高可用集群KEEPALIVED

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一.高可用集群

1.1 集群类型

LB: 负载均衡
HA: 高可用集群
SPoF: 解决单点故障
HPC: 高性能集群

1.2 系统可用性

A=MTBF/(MTBF+MTTR)

99.95%:(60*24*30)*(1-0.9995)=21.6分钟 #一般按一个月停机时间统计

1.3 实现高可用

提升系统高可用的解决方案：降低平均故障时间

解决方案：建立冗余机制

active/passive 主/备
active/active 双主
active --> HEARTBEAT --> passive
active HEARTBEAT active

二.Keepalived 部署

2.1 keepalived 简介

vrrp 协议的软件实现，原生设计目的为了高可用 ipvs服务

功能：

基于vrrp协议完成地址流动
为vip地址所在的节点生成ipvs规则(在配置文件中预先定义)
为ipvs集群的各RS做健康状态检测
基于脚本调用接口完成脚本中定义的功能，进而影响集群事务，以此支持nginx、haproxy等服务

2.2 Keepalived 架构

用户空间核心组件：

vrrp stack：VIP消息通告

checkers：监测real server

system call：实现 vrrp 协议状态转换时调用脚本的功能

SMTP：邮件组件 IPVS

wrapper：生成IPVS规则

Netlink Reflector：网络接口

WatchDog：监控进程

控制组件：提供keepalived.conf 的解析器，完成Keepalived配置
IO复用器：针对网络目的而优化的自己的线程抽象
内存管理组件：为某些通用的内存管理功能（例如分配，重新分配，发布等）提供访问权限

2.3 Keepalived 环境准备

2.3.1 ka1配置

[root@ka1 ~]# yum install keepalived.x86_64    -y
[root@ka1 ~]# systemctl start keepalived.service

[root@ka1 ~]# vim /etc/keepalived/keepalived.conf

2.3.2 ka2配置

[root@ka2 ~]# yum install keepalived.x86_64    -y
[root@ka2 ~]# systemctl start keepalived.service

2.3.3 测试

2.4 启用keepalived日志功能

[root@ka1 ~]# cat /etc/sysconfig/keepalived

KEEPALIVED_OPTIONS="-D -S 6"

[root@ka1 ~]# vim /etc/rsyslog.conf

[root@ka1 ~]# systemctl restart keepalived.service
[root@ka1 ~]# systemctl restart rsyslog.service

2.5 实现独立子配置文件

[root@ka1 ~]# mkdir /etc/keepalived/conf.d
[root@ka1 ~]# vim /etc/keepalived/keepalived.conf

三.Keepalived 企业应用示例

3.1 抢占模式和非抢占模式

默认为抢占模式preempt，即当高优先级的主机恢复在线后，会抢占低先级的主机的master角色，这样会使vip在KA主机中来回漂移，造成网络抖动，建议设置为非抢占模式 nopreempt ，即高优先级主机恢复后，并不会抢占低优先级主机的master角色非抢占模块下,如果原主机down机, VIP迁移至的新主机, 后续也发生down时,仍会将VIP迁移回原主机

注意：要关闭 VIP抢占，必须将各 keepalived 服务器state配置为BACKUP

ka1 主机配置

[root@ka1 ~]# vim /etc/keepalived/conf.d/route.conf
[root@ka1 ~]# cat  /etc/keepalived/conf.d/route.conf
vrrp_instance VI_1 {
        state BACKUP                     #必须将keepalived服务器设置为backup
        interface eth0
        virtual_router_id 100          
        priority 100                     #优先级高 
        nopreempt                        #非抢占模式
        advert_int 1
        authentication {
                auth_type PASS
                auth_pass 1111
        }
        virtual_ipaddress {
                172.25.254.100/24 dev eth0 label eth0:1
        }
}

[root@ka1 ~]# systemctl restart keepalived.service

ka2配置

[root@ka2 ~]# vim /etc/keepalived/keepalived.conf

vrrp_instance VI_1 {
    state BACKUP                  #必须将keepalived服务器设置为backup
    interface eth0
    virtual_router_id 100
    priority 80                   #低优先级
    advert_int 1
    nopreempt                     #非抢占模式
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.100/24 dev eth0 label eth0:1

