Redis+Keepalived高可用环境部署记录 – 散尽浮华 – 博客园

https://www.cnblogs.com/kevingrace/p/9001975.html

Keepalived 实现VRRP（虚拟路由冗余）协议，从路由级别实现VIP切换，可以完全避免类似heartbeat脑裂问题，可以很好的实现主从、主备、互备方案，尤其是无状态业务，有状态业务就需要额外花些功夫了。既然Mysql可以使用Keepalived很好的做到主从切换，那么Redis自然可以使用这种方式实现高可用。

Redis主从实现完全没有Mysql成熟，仅仅是可用而已，经过测试主从也不是那么完全不靠谱，主要问题在于同步连接断开之后需要重新全量同步，如果频繁进行会对主服务带来很大性能影响。但现实中主从机器往往要求放在一个机柜同一台交换设备下，网络闪断情况极低；再者主从同步在同步数量量大情况下，需要将缓存区调得足够大，不然也容易造成连接断开。
实现切换逻辑如下：A和B两台机器
1）A 、B机器依次启动，A机作为主、B机为从。
2）主A机挂掉，B机接管业务并作为主。
3）A机起来，作为从SLAVEOF B。
4）B机挂掉，A机再切回主。

在Keepalived 有两个角色：Master(一个)、Backup（多个），如果设置一个为Master，但Master挂了后再起来，必然再次业务又一次切换，这对于有状态服务是不可接受的。解决方案就是两台机器都设置为Backup，而且优先级高的Backup设置为nopreemt 不抢占。

部署记录：

0）服务器信息

192.168.10.205 redis-master 需要安装redis(3.2.0版本)、keepalived(1.3.2版本)

192.168.10.206 redis-slave 需要安装redis(3.2.0版本)、keepalived(1.3.2版本)

192.168.10.230 VIP

关闭两个节点机器的iptables和selinux（两个节点上都要操作）

[root@redis-master ~]

......

SELINUX=disabled

[root@redis-master ~]

Permissive

1）安装redis服务及主从配置（两个节点机都要操作）

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[root@redis-master ~]

[root@redis-master src]

[root@redis-master redis-3.2.0]

添加相关文件及命令

[root@redis-master redis-3.2.0]

[root@redis-master src]

[root@redis-master redis-3.2.0]

添加redis启动脚本

[root@redis-master redis-3.2.0]

#!/bin/bash

REDISPORT=6379

EXEC=/usr/local/redis/bin/redis-server

REDIS_CLI=/usr/local/redis/bin/redis-cli

PIDFILE=/var/run/redis.pid

CONF="/etc/redis.conf"

case "$1" in

start)

if [ -f $PIDFILE ]

then

echo "$PIDFILE exists, process is already running or crashed"

else

echo "Starting Redis server..."

$EXEC $CONF

fi

if [ "$?"="0" ]

then

echo "Redis is running..."

fi

;;

stop)

if [ ! -f $PIDFILE ]

then

echo "$PIDFILE does not exist, process is not running"

else

PID=$(cat $PIDFILE)

echo "Stopping ..."

$REDIS_CLI -p $REDISPORT SHUTDOWN

while [ -x ${PIDFILE} ]

do

echo "Waiting for Redis to shutdown ..."

sleep 1

done

echo "Redis stopped"

fi

;;

restart|force-reload)

${0} stop

${0} start

;;

*)

echo "Usage: /etc/init.d/redis {start|stop|restart|force-reload}" >&2

exit 1

esac

添加执行权限

[root@redis-master redis-3.2.0]

设置开机自启动

[root@redis-master redis-3.2.0]

创建redis状态日志

[root@redis-master redis-3.2.0]

redis主从配置（先看下redis-master主节点的配置）

[root@redis-master redis-3.2.0]

.......

port 6379

.......

daemonize yes

.......

bind 0.0.0.0

.......

pidfile /var/run/redis.pid

.......

logfile /var/log/redis/redis.log

.......

dir /var/redis/redis

.......

appendonly yes

appendfilename "appendonly.aof"

appendfsync everysec

.....

save 900 1

save 300 10

save 60 10000 ＃即在多少秒的时间内，有多少key被改变的数据添加到.rdb文件里

.......

slave-serve-stale-data yes

slave-read-only yes

......

dbfilename dump.rdb ＃快照文件名称

......

