linux 双Redis + keepalived 主从复制+宕机自主切换

主要核心思想，如果master 和 salve 全部存活的情况，VIP就漂移到 master。读写都从master操作，如果master宕机，VIP就会漂移到salve,并将之前的salve切换为master,当宕机的master可以继续服务的时候，首先会从salve同步数据，然后VIP漂移到master服务器上面，持续提供服务。

环境准备：

　　master：ip 192.168.28.139；redis 19020；redis 19021；keepalived

　　slave ：ip 192.168.28.140；redis 19020；redis 19021；keepalived

　　keepalived VIP：192.168.28.99

1、下载Redis redis-5.0.5.tar.gz

解压 tar xzf + Redis包（重复一下操作，改名可以配置2个redis）

mv redis-5.0.5 /usr/local/redis19020

进入 Redis文件安装

安装依赖文件

yum install gcc-c++

安装

make

mv redis.conf redis.conf.back

重写conf文件

vim redis.conf

=======================================

daemonize yes

pidfile /var/run/redis19020.pid

#pidfile /var/run/redis19021.pid

port 19020       #19021

tcp-backlog 511

timeout 30

tcp-keepalive 60

loglevel warning

logfile /logs/redis/redis19020.log

#logfile /logs/redis/redis19021.log

databases 16

save 900 1

save 300 10

save 60 10000

stop-writes-on-bgsave-error yes

rdbcompression yes

rdbchecksum yes

dbfilename dump.rdb

dir /usr/local/redis-5.0.5/ #redis安装路径

protected-mode no　　#关闭保护模式

requirepass test123　　#主Redis 密码

#masterauth test123    #从Redis 密码（与主一致）

#slaveof 192.168.28.139 19021 #从Redis设置 Redis主从配置（主Redis ip 端口）

slave-serve-stale-data yes

slave-read-only yes

repl-diskless-sync no

repl-diskless-sync-delay 5

repl-disable-tcp-nodelay no

slave-priority 100

appendonly no

appendfilename "appendonly.aof"

appendfsync everysec

no-appendfsync-on-rewrite no

auto-aof-rewrite-percentage 100

auto-aof-rewrite-min-size 64mb

aof-load-truncated yes

lua-time-limit 5000

slowlog-log-slower-than 10000

slowlog-max-len 128

latency-monitor-threshold 0

notify-keyspace-events ""

hash-max-ziplist-entries 512

hash-max-ziplist-value 64

list-max-ziplist-entries 512

list-max-ziplist-value 64

set-max-intset-entries 512

zset-max-ziplist-entries 128

zset-max-ziplist-value 64

hll-sparse-max-bytes 3000

activerehashing yes

client-output-buffer-limit normal 0 0 0

client-output-buffer-limit slave 256mb 64mb 60

client-output-buffer-limit pubsub 32mb 8mb 60

hz 10

aof-rewrite-incremental-fsync yes

==============================================

mkdir /logs/redis

touch /logs/redis/{redis19020.log,redis19021.log}

启动redis服务，并指定启动服务配置文件

src/redis-server redis.conf

设置环境变量

将 Redis 添加到环境变量中： 

# vi /etc/profile 

在最后添加以下内容： 

## Redis env 

export PATH=$PATH:/usr/local/redis19020/src

export PATH=$PATH:/usr/local/redis19021/src

使配置生效： 

# source /etc/profile 

现在就可以直接使用 redis-cli 等 redis 命令了。

2、keepalived安装

下载keepalived

官网: https://keepalived.org/download.html

上传并解压keepalived

/home

cd /home/

tar -zxvf keepalived-2.0.18.tar.gz -C /usr/local/src/

进入目录/usr/local/src/keepalived-2.0.18

cd /usr/local/keepalived-2.0.18/

检查安装环境

./configure --prefix=/usr/local/keepalived

首次检查

configure: error:

  !!! OpenSSL is not properly installed on your system. !!!

  !!! Can not inclu

de OpenSSL headers files.            !!!

安装openssl openssl-devel解决问题

yum -y install openssl openssl-devel

二次检查

*** WARNING - this build will not support IPVS with IPv6. Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.

安装libnl libnl-devel解决问题

yum -y install libnl libnl-devel

其他问题

configure: error: libnfnetlink headers missing

安装libnfnetlink-devel解决问题

yum -y install libnfnetlink-devel

编译并安装

make && make install

将keepalived添加到系统服务中

拷贝执行文件

cp /usr/local/keepalived/sbin/keepalived /usr/sbin/

将init.d文件拷贝到etc下,加入开机启动项

cp /usr/local/src/keepalived-2.0.18/keepalived/etc/init.d/keepalived /etc/init.d/keepalived

将keepalived文件拷贝到etc下

cp /usr/local/src/keepalived-2.0.18/keepalived/etc/sysconfig/keepalived /etc/sysconfig/

创建keepalived文件夹

mkdir -p /etc/keepalived

将keepalived配置文件拷贝到etc下

cp /usr/local/src/keepalived-2.0.18/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf

添加keepalived到开机启动

chkconfig --add keepalived

添加可执行权限

chmod +x /etc/init.d/keepalived

二、部署keepalived双击自主切换（以下配置文件和脚本，两台机器都要重新布）

备份keepalived配置文件

cp keepalived.conf keepalived.conf.back

重新编辑配置文件

vim keepalived.conf

配置文件

================================================

! COnfiguration File for keepalived

global_defs {
router_id MASTER-HA　　#主机标识
#router_id BACKUP　　　#备机标识

script_user root
enable_script_security

}

vrrp_script chk_redis {
script "/etc/keepalived/scripts/redis_check.sh"   #脚本地址和名字，此处调用改脚本
interval 2
weight -5
fall 2
rise 1
}

vrrp_instance VI_1 {
state MASTER　　#主机MASTER、备机BACKUP
interface eth0　　#本机的网卡
virtual_router_id 51
priority 101           #主机101，备机小于101便可
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.28.99    #新的IP地址，需要在同机网段内
}

track_script {
chk_redis
}

notify_master /etc/keepalived/scripts/redis_master.sh
notify_backup /etc/keepalived/scripts/redis_backup.sh
notify_fault /etc/keepalived/scripts/redis_fault.sh
notify_stop /etc/keepalived/scripts/redis_stop.sh

}

================================================

新建文件夹scripts

mkdir scripts

新建脚本文件夹

touch {redis_check.sh,redis_master.sh,redis_backup.sh,redis_fault.sh,redis_stop.sh}

编写脚本

vim redis_check.sh（共用脚本）

主reids脚本

vim redis_master.sh

redis_backup.sh

从Redis脚本

vim redis_master.sh

redis_backup.sh

共用脚本

redis_fault.sh

redis_stop.sh

添加可执行权限

chmod +x /etc/init.d/keepalived

显示脚本文件为

启动keepalived

/etc/init.d/keepalived start

查看是否启动成功

ps -ef | grep keepalived

启动成功之后会生成一个新的服务器IP地址，可通过新IP直接连接Redis，可以自由关闭其中一台Redis服务，keepalived会自动切换到另外一台Redis服务器当中。

宕机后启动顺序为，先启动Redis，在启动keepalived即可，启动后会自动同步两台Redis的数据。