    }
}

3.2.2 抢占延迟模式 preempt_delay

抢占延迟模式，即优先级高的主机恢复后，不会立即抢回VIP，而是延迟一段时间（默认300s）再抢回 VIP

 preempt_delay #     
#指定抢占延迟时间为#s，默认延迟300s

注意：需要各keepalived服务器state为BACKUP,并且不要启用 vrrp_strict

ka1配置

ka2配置

测试

[root@ka1 ~]# watch -n 1 ifconfig

关闭ka1的keepalived后vip跳转到ka2

开启ka1后，vip不会立即跳回ka1，而是根据设置的延时抢占时间后抢占vip

3.3 VIP单播配置

默认keepalived主机之间利用多播相互通告消息，会造成网络拥塞，可以替换成单播，减少网络流量

注意：启用 vrrp_strict 时，不能启用单播

ka1配置

ka2配置

3.4 Keepalived 通知脚本配置

创建通知脚本

#!/bin/bash
mail_dest='1421304181@qq.com'

mail_send()
{
        mail_subj='$HOSTNAME to be $1 vip move'
        mail_msg='`date +%F\ %T`:vrrp move $HOSTNAME chage $1'
        echo $mail_msg | mail -s "mail_sub" $mail_dst
}

case $1 in
        master)
                send_message master
                ;;
        backup)
                send_message backup
                ;;
        fault)
                send_message fault
                ;;
        *)
                ;;
esac

给执行权限

[root@ka1 ~]# chmod +x  /etc/keepalived/mail.sh

[root@ka1 ~]# yum install sendmail   #下载邮件服务器

添加邮件配置

[root@ka1 ~]# cat /etc/mail.rc
 set from=1421304181@qq.com
 set smtp=smtp.qq.com
 set smtp-auth-user=1421304181@qq.com
 set smtp-auth-password=fmgqbgkvyunaifci
 set smtp-auth=login
 set ssl-verify=ignore

测试邮件

[root@ka1 ~]# echo tes | mail -s test 1421304181@qq.com

调用脚本：在 vrrp_instance VI_1 语句块的末尾加下面行

notify_master "/etc/keepalived/notify.sh master"
 notify_backup "/etc/keepalived/notify.sh backup"
 notify_fault "/etc/keepalived/notify.sh fault"

双主分别实现httpd和mysql服务的调度

在RS1和RS2中准备httpd和mysql环境

在RS1中：
[root@rs1 ~]# ip addr add 172.25.254.200/32 dev lo
 [root@rs1 ~]# yum install mariadb-server  -y
 root@rs1 ~]# vim /etc/my.cnf
 server-id=1
 [root@rs1 ~]# systemctl enable --now mariadb
 [root@rs1 ~]# mysql -e "grant ALL on *.* to lee@'%' identified by 'lee'"
 [root@rs1 ~]# mysql -ulee -plee -h172.25.254.101 -e 'select @@server_id'
 +-------------+
 | @@server_id |
 +-------------+
 |           
             1 |
 +-------------+

在RS2中：
[root@rs2 ~]# ip addr add 172.25.254.200/32 dev lo
 [root@rs2 ~]# yum install mariadb-server  -y
 [root@rs2 ~]# vim /etc/my.cnf
 server-id=2
 [root@rs2 ~]# systemctl enable --now mariadb
 [root@rs2 ~]# mysql -e "grant ALL on *.* to lee@'%' identified by 'lee'"
 [root@rs2 ~]# mysql -ulee -plee -h172.25.254.102 -e 'select @@server_id'
 +-------------+
 | @@server_id |
 +-------------+
 |           
             1 |
 +-------------+

ka1配置

#配置双主模式
[root@rhel7-ka1 ~]# vim /etc/keepalived/keepalived.conf
 vrrp_instance web {
 state MASTER
 interface ens33
 virtual_router_id 100
 priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.100 dev ens33 label ens33:0
    }
 }
 vrrp_instance sql {
    state BACKUP
    interface ens33
    virtual_router_id 200
    priority 80
    advert_int 1
   authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.200 dev ens33 label ens33:1
    }
 }
 include "/etc/keepalived/conf.d/web.conf"
 include "/etc/keepalived/conf.d/sql.conf"
 [root@rhel7-ka1 ~]# vim /etc/keepalived/conf.d/web.conf
 virtual_server 172.25.254.100 80 {
    delay_loop 6
    lb_algo wrr
    lb_kind DR
    protocol TCP
    sorry_server 172.25.254.30 80
    real_server 172.25.254.101 80 {
        weight 1
        TCP_CHECK {
            connect_timeout 5
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }
    real_server 172.25.254.102 80 {
        weight 1
        HTTP_GET {
            url {
                path /
                status_code 200
            }
            connect_timeout 1
            nb_get_retry 3
            delay_before_retry 1
        }
    }
 }
 [root@rhel7-ka1 ~]# vim /etc/keepalived/conf.d/sql.conf
 virtual_server 172.25.254.200 3306 {
    delay_loop 3
    lb_algo rr
    lb_kind DR
    protocol TCP
    real_server 172.25.254.101 3306 {
        weight 1
        TCP_CHECK {
            connect_timeout 5
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
    real_server 172.25.254.102 3306 {
        weight 1
        TCP_CHECK {
            connect_timeout 5
            nb_get_retry 3
            delay_before_retry 3
            connect_port 3306
        }
    }
 }

