Keepalived知识点整理

高可用集群 keeaplived

高可用集群

集群类型

  • LB:load Balance 负载均衡

    LVS/HAProxy/nginx(http/upstream,stream/upstrream)

  • HA:Hight Availibility 高可用集群

    数据库,Redis

  • SPoF:Snigle Point of Fallure,解决单点故障

    HPC:High Performabce Computing高性能集群

系统可用性

SLA:Service-Level Agreement 服务等级协议(提供服务的企业与客户之间就服务的品质,水准,性能等方面所达成的双方共同可认可的协议或契约)

A=MTBF/(MTBF/MTTR)

99.9%:(60*24*30)*(1-0.9995)=21.6分钟 	#一般按一个月停机时间统计

系统故障

硬件故障:设计缺陷,wear out(损耗),非认为不可抗因素

软件故障:设计缺陷,bug

实现高可用

提升系统高性能的解决方案:降低MTTR-Mean Time To Repair(平均故障时间)

解决方案:家里冗余机制

  • active/passive 主/备
  • active/active 主/主
  • active->HEARTBEAT->passive
  • active<->HEATBEAT<->active

VRRP:Virtual Router Redundancy Protocol

虚拟路由冗余协议,解决静态网关单点风险

  • 物理层:路由器,三层交换机
  • 软件层:keepalived
VRRP相关术语
  • 虚拟路由器:Virtual Router
  • 虚拟路由器标识:VIRD(0.255),唯一标识虚拟路由器
  • VIP:Virtual IP
  • VMAV:Virtual MAC
  • 物理路由器
    • master:主设备
    • backup:备用设备
    • priority:优先级

VRRP相关技术:

通告:心跳,优先级等,周期性

工作方式:抢占式,非抢占式

安全认证:

  • 无认证
  • 简单字符认证:预共享密钥
  • MDS

工作模式:

  • 主/从:单虚拟路由
  • 主/主:主/备(虚拟路由器1),备/主(虚拟路由器2)

keepalived简介

Keepalived本质就是为ipvs服务的,它也不需要共享存储。IPVS其实就是一些规则,Keepalived主要的任务就是去调用ipvsadm命令,来生成规则,并自动实现将用户需要访问的地址转移到可用LVS节点实现

主要目的就是它自身启动为一个服务,它工作在多个LVS主机节点上,当前活动的节点叫做Master备用节点叫做Backup,Master会不停的向Backup节点通告自己的心跳,这种通告是基于VRRP协议的。Backup节点一旦接收不到Master的通告信息,它就会把LVS的VIP拿过来,并且把ipvs的规则也拿过来,在自己身上生效,从而替代Master节点

总的来说keepalived是vrrp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

keeplived架构

在这里插入图片描述

用户空间核心组件:

  • vrrp stack:VIP消息通告
  • checkers:检测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 Reflctor: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:针对网络目的的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)提供网络访问权限

配置文件组成部分

配置文件:/etc/keepalived/keepalived.conf

配置文件的组成:

  • GLOBAL CONFIGURATION

    Global definitions:定义邮件配置,route_id,vrrp配置,多播地址等

  • VRRP CONFIGURATION

    VRRP instance(s):定义每个vrrp虚拟路由器

  • LVS CONFIGURATION

    Virtual server group(s)

    Virtual server(s):LVS集群的VS和RS

配置文件主要部分的解释说明:
! Configuration File for keepalived
#全局配置
global_defs {
   
   notification_email {
   
   666688889@qq.com									#keepalived发生故障切换时邮件发送的目标邮箱,可以按行区分写多个
}
   notification_email_from keepalived@lanjinli.org	#发邮件的地址
   smtp_server 127.0.0.1							#邮件服务器地址
   smtp_connect_timeout 30							#邮件服务器连接timeout
   router_id ka1.lanjinli.org						#每个keepalived主机唯一标识,建议使用当前主机名,但节点多不影响
   vrrp_skip_check_adv_addr							#对所有通告报文都检查,会比较消耗性能,启用此配置后如果收到的通告报文和上一个报文是同一个路由器,则跳过检查,默认值为全检查
   vrrp_strict										#严格遵循vrrp协议,启用此配置后,如果在无VIP地址或配置了单播邻居,或在VRRP版本2中有IPV6地址的建议不适应此配置
   vrrp_garp_interval 0								#报文发送延迟
   vrrp_gna_interval 0								#消息发送延迟
   vrrp_mcast_group4 224.0.0.18						#指定组播IP地址范围
}