另一个从节点redis-slave的redis.conf配置和上面基本差不多，只是多了下面一行配置：

slaveof 192.168.10.205 6379

接着创建redis的数据目录

[root@redis-master redis-3.2.0]

然后启动两个节点的redis服务

[root@redis-master redis-3.2.0]

Starting Redis server...

Redis is running...

[root@redis-master redis-3.2.0]

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

redis-ser 17265 root 4u IPv4 59068 0t0 TCP *:6379 (LISTEN)

2）Keepalived安装（两个节点机都要操作）

redis主从配置简单说明

redis的主从复制实现简单却功能强大，其具有以下特点：

1）一个master支持多个slave连接，slave可以接受其他slave的连接

2）主从同步时，master和slave都是非阻塞的

redis主从复制可以用来：

1）data redundancy（数据冗余）

2）slave作为master的扩展，提供一些read-only的服务

3）可以将数据持久化放在slave做，从而提升master性能

通过简单的配置slave（master端无需配置），用户就能使用redis的主从复制，即只需在slave端的redis.conf文件中配置下面一行：

slaveof <masterip> <masterport>

表示该redis服务作为slave，masterip和masterport分别为master 的ip和port

其他配置：

masterauth <master-password>

如果master设置了安全密码，则此处设置为相应的密码

slave-serve-stale-data yes 当slave丢失master或者同步正在进行时，如果发生对slave的服务请求：

slave-serve-stale-data设置为yes则slave依然正常提供服务

slave-serve-stale-data设置为no则slave返回client错误："SYNC with master in progress"

repl-ping-slave-period 10

slave发送PINGS到master的时间间隔

repl-timeout 60

IO超时时间

3）redis+keepalived配置

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a）先进行redis-master主节点的高可用配置

[root@redis-master ~]

! Configuration File for keepalived

global_defs {

router_id redis-master

}

vrrp_script chk_redis {

script "/usr/local/keepalived/scripts/redis_check.sh 127.0.0.1 6379"

interval 2

timeout 2

fall 3

}

vrrp_instance redis {

state BACKUP

interface eth0

lvs_sync_daemon_interface eth0

virtual_router_id 202

priority 150

nopreempt

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

192.168.10.230

}

track_script {

chk_redis

}

notify_master "/usr/local/keepalived/scripts/redis_master.sh 127.0.0.1 192.168.10.206 6379"

notify_backup "/usr/local/keepalived/scripts/redis_backup.sh 127.0.0.1 192.168.10.206 6379"

notify_fault /usr/local/keepalived/scripts/redis_fault.sh

notify_stop /usr/local/keepalived/scripts/redis_stop.sh

}

b）接着进行redis-slave从节点的高可用配置

[root@redis-slave ~]

! Configuration File for keepalived

global_defs {

router_id redis-slave

}

vrrp_script chk_redis{

script "/usr/local/keepalived/scripts/redis_check.sh 127.0.0.1 6379"

interval 2

timeout 2

fall 3

}

vrrp_instance redis {

state BACKUP

interface eth0

lvs_sync_daemon_interface eth0

virtual_router_id 202

priority 100

nopreempt

advert_int 1

authentication {

auth_type PASS

auth_pass 1111

}

virtual_ipaddress {

192.168.10.230

}

track_script {

chk_redis

}

notify_master "/usr/local/keepalived/scripts/redis_master.sh 127.0.0.1 192.168.10.205 6379"

notify_backup "/usr/local/keepalived/scripts/redis_backup.sh 127.0.0.1 192.168.10.205 6379"

notify_fault /usr/local/keepalived/scripts/redis_fault.sh

notify_stop /usr/local/keepalived/scripts/redis_stop.sh

}

c）在redis-master和redis-slave两个节点机器上都要创建监控脚本（下面几个脚本，在两个节点上都要同样配置）

首先配置监控脚本

[root@redis-master ~]

