2Keepalived

Posted 2021-01-23 hanshanxiaoheshang

Keepalived实例演示：

利用keepalived流动一个VIP，在提供LVS的高可用以及实现对LVS后端的real server做健康状态检测，最后实现高可用nginx。

 

 

 

 

HA Cluster配置前提：

1、本机的主机名，要与hostname(uname -n)获得的名称保持一致；

CentOS 6: /etc/sysconfig/network

CentOS 7: hostnamectl set-hostname HOSTNAME

 

各节点要能互相解析主机名；一般建议通过hosts文件进行解析；

 

2、各节点时间同步；

 

3、确保iptables及selinux不会成为服务阻碍；

 

virtual_ipaddress {

<IPADDR>/<MASK> brd <IPADDR> dev <STRING> scope <SCOPE> label <LABEL>

192.168.200.17/24 dev eth1

192.168.200.18/24 dev eth2 label eth2:1

}

 

nopreempt：非抢占模式；默认为抢占模式；

 

vrrp_sync_group VG_1 {

group {

VI_1   # name of vrrp_instance (below)

VI_2  # One for each moveable IP.

}

}

 

vrrp_instance VI_1 {

eth0

vip

}

 

vrrp_instance VI_2 {

eth1

dip

}

 

 

总结：

1、日志？

2、每个vrrp_instance需要专用的组播地址；

 

回顾：

 

keepalived: vrrp协议的实现；

虚拟路由器：

MASTER，BACKUP

VI：Virtual Instance

 

keepalived.conf

GLOBAL

VRRP

LVS

 

keepalived(2)

 

在vi中的主机状态发生改变生发送通知：

# notify scripts, alert as above

notify_master <STRING>|<QUOTED-STRING>

notify_backup <STRING>|<QUOTED-STRING>

notify_fault <STRING>|<QUOTED-STRING>

notify <STRING>|<QUOTED-STRING>

smtp_alert

 

配置示例：

! Configuration File for keepalived

 

global_defs {

notification_email {

[email protected]

}

notification_email_from [email protected]

smtp_server 127.0.0.1

smtp_connect_timeout 30

router_id LVS_DEVEL

vrrp_mcast_group4 224.0.1.118

}

 

vrrp_script chk_mt {

script "[[ -f /etc/keepalived/down ]] && exit 1 || exit 0"

interval 1

weight -20

}

 

vrrp_instance VI_1 {

state MASTER

interface eno16777736

virtual_router_id 144

priority 100

advert_int 1

authentication {

auth_type PASS

auth_pass 84ae57f7f4f6

}

virtual_ipaddress {

172.16.100.88/16 dev eno16777736 label eno16777736:1

}

 

track_script {

chk_mt

}

 

notify_master "/etc/keepalived/notify.sh master"

notify_backup "/etc/keepalived/notify.sh backup"

notify_fault "/etc/keepalived/notify.sh fault"

}

 

virtual_server 172.16.100.88 80 {

delay_loop 6

lb_algo wrr

lb_kind DR

nat_mask 255.255.0.0

protocol TCP

sorry_server 127.0.0.1 80

 

real_server 172.16.100.6 80 {

weight 1

HTTP_GET {

url {

path /

status_code 200

}

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

real_server 172.16.100.69 80 {

weight 2

HTTP_GET {

url {

path /

status_code 200

}

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

}

}

 

通知脚本：

#!/bin/bash

# Author: MageEdu <[email protected]>

# description: An example of notify script

#

 

vip=172.16.100.88

contact=‘[email protected]‘

 

notify() {

mailsubject="`hostname` to be $1: $vip floating"

mailbody="`date ‘+%F %H:%M:%S‘`: vrrp transition, `hostname` changed to be $1"

echo $mailbody | mail -s "$mailsubject" $contact

}

 

case "$1" in

master)

notify master

exit 0

;;

backup)

notify backup

exit 0

;;

fault)

notify fault

exit 0

;;

*)

echo ‘Usage: `basename $0` {master|backup|fault}‘

exit 1

;;

esac

 

keepalived：

HTTP_GET

SSL_GET(https)

TCP_CHECK

 

示例：

HTTP_GET {

url {

path /

status_code 200

}

connect_timeout 3

nb_get_retry 3

delay_before_retry 3

}

 

TCP_CHECK {

connect_timeout 3

}

 

HA Services:

nginx

 

 

100: -25

96: -20 79 --> 99 --> 79

 

博客作业：

keepalived 高可用 ipvs

nginx

 

active/active