#配置虚拟路由器
vrrp_instance VI_1 {
   
    state BACKUP									#指定是主(MASTER)还是备(BACKUP)
    interface eth0									#绑定为当前虚拟路由器使用的物理接口,如:eth0,可以和VIP不再同一个网卡
    virtual_router_id 100							#每个虚拟路由器唯一标识,范围:0-255,每个虚拟路由器此值必须唯一,否则服务无法启动,同属一个虚拟路由器的多个keepalived节点必须相同,务必要确认在同一网络中此值必须唯一
    priority 80										#当前物理节点在此虚拟路由器的优先级,范围:1-255,值越大优先级越高,每个keepalived主机节点此值不同
    advert_int 1									#vrrp通告的时间间隔,默认为1s
    authentication {
   								#认证机制
        auth_type AH|PASS							#AH为IPSEC认证(不推荐),PASS为简单密码(建议使用)	
        auth_pass 1111								#预共享密钥,仅前8位有效,同一个虚拟路由器的多个keepalived节点必须一样
    }
    virtual_ipaddress {
   								#虚拟IP,生产环境可能指定上百个IP地址
        <IPADDR>/<MASK> brd <IPADDR> dev <STRING> scope <SCOPE> label <label>
        172.25.254.100								#指定VIP,不指定网卡,默认为eth0,注意:不指定/prefix,默认32
        172.25.254.101/24 dev eth1
        172.25.254.100/24 dev eth0 label eth0:1
    }
}
环境配置

四台机器

注: 四台机器都关闭了防火墙和SELinux

ka1

eth0 172.25.254.10

安装keepalived

关闭了防火墙和SELinux

[root@ka1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    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 group default qlen 1000
    link/ether 00:0c:29:92:51:bd brd ff:ff:ff:ff:ff:ff
    inet 172.25.254.10/24 brd 172.25.254.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::435f:2ba:94d2:582/64 scope link tentative noprefixroute dadfailed 
       valid_lft forever preferred_lft forever
    inet6 fe80::4da5:5424:6c11:6bc/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
#安装keepalived
[root@ka1 ~]# yum install keepalived -y
[root@ka1 ~]# systemctl stop firewalld.service
[root@ka1 ~]# setenforce 0
ka2

eth0 172.25.254.20

安装keepalived

关闭了防火墙和SELinux

[root@ka2 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    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 group default qlen 1000
    link/ether 00:0c:29:68:ef:05 brd ff:ff:ff:ff:ff:ff
    inet 172.25.254.20/24 brd 172.25.254.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet 172.25.254.100/24 scope global secondary eth0:1
       valid_lft forever preferred_lft forever
    inet6 fe80::435f:2ba:94d2:582/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
[root@ka2 ~]# yum install keepalived -y
[root@ka2 ~]# systemctl stop firewalld.service
[root@ka2 ~]# setenforce 0
realserver1

eth0 172.25.254.110

下载了httpd

[root@realserver1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    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 group default qlen 1000
    link/ether 00:0c:29:54:22:6a brd ff:ff:ff:ff:ff:ff
    inet 172.25.254.110/24 brd 172.25.254.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::4da5:5424:6c11:6bc/64 scope link tentative noprefixroute dadfailed 
       valid_lft forever preferred_lft forever
    inet6 fe80::435f:2ba:94d2:582/64 scope link tentative noprefixroute dadfailed 
       valid_lft forever preferred_lft forever
    inet6 fe80::d318:4046:600c:390c/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
[root@realserver1 ~]# yum install httpd -y
#配置httpd
[root@realserver1 ~]# echo hehehe > /var/www/html/index.html
#启动并设置开机自启
[root@realserver1 ~]# systemctl enable --now httpd
[root@realserver1 ~]# systemctl stop firewalld.service
[root@realserver1 ~]# setenforce 0
realserver2