#!/bin/bash

ALIVE=`/usr/local/redis/bin/redis-cli -h $1 -p $2 PING`

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

echo "[CHECK]" >> $LOGFILE

date >> $LOGFILE

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

echo "Success: redis-cli -h $1 -p $2 PING $ALIVE" >> $LOGFILE 2>&1

exit 0

else

echo "Failed:redis-cli -h $1 -p $2 PING $ALIVE " >> $LOGFILE 2>&1

exit 1

fi

需要注意的是：

以下负责运作的关键脚本：

notify_master /usr/local/keepalived/scripts/redis_master.sh

notify_backup /usr/local/keepalived/scripts/redis_backup.sh

notify_fault /usr/local/keepalived/scripts/redis_fault.sh

notify_stop /usr/local/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

温馨提示：
以上的keepalived.conf文件中的切换模式设置为nopreempt，意思是：
不抢占VIP资源，此种模式要是所有的节点都必须设置为state BACKUP模式！
需要注意无论主备服务器都需要设置为BACKUP，与以往KeepAlived的配置不同，其目的就是防止主服务器恢复后重新抢回VIP，导致Redis切换从而影响稳定。

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接着在redis-master主节点上创建notity_master与notify_backup脚本：

[root@redis-master ~]

#!/bin/bash

REDISCLI="/usr/local/redis/bin/redis-cli -h $1 -p $3"

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 $2 $3 >> $LOGFILE 2>&1

sleep 10

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

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

[root@redis-master ~]

#!/bin/bash

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

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

echo "[BACKUP]" >> $LOGFILE

date >> $LOGFILE

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

echo "Run SLAVEOF cmd ..." >> $LOGFILE 2>&1

$REDISCLI SLAVEOF $2 $3 >> $LOGFILE

sleep 100

exit(0)

[root@redis-master ~]

#!/bin/bash

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

echo "[fault]" >> $LOGFILE

date >> $LOGFILE

[root@redis-master ~]

#!/bin/bash

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

echo "[stop]" >> $LOGFILE

date >> $LOGFILE

[root@redis-master ~]

total 20

-rwxr-xr-x. 1 root root 283 May 7 07:20 redis_backup.sh

-rwxr-xr-x. 1 root root 360 May 7 07:12 redis_check.sh

-rwxr-xr-x. 1 root root 102 May 7 07:22 redis_fault.sh

-rwxr-xr-x. 1 root root 445 May 7 07:16 redis_master.sh

-rwxr-xr-x. 1 root root 101 May 7 07:23 redis_stop.sh

将redis-master主节点上的上面5个脚本直接复制到redis-slave节点上即可。

[root@redis-master ~]

到redis-slave从节点上查看脚本：

[root@redis-slave ~]

total 20

-rwxr-xr-x. 1 root root 283 May 7 07:20 redis_backup.sh

-rwxr-xr-x. 1 root root 360 May 7 07:12 redis_check.sh

-rwxr-xr-x. 1 root root 102 May 7 07:22 redis_fault.sh

-rwxr-xr-x. 1 root root 445 May 7 07:16 redis_master.sh

-rwxr-xr-x. 1 root root 101 May 7 07:23 redis_stop.sh

d）设置环境变量（两个节点上都要设置）

[root@redis-master ~]

......

export PATH=$PATH:/usr/local/redis/bin

[root@redis-master ~]

e）启动两个节点上的keepalived服务

[root@redis-master ~]

Starting keepalived: [ OK ]

[root@redis-master ~]

root 32509 1 0 07:29 ? 00:00:00 keepalived -D

root 32510 32509 0 07:29 ? 00:00:00 keepalived -D

root 32512 32509 0 07:29 ? 00:00:00 keepalived -D

root 32515 32512 0 07:29 ? 00:00:00 keepalived -D

root 32517 32515 0 07:29 ? 00:00:00 /bin/bash /usr/local/keepalived/scripts/redis_backup.sh 127.0.0.1 192.168.10.206 6379

root 32529 14122 0 07:29 pts/1 00:00:00 grep keepalived

[root@redis-slave ~]

Starting keepalived: [ OK ]

