Keepalived安装与配置
1. Keepalived的安装
1.1. yum install方式
yum install -y keepalived
1.2. 安装包编译方式
更多安装包参考:http://www.keepalived.org/download.html
wget http://www.keepalived.org/software/keepalived-2.0.7.tar.gz
tar zxvf keepalived-2.0.7.tar.gz
cd keepalived-2.0.7
./configure --bindir=/usr/bin --sbindir=/usr/sbin --sysconfdir=/etc --mandir=/usr/share
make && make install
2. 常用配置
keepalived配置文件路径:/etc/keepalived/keepalived
。
2.1. MASTER(主机配置)
global_defs {
router_id proxy-keepalived
}
vrrp_script check_nginx {
script "/etc/keepalived/scripts/check_nginx.sh"
interval 3
weight 2
}
vrrp_instance VI_1 {
state BACKUP
interface eth2
virtual_router_id 15
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass xxx
}
track_script {
check_nginx
}
virtual_ipaddress {
180.101.115.139
218.98.38.29
}
nopreempt
notify_master "/etc/keepalived/keepalived_notify.sh master"
notify_backup "/etc/keepalived/keepalived_notify.sh backup"
notify_fault "/etc/keepalived/keepalived_notify.sh fault"
notify_stop "/etc/keepalived/keepalived_notify.sh stop"
}
2.2. BACKUP(备机配置)
global_defs {
router_id proxy-keepalived
}
vrrp_script check_nginx {
script "/etc/keepalived/scripts/check_nginx.sh"
interval 3
weight 2
}
vrrp_instance VI_1 {
state BACKUP
interface eth2
virtual_router_id 15
priority 99
advert_int 1
authentication {
auth_type PASS
auth_pass xxx
}
track_script {
check_nginx
}
virtual_ipaddress {
180.101.115.139
218.98.38.29
}
nopreempt
notify_master "/etc/keepalived/keepalived_notify.sh master"
notify_backup "/etc/keepalived/keepalived_notify.sh backup"
notify_fault "/etc/keepalived/keepalived_notify.sh fault"
notify_stop "/etc/keepalived/keepalived_notify.sh stop"
}
3. 注意事项
1、指定Nginx健康检测脚本:/etc/keepalived/scripts/check_nginx.sh
2、主备配置差别主要为(建议这么配置):
以下两种方式的配置,当其中一台机器keepalived挂掉后会自动VIP切到另一台机器,当挂掉机器keepalived恢复后不会抢占VIP,该方式可以避免机器恢复再次切VIP所带来的影响。
-
主机:(state BACKUP;priority 100)
-
备机:(state BACKUP;priority 99)
-
非抢占:nopreempt
或者:
-
主机:(state MASTER;priority 100)
-
备机:(state BACKUP;priority 100)
-
默认抢占
3、指定VIP
virtual_ipaddress {
180.101.115.139
218.98.38.29
}
4、可以指定为非抢占:nopreempt,即priority高不会抢占已经绑定VIP的机器。
5、制定绑定IP的网卡: interface eth2
6、可以指定keepalived状态变化通知
notify_master "/etc/keepalived/keepalived_notify.sh master"
notify_backup "/etc/keepalived/keepalived_notify.sh backup"
notify_fault "/etc/keepalived/keepalived_notify.sh fault"
notify_stop "/etc/keepalived/keepalived_notify.sh stop"
7、virtual_router_id 15值,主备值一致,但建议不应与集群中其他Nginx机器上的相同,如果同一个网段配置的virtual_router_id 重复则会报错,选择一个不重复的0~255之间的值,可以用以下命令查看已存在的vrid。
tcpdump -nn -i any net 224.0.0.0/8
4. 常用脚本
4.1. Nginx健康检测脚本
在Nginx配置目录下(/etc/nginx/conf.d/)增加health.conf的配置文件,该配置文件用于配置Nginx health的接口。
server {
listen 80 default_server;
server_name localhost;
default_type text/html;
return 200 'Health';
}
Nginx健康检测脚本:/etc/keepalived/scripts/check_nginx.sh
4.1.1. 检查接口调用是否为200
#!/bin/sh
set -x
timeout=30 #指定默认30秒没返回200则为非健康,该值可根据实际调整
if [ -n ${timeout} ];then
httpcode=`curl -sL -w %{http_code} -m ${timeout} http://localhost -o /dev/null`
else
httpcode=`curl -sL -w %{http_code} http://localhost -o /dev/null`
fi
if [ ${httpcode} -ne 200 ];then
echo `date`': nginx is not healthy, return http_code is '${httpcode} >> /etc/keeperalived/keepalived.log
killall keepalived
exit 1
else
exit 0
fi
4.1.2. 检查Nginx进程是否运行
#!/bin/sh
if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
echo "$(date) nginx pid not found">>/etc/keepalived/keepalived.log
killall keepalived
fi
4.2. Keepalived状态通知脚本
#!/bin/bash
set -x
warn_receiver=$1
ip=$(ifconfig bond0|grep inet |awk '{print $2}')
warningInfo="${ip}_keepalived_changed_status_to_$1"
warn-report --user admin --key=xxxx --target=${warn_receiver} ${warningInfo}
echo $(date) $1 >> /etc/keepalived/status
说明:
- ip获取本机IP,本例中IP获取是bond0的IP,不同机器网卡名称不同需要修改为对应网卡名称。
- 告警工具根据自己指定。
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