eth0 172.25.254.120

下载了httpd

[root@realserver2 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    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 group default qlen 1000
    link/ether 00:0c:29:69:b5:ed brd ff:ff:ff:ff:ff:ff
    inet 172.25.254.120/24 brd 172.25.254.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet6 fe80::4da5:5424:6c11:6bc/64 scope link tentative noprefixroute dadfailed 
       valid_lft forever preferred_lft forever
    inet6 fe80::435f:2ba:94d2:582/64 scope link tentative noprefixroute dadfailed 
       valid_lft forever preferred_lft forever
    inet6 fe80::d318:4046:600c:390c/64 scope link tentative noprefixroute dadfailed 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
[root@realserver2 ~]# yum install httpd -y
#配置httpd
[root@realserver2 ~]# echo hehehe > /var/www/html/index.html
#启动并设置开机自启
[root@realserver2 ~]# systemctl enable --now httpd
[root@realserver2 ~]# systemctl stop firewalld.service
[root@realserver2 ~]# setenforce 0
实验1:

默认为抢占模式的实验,当一个主机上的VIP下线过后,另一台主机就获取VIP

ka1的keepalived配置文件

[root@ka1 ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   
   notification_email {
   
        6668889@qq.com
   }
   notification_email_from keepalived.lanjinli.org
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1.lanjinli.org
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
   vrrp_mcast_group4 224.0.0.18
}

vrrp_instance VI_1 {
   
    state MASTER
    interface eth0
    virtual_router_id 100
    priority 80
    advert_int 1
    authentication {
   
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
   
        172.25.254.100/24 dev eth0 label eth0:1
    }
}

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

ka2的keepalived配置文件

[root@ka2 ~]# vim /etc/keepalived/keepalived.conf 
! Configuration File for keepalived

global_defs {
   
   notification_email {
   
        6668889@qq.com
   }
   notification_email_from keepalived@lanjinli.org
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka2.lanjinli.org
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
   vrrp_mcast_group4 224.0.0.18
}

vrrp_instance VI_1 {
   
    state BACKUP
    interface eth0
    virtual_router_id 100
    priority 100
    advert_int 1
    authentication {
   
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
   
       172.25.254.100/24 dev eth0 label eth0:1
    }
}

......
#重启服务
[root@ka2 ~]# systemctl restart keepalived.service

检测:

#可以通过抓包查看数据的流向,抓的是发往组播上的包
[root@realserver1 ~]# tcpdump -i eth0 -nn host 224.0.0.18
#由于ka2的权重比较高,所以ka2包含的有VIP,tcp包从20发往224.0.0.18
[root@ka2 ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.25.254.20  netmask 255.255.255.0  broadcast 172.25.254.255
        inet6 fe80::435f:2ba:94d2:582  prefixlen 64  scopeid 0x20<link>
        inet6 fe80::4da5:5424:6c11:6bc  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:68:ef:05  txqueuelen 1000  (Ethernet)
        RX packets 30159  bytes 4025655 (3.8 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 43306  bytes 3358755 (3.2 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
        ether 00:0c:29:68:ef:05  txqueuelen 1000  (Ethernet)

