripts]# tail /var/log/keepalived-redis-state.log

[fault]

Thu Sep 27 08:29:01 CST 2012

同时Slave上的日志显示：

[iyunv@redis-slave scripts]# tail /var/log/keepalived-redis-state.log

[master]

Thu Nov 15 12:06:04 CST 2012

Being master....

Run SLAVEOF cmd ...

OK

Run SLAVEOF NO ONE cmd ...

OK

然后我们可以发现，Slave已经接管服务，并且担任Master的角色了。

./redis-cli -h 192.168.1.111 info

./redis-cli -h 192.168.1.101 info

role:master

然后我们恢复Master的Redis进程

主变成slave

然后把101redis停掉

100恢复主的角色，在把101redis开启

恢复100是主，101是备

自动切换成功！

五、Redis 常用命令之服务器相关命令

redis-cli -h 192.168.12.12    远程登录redis客户端

redis 127.0.0.1:6379> ping   测试连接是否存活  

PONG

redis 127.0.0.1:6379> echo wilian 在命令行打印一些内容

"wilian"

redis 127.0.0.1:6379> select 1 选择数据库。Redis数据库编号从0~15，我们可以选择任意一个数据库来进行数据的存取

OK

redis 127.0.0.1:6379[1]> dbsize  返回当前数据库中key的数目。

(integer) 0

redis 127.0.0.1:6379[1]> select 0

OK

redis 127.0.0.1:6379> dbsize

(integer) 20

redis 127.0.0.1:6379> info 获取服务器的信息和统计

redis_version:2.4.5

redis_git_sha1:00000000

redis_git_dirty:0

arch_bits:32

multiplexing_api:winsock2

process_id:5956

uptime_in_seconds:100358

uptime_in_days:1

lru_clock:1957468

used_cpu_sys:4.70

used_cpu_user:4.99

used_cpu_sys_children:0.00

used_cpu_user_children:0.00

connected_clients:1

connected_slaves:0

client_longest_output_list:0

client_biggest_input_buf:0

blocked_clients:0

used_memory:684452

used_memory_human:668.41K

used_memory_rss:684452

used_memory_peak:684424

used_memory_peak_human:668.38K

mem_fragmentation_ratio:1.00

mem_allocator:libc

loading:0

aof_enabled:0

changes_since_last_save:0

bgsave_in_progress:0

last_save_time:1340763023

bgrewriteaof_in_progress:0

total_connections_received:1

total_commands_processed:199

expired_keys:3

evicted_keys:0

keyspace_hits:163

keyspace_misses:35

pubsub_channels:0

pubsub_patterns:0

latest_fork_usec:0

vm_enabled:0

role:master

db0:keys=20,expires=0

redis 127.0.0.1:6379> monitor 实时转储收到的请求。

OK

1340780669.110663 "monitor"

redis 127.0.0.1:6379> config get dir 获取服务器配置信息

1) "dir"

2) "D:\\mysoft\\redis-2.0.2"

flushdb 删除当前选择数据库中的所有key

flushall  删除所有数据库中的所有key