ka2配置

[root@ka1 keepalived]# vim /etc/keepalived/keepalived.conf
 vrrp_instance web {
    state BACKUP                #备机
    interface eth0
    virtual_router_id 50
    priority 80
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.100 dev eth0 label eth0:1
    }
 }
 vrrp_instance sql {
    state MASTER            #主机
    interface eth0
    virtual_router_id 60
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        172.25.254.200 dev eth0 label eth0:1
    }
 }
 include "/etc/keepalived/conf.d/web.conf"
 include "/etc/keepalived/conf.d/sql.conf"
[root@ka1 keepalived]#  vim /etc/keepalived/conf.d/web.conf
 virtual_server 172.25.254.100 80 {
    delay_loop 6
    lb_algo wrr
    lb_kind DR
    protocol TCP
    sorry_server 172.25.254.30 80
    real_server 172.25.254.10 80 {
        weight 1
        TCP_CHECK {
            connect_timeout 5
            nb_get_retry 3
            delay_before_retry 3
            connect_port 80
        }
    }
    real_server 172.25.254.102 80 {
        weight 1
        HTTP_GET {
            url {
                path /
                status_code 200
            }
            connect_timeout 1
            nb_get_retry 3
            delay_before_retry 1
        }
    }
 }
 [root@rhel7-ka2 ~]# vim /etc/keepalived/conf.d/web.conf
 virtual_server 172.25.254.200 3306 {
    delay_loop 3
    lb_algo rr
    lb_kind DR
    protocol TCP
    real_server 172.25.254.101 3306 {
        weight 1
        TCP_CHECK {
            connect_timeout 5
            nb_get_retry 3
            delay_before_retry 3
connect_port 3306
 }
 }
 real_server 172.25.254.102 3306 {
 weight 1
 TCP_CHECK {
 connect_timeout 5
 nb_get_retry 3
 delay_before_retry 3
 connect_port 3306
 }
 }
 }

使用ipvsadm查看

[root@ka1 keepalived]#  ipvsadm -Ln
 IP Virtual Server version 1.2.1 (size=4096)
 Prot LocalAddress:Port Scheduler Flags
    -> RemoteAddress:Port               Forward Weight ActiveConn InActConn

TCP  172.25.254.100:80 wrr
    -> 172.25.254.100:80                  Route    1        0        0
    -> 172.25.254.101:80                  Route    1        0        0
TCP  172.25.254.200:3306 rr 
    -> 172.25.254.101:3306                Route    1        0        0
    -> 172.25.254.102:3306                Route    1        0        0

测试

[root@ka1 keepalived]#  mysql -ulee -plee -h172.25.254.200 -e 'select @@server_id'
 +-------------+
 | @@server_id |
 +-------------+
 |           
2 |
 +-------------+
[root@ka2 keepalived]#  mysql -ulee -plee -h172.25.254.200 -e 'select @@server_id'
 +-------------+
 | @@server_id |
 +-------------+
 |           
1 |
 +-------------+
[root@ka1 keepalived]#  mysql -ulee -plee -h172.25.254.200 -e 'select @@server_id'

利用脚本实现主从角色切换

[root@ka1 keepalived]# vim /mnt/check_lee.sh
 #!/bin/bash
 [ ！ -f "/mnt/lee" ]
[root@ka1 keepalived]#  chmod  +x /mnt/check_lee.sh
[root@ka1 keepalived]# vim /etc/keepalived/keepalived.conf

 vrrp_script check_lee {
 script "/mnt/check_lee.sh"
 interval 1
 weight -30
 fall 2
 rise 2
 timeout 2
 }
 vrrp_instance web {
 state MASTER
 interface ens33
 virtual_router_id 50
 priority 100
 advert_int 1
 }
 authentication {
 auth_type PASS
 auth_pass 1111
 }
 virtual_ipaddress {
 172.25.254.100 dev ens33 label ens33:0
 }
 track_script {
 check_lee
 }
[root@ka1 keepalived]# touch /mnt/lee
[root@ka1 keepalived]# tail -f /var/log/messages

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高可用集群KEEPALIVED

一.高可用集群

1.1 集群类型

1.2 系统可用性

1.3 实现高可用

二.Keepalived 部署

2.1 keepalived 简介

2.2 Keepalived 架构

2.3 Keepalived 环境准备

2.3.1 ka1配置

2.3.2 ka2配置

2.3.3 测试

2.4 启用keepalived日志功能

2.5 实现独立子配置文件

三.Keepalived 企业应用示例

3.1 抢占模式和非抢占模式

ka1 主机配置

ka2配置

3.2.2 抢占延迟模式 preempt_delay

注意：需要各keepalived服务器state为BACKUP,并且不要启用 vrrp_strict

ka1配置

ka2配置

测试

3.3 VIP单播配置

ka2配置

3.4 Keepalived 通知脚本配置

创建通知脚本

给执行权限

添加邮件配置

测试邮件

调用脚本：在 vrrp_instance VI_1 语句块的末尾加下面行

双主分别实现httpd和mysql服务的调度

ka1配置

ka2配置

使用ipvsadm查看

测试

利用脚本实现主从角色切换

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