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 1450  bytes 111001 (108.3 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1450  bytes 111001 (108.3 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:6b:1d:b7  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@ka2 ~]# 
#如果关闭ka2上的keepalived服务,则ka1上加入了VIP,tcp包从10发往224.0.0.18
[root@ka1 ~]# ifconfig
eth0: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.25.254.10  netmask 255.255.255.0  broadcast 172.25.254.255
        inet6 fe80::435f:2ba:94d2:582  prefixlen 64  scopeid 0x20<link>
        ether 00:0c:29:92:51:bd  txqueuelen 1000  (Ethernet)
        RX packets 38254  bytes 5109536 (4.8 MiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 41709  bytes 3230481 (3.0 MiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

eth0:1: flags=4163<UP,BROADCAST,RUNNING,MULTICAST>  mtu 1500
        inet 172.25.254.100  netmask 255.255.255.0  broadcast 0.0.0.0
        ether 00:0c:29:92:51:bd  txqueuelen 1000  (Ethernet)

lo: flags=73<UP,LOOPBACK,RUNNING>  mtu 65536
        inet 127.0.0.1  netmask 255.0.0.0
        inet6 ::1  prefixlen 128  scopeid 0x10<host>
        loop  txqueuelen 1000  (Local Loopback)
        RX packets 1535  bytes 117492 (114.7 KiB)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 1535  bytes 117492 (114.7 KiB)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

virbr0: flags=4099<UP,BROADCAST,MULTICAST>  mtu 1500
        inet 192.168.122.1  netmask 255.255.255.0  broadcast 192.168.122.255
        ether 52:54:00:6b:1d:b7  txqueuelen 1000  (Ethernet)
        RX packets 0  bytes 0 (0.0 B)
        RX errors 0  dropped 0  overruns 0  frame 0
        TX packets 0  bytes 0 (0.0 B)
        TX errors 0  dropped 0 overruns 0  carrier 0  collisions 0

[root@ka1 ~]# 
实验2

日志和子配置文件

独立日志:
#日志修改
[root@ka1 ~]# cat /etc/keepalived/keepalived.conf 
...
global_defs {
   
   notification_email {
   
    666688889@qq.com
   }
   notification_email_from keepalived@lanjinli.org
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1.lanjinli.org
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
   vrrp_mcast_group4 224.0.0.18
}

vrrp_instance VI_1 {
   
    state MASTER
    interface eth0
    virtual_router_id 100
    priority 100
    advert_int 1
    authentication {
   
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
   
        172.25.254.100/24 dev eth0 label eth0:1
    }
}


virtual_server 192.168.200.100 443 {
   

...
[root@ka1 ~]# cat /etc/sysconfig/keepalived 
# Options for keepalived. See `keepalived --help' output and keepalived(8) and
# keepalived.conf(5) man pages for a list of all options. Here are the most
# common ones :
#
# --vrrp               -P    Only run with VRRP subsystem.
# --check              -C    Only run with Health-checker subsystem.
# --dont-release-vrrp  -V    Dont remove VRRP VIPs & VROUTEs on daemon stop.
# --dont-release-ipvs  -I    Dont remove IPVS topology on daemon stop.
# --dump-conf          -d    Dump the configuration data.
# --log-detail         -D    Detailed log messages.
# --log-facility       -S    0-7 Set local syslog facility (default=LOG_DAEMON)
#

KEEPALIVED_OPTIONS="-D -S 6"

[root@ka1 ~]# 
#修改日志文件
[root@ka1 ~]# vim /etc/rsyslog.conf 
...
# Save boot messages also to boot.log
local7.*                                                /var/log/boot.log
local6.*                                                /var/log/keepalived.log
...
#重启服务
[root@ka1 ~]# systemctl restart keepalived.service  #使格式文件生效
[root@ka1 ~]# systemctl restart rsyslog.service 	#使定向文件生效
[root@ka1 ~]# systemctl restart keepalived.service 	#使生成日志文件
#查看是否生成日志文件
[root@ka1 ~]# ll /var/log/keepalived.log 
-rw-------. 1 root root 29956 Aug 12 02:14 /var/log/keepalived.log
[root@ka1 ~]# 
子配置文件

当生产环境复杂时, /etc/keepalived/keepalived.conf 文件中内容过多,不易管理

这时候可以将不同集群的配置,比如不同集群的VIP配置放在独立的子配置文件中利用include指令可以实现包含子配置文件

格式:

include pathfile
#编辑主配置文件
[root@ka1 ~]# cat /etc/keepalived/keepalived.conf 
...
   vrrp_gna_interval 0
   vrrp_mcast_group4 224.0.0.18
}