[root@redis-slave ~]

root 22277 1 0 07:29 ? 00:00:00 keepalived -D

root 22278 22277 0 07:29 ? 00:00:00 keepalived -D

root 22279 22277 0 07:29 ? 00:00:00 keepalived -D

root 22283 22279 0 07:29 ? 00:00:00 keepalived -D

root 22284 22283 0 07:29 ? 00:00:00 /bin/bash /usr/local/keepalived/scripts/redis_backup.sh 127.0.0.1 192.168.10.205 6379

root 22289 10868 0 07:29 pts/1 00:00:00 grep keepalived

查看下redis-master主节点，发现vip资源已经有了

[root@redis-master ~]

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

inet6 ::1/128 scope host

valid_lft forever preferred_lft forever

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

link/ether 52:54:00:b1:9c:93 brd ff:ff:ff:ff:ff:ff

inet 192.168.10.205/24 brd 192.168.10.255 scope global eth0

inet 192.168.10.230/32 scope global eth0

inet6 fe80::5054:ff:feb1:9c93/64 scope link

valid_lft forever preferred_lft forever

4）redis+keepalived主从高可用故障切换测试

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a）分别启动redis-mastr和redis-slave两个节点的redis和keepalived服务（如上已启动）

b）尝试通过VIP连接Redis:

[root@redis-master ~]

role:master

[root@redis-master ~]

role:master

[root@redis-master ~]

role:slave

连接成功，Slave也连接上来了。

c）尝试插入一些数据：

[root@redis-master ~]

OK

从VIP读取数据

[root@redis-master ~]

"Redis"

从redis-master主节点读取数据

[root@redis-master ~]

"Redis"

从redis-slave从节点读取数据

[root@redis-master ~]

"Redis"

e）然后开始模拟故障产生：

将redis-master主节点上的redis进程杀死：

[root@redis-master ~]

root 4500 14122 0 08:04 pts/1 00:00:00 grep redis

root 17265 1 0 04:00 ? 00:00:07 /usr/local/redis/bin/redis-server 0.0.0.0:6379

[root@redis-master ~]

root 4514 14122 0 08:04 pts/1 00:00:00 grep redis

查看redis-master主节点上的Keepalived日志

[root@redis-master ~]

OK

[master]

Mon May 7 07:29:17 CST 2018

Being master....

Run SLAVEOF cmd ...

OK Already connected to specified master

Run SLAVEOF NO ONE cmd ...

OK

[fault]

Mon May 7 08:05:00 CST 2018

同时redis-slave从节点上的日志显示：

[root@redis-slave ~]

Being slave....

Run SLAVEOF cmd ...

OK

[master]

Mon May 7 08:05:02 CST 2018

Being master....

Run SLAVEOF cmd ...

OK Already connected to specified master

Run SLAVEOF NO ONE cmd ...

OK

然后我们可以发现，redis-slave从节点已经接管服务，并且担任Master的角色了。

redis-slave从节点上已经接管过来VIP资源了（大概需要等待2秒左右的时间，vip资源就切过来了）

[root@redis-slave ~]

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

inet6 ::1/128 scope host

valid_lft forever preferred_lft forever

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

link/ether 52:54:00:dd:84:6b brd ff:ff:ff:ff:ff:ff

inet 192.168.10.206/24 brd 192.168.10.255 scope global eth0

inet 192.168.10.230/32 scope global eth0

inet6 fe80::5054:ff:fedd:846b/64 scope link

valid_lft forever preferred_lft forever

[root@redis-slave ~]

role:master

[root@redis-slave ~]

Could not connect to Redis at 192.168.10.205:6379: Connection refused

[root@redis-slave ~]

role:master

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

然后再恢复redis-master主节点的redis进程

[root@redis-master ~]

/var/run/redis.pid exists, process is already running or crashed

Redis is running...

[root@redis-master ~]

Starting Redis server...

Redis is running...

[root@redis-master ~]

root 4969 1 0 08:08 ? 00:00:00 /usr/local/redis/bin/redis-server 0.0.0.0:6379

root 4977 4976 0 08:08 ? 00:00:00 /bin/bash /usr/local/keepalived/scripts/redis_backup.sh 127.0.0.1 192.168.10.206 6379

root 4987 14122 0 08:08 pts/1 00:00:00 grep redis

[root@redis-master ~]

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

redis-ser 4969 root 4u IPv4 93698 0t0 TCP *:6379 (LISTEN)

redis-ser 4969 root 6u IPv4 93709 0t0 TCP 192.168.10.205:43299->192.168.10.206:6379 (ESTABLISHED)

查看redis-master上的Keepalived日志

[root@redis-master ~]

OK Already connected to specified master

Run SLAVEOF NO ONE cmd ...

