keepalived介紹、用keepalived配置高可用集群
在這裏我們使用keepalived來實現高可用集群,因為heartbeat在centos6上有一些問題,影響實驗效果
keepalived通過VRRP(Virtual Router Redundancy Protocl)來實現高可用。
在這個協議裏會將多臺功能相同的路由器組成一個小組,這個小組裏會有1個master角色和N(N>=1)個backup角色。
master會通過組播的形式向各個backup發送VRRP協議的數據包,當backup收不到master發來的VRRP數據包時,就會認為master宕機了。此時就需要根據各個backup的優先級來決定誰成為新的mater。
二:用keepalived配置高可用集群
準備兩臺機器130和132,130作為master,132作為backup
兩臺機器都執行yum install -y keepalived
兩臺機器都安裝nginx,其中130上已經編譯安裝過nginx,132上需要yum安裝nginx: yum install -y nginx
設定vip為100
編輯130上keepalived配置文件,內容從
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_script chk_nginx { script "/usr/local/sbin/check_ng.sh" interval 3 } vrrp_instance VI_1 { state MASTER interface ens33 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass aminglinux>com } virtual_ipaddress { 192.168.188.100 } track_script { chk_nginx } }
130編輯監控腳本,
#!/bin/bash
#時間變量,用於記錄日誌
d=`date --date today +%Y%m%d_%H:%M:%S`
#計算nginx進程數量
n=`ps -C nginx --no-heading|wc -l`
#如果進程為0,則啟動nginx,並且再次檢測nginx進程數量,
#如果還為0,說明nginx無法啟動,此時需要關閉keepalived
if [ $n -eq "0" ]; then
/etc/init.d/nginx start
n2=`ps -C nginx --no-heading|wc -l`
if [ $n2 -eq "0" ]; then
echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
systemctl stop keepalived
fi
fi
給腳本755權限
systemctl start keepalived 130啟動服務
132上編輯配置文件
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_script chk_nginx {
script "/usr/local/sbin/check_ng.sh"
interval 3
}
vrrp_instance VI_1 {
state BACKUP
interface ens33
virtual_router_id 51
priority 90
advert_int 1
authentication {
auth_type PASS
auth_pass aminglinux>com
}
virtual_ipaddress {
192.168.188.100
}
track_script {
chk_nginx
}
}
132上編輯監控腳本
#時間變量,用於記錄日誌
d=`date --date today +%Y%m%d_%H:%M:%S`
#計算nginx進程數量
n=`ps -C nginx --no-heading|wc -l`
#如果進程為0,則啟動nginx,並且再次檢測nginx進程數量,
#如果還為0,說明nginx無法啟動,此時需要關閉keepalived
if [ $n -eq "0" ]; then
systemctl start nginx
n2=`ps -C nginx --no-heading|wc -l`
if [ $n2 -eq "0" ]; then
echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
systemctl stop keepalived
fi
fi
給腳本755權限
132上也啟動服務 systemctl start keepalived
先確定好兩臺機器上nginx差異,比如可以通過curl -I 來查看nginx版本
測試1:關閉master上的nginx服務
測試2:在master上增加iptabls規則
iptables -I OUTPUT -p vrrp -j DROP
測試3:關閉master上的keepalived服務
測試4:啟動master上的keepalived服務
keepalived介紹、用keepalived配置高可用集群