linux下配置nginx+keepalived高可用的各种问题以及解决办法

本人的环境Centos 7 + nginx 1.12.2 + keepalived 1.3.5

nginx 主机 192.168.26.26 备机 192.168.26.126

安装：

在俩台服务器上安装nginx,keepalived

yum -y install keepalived : 安装keepalived
rpm -q -a keepalived: 查看安装版本号

keepalived配置文件:/etc/keepalived/keepalived.conf

关闭selinux

sed -i “s\SELINUX=enforcing\SELINUX=disabled\g” /etc/selinux/config
然后重启 shutdown -r now

替换/etc/keepalived/keepalived.conf 为我们写的keepalived.conf

备份：mv /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak

在主机上

global_defs
{router_id lb01script_user root
}
vrrp_script chk_nginx
{script "/etc/keepalived/ngx_check.sh"interval 2weight -20user root
}
vrrp_instance VI_1 {state MASTERinterface ens33virtual_router_id 51priority 150advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.26.50}track_script {chk_nginx}
}

在备机上：

global_defs
{router_id lb01script_user root
}
vrrp_script chk_nginx
{script "/etc/keepalived/ngx_check.sh"interval 2weight -20user root
}
vrrp_instance VI_1 {state BACKUPinterface ens33virtual_router_id 51priority 130advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.26.50}track_script {chk_nginx}
}

在俩台linux的/etc/keepalived/下创建ngx_check.sh

vi ngx_check.sh:

A=`ps -C nginx --no-header |wc -l` #查看系统中运行的nginx进程数，将结果赋值给A
if [ $A -eq 0 ];then  #如果A中的值等于0，表示无nginx运行。则启动echo "nginx is shutdown !!!"/usr/local/nginx/sbin/nginx #这里必须设置自己电脑上的nginx命令的位置。表示启动nginxsleep 2 #休眠2秒if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then #如果系统中运行的nginx进程数依然为0，表示nginx启动失败，则关闭keepalived服务service keepalived stopecho "keepalived is shutdown !!!"fi
fi

使得可以运行：chomd 777 /etc/keepalived/nginx.sh
你可以手动运行已测试脚本是否正确：
sh /etc/keepalived/nginx.sh

启动nginx、keepalived

启动nginx：/usr/local/nginx/sbin/nginx
启动keepalived：systemctl start keepalived.service
查看keepalived状态：systemctl status keepalived

测试

1.访问虚拟ip：http://192.168.26.50
2.stop主机上的nginx：/usr/local/nginx/sbin/nginx -s stop
3.ps -ef | grep nginx
会发现nginx依然运行，脚本生效。
4.ip addr 可以查看当前虚拟地址192.168.26.50挂载了否

问题解决：

查看日志：tail -f -n 50 /var/log/messages

因为tail命名是不会停止的,所以应该使用俩个Xshell(或其他连接工具)连接linux，方便一边操作一边查看日志

Unknown keyword:’}’、‘track_script{’、'chk_nginx等等

配置文件格式不正确:注意global_defs 以及 vrrp_script的俩个大括号{}必须换行。其他的使用到大括号的’{‘地方，确保正文与大括号间有空格。如 ‘track_script {->track_script这里有空格{’ 不能写为’track_script{->track_script这里没有空格{’

{ no match, ignoring…、Disabling track script chk