OK

[fault]

Mon May 7 08:05:00 CST 2018

[BACKUP]

Mon May 7 08:08:34 CST 2018

Being slave....

Run SLAVEOF cmd ...

OK

查看redis-slave上的Keepalived日志

[root@redis-slave ~]

Being slave....

Run SLAVEOF cmd ...

OK

[master]

Mon May 7 08:05:02 CST 2018

Being master....

Run SLAVEOF cmd ...

OK Already connected to specified master

Run SLAVEOF NO ONE cmd ...

OK

[root@redis-master ~]

role:master

[root@redis-master ~]

role:slave

[root@redis-master ~]

role:master

发现redis-master的redis服务再次启动后，redis-master主节点成为salve角色了，redis-slave从节点还是master角色。

当redis-slave节点宕机或redis服务关闭后，redis-master节点再次接管服务成为master角色，如此循环~~

关闭redis-slave从节点的reids服务

[root@redis-slave ~]

root 15407 1 0 04:00 ? 00:00:10 /usr/local/redis/bin/redis-server 0.0.0.0:6379

root 22900 10868 0 08:11 pts/1 00:00:00 grep redis

[root@redis-slave ~]

root 22902 10868 0 08:11 pts/1 00:00:00 grep redis

查看redis-slave上的Keepalived日志

[root@redis-slave ~]

.......

[stop] //测试时发现，当redis-slave的redis服务关闭后，还需要重启或关闭keepalived，才能将vip资源漂到redis-master节点上，所以日志里也就会出现这个stop信息

Mon May 7 09:25:03 CST 2018

[BACKUP]

Mon May 7 09:25:04 CST 2018

Being slave....

Run SLAVEOF cmd ...

OK

查看redis-master上的Keepalived日志

[root@redis-master ~]

.......

[master]

Mon May 7 09:25:03 CST 2018

Being master....

Run SLAVEOF cmd ...

OK Already connected to specified master

Run SLAVEOF NO ONE cmd ...

OK

查看redis-master，发现VIP资源已经接管过来了（如果没有按时切过来的话，只需重启或关闭redis-slave节点那边的keepalived服务即可）

[root@redis-master ~]

1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN

link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00

inet 127.0.0.1/8 scope host lo

inet6 ::1/128 scope host

valid_lft forever preferred_lft forever

2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000

link/ether 52:54:00:b1:9c:93 brd ff:ff:ff:ff:ff:ff

inet 192.168.10.205/24 brd 192.168.10.255 scope global eth0

inet 192.168.10.230/32 scope global eth0

inet6 fe80::5054:ff:feb1:9c93/64 scope link

valid_lft forever preferred_lft forever

[root@redis-master ~]

role:master

[root@redis-master ~]

role:master

[root@redis-master ~]

Could not connect to Redis at 192.168.10.206:6379: Connection refused

发现redis-maste节点已经转变为master角色了。

同样，当reids-slave节点的redis服务重新启动后，它将成为slave角色。

[root@redis-slave ~]

/var/run/redis.pid exists, process is already running or crashed

Redis is running...

[root@redis-slave ~]

Starting Redis server...

Redis is running...

[root@redis-slave ~]

COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME

redis-ser 23244 root 4u IPv4 3049509 0t0 TCP *:6379 (LISTEN)

redis-ser 23244 root 6u IPv4 3049513 0t0 TCP dns.kevin.cn:44931->192.168.10.205:6379 (ESTABLISHED)

[root@redis-master ~]

role:master

[root@redis-master ~]

role:master

[root@redis-master ~]

role:slave

***************当你发现自己的才华撑不起野心时，就请安静下来学习吧***************

Log@X.X.B

奇客の遊園地

Redis+Keepalived高可用环境部署记录 – 散尽浮华 – 博客园

February 2019
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