#vrrp_instance VI_1 {
   
#    state MASTER
#    interface eth0
#    virtual_router_id 100
#    priority 100
#    advert_int 1
#    authentication {
   
#        auth_type PASS
#        auth_pass 1111
#    }
#    virtual_ipaddress {
   
#        172.25.254.100/24 dev eth0 label eth0:1
#    }
#}
#定义子配置文件目录
include "/etc/keepalived/conf.d/*.conf"


virtual_server 192.168.200.100 443 {
   

...
#创建子配置文件目录
[root@ka1 ~]# mkdir -p /etc/keepalived/conf.d
[root@ka1 ~]# vim /etc/keepalived/conf.d/172.25.254.100.conf
[root@ka1 ~]# cat /etc/keepalived/conf.d/172.25.254.100.conf
vrrp_instance VI_1 {
   
	state MASTER
	interface eth0
	virtual_router_id 100
	priority 100
	advert_int 1
	authentication {
   
		auth_type PASS
		auth_pass 1111
	}
	virtual_ipaddress {
   
		172.25.254.100/24 dev eth0 label eth0:1
	}	
}
[root@ka1 ~]# 
#重启keepalived
[root@ka1 ~]# systemctl restart keepalived.service 
#查看是否运行成功获得了vip172.25.254.100,注意权重的问题
[root@ka1 ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    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 group default qlen 1000
    link/ether 00:0c:29:92:51:bd brd ff:ff:ff:ff:ff:ff
    inet 172.25.254.10/24 brd 172.25.254.255 scope global noprefixroute eth0
       valid_lft forever preferred_lft forever
    inet 172.25.254.100/24 scope global secondary eth0:1
       valid_lft forever preferred_lft forever
    inet6 fe80::435f:2ba:94d2:582/64 scope link tentative noprefixroute dadfailed 
       valid_lft forever preferred_lft forever
    inet6 fe80::4da5:5424:6c11:6bc/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: virbr0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.122.1/24 brd 192.168.122.255 scope global virbr0
       valid_lft forever preferred_lft forever
4: virbr0-nic: <BROADCAST,MULTICAST> mtu 1500 qdisc pfifo_fast master virbr0 state DOWN group default qlen 1000
    link/ether 52:54:00:6b:1d:b7 brd ff:ff:ff:ff:ff:ff
[root@ka1 ~]#
抢占模式和非抢占模式
非抢占模式(nopreempt)

在安装了keepalived过后,默认的是使用的是抢占模式,即当高权重高优先级主机在恢复在线后,会抢占优先级低的主机的master角色,这样会使vip在主机中来回切换,造成网络抖动,建议设置成非抢占模式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,非抢占模式下,如果原主机down机,vip迁址新主机,后续也会发生down时,仍会将vip迁回原主机

注: 要关闭vip抢占,必须要将各个keepalived服务器state配置成BACKUP

#可以通过抓包查看数据的流向,抓的是发往组播上的包
[root@realserver1 ~]# tcpdump -i eth0 -nn host 224.0.0.18
#ka1编写keepalived配置文件
[root@ka1 ~]# cat /etc/keepalived/keepalived.conf
...
global_defs {
   
   notification_email {
   
        6668889@qq.com
   }
   notification_email_from keepalived.lanjinli.org
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka1.lanjinli.org
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
   vrrp_mcast_group4 224.0.0.18
}

vrrp_instance VI_1 {
   
    #state MASTER
    state BACKUP
    interface eth0
    virtual_router_id 100
    priority 80				#优先级高
    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
    }
}
...


#ka2编写keepalived配置文件
[root@ka2 ~]# cat /etc/keepalived/keepalived.conf
...
global_defs {
   
   notification_email {
   
        6668889@qq.com
   }
   notification_email_from keepalived@lanjinli.org
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id ka2.lanjinli.org
   vrrp_skip_check_adv_addr
   #vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
   vrrp_mcast_group4 224.0.0.18
}

vrrp_instance VI_1 {
   
   
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