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 {
root@localhost
}
notification_email_from kaadmin@localhost
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='root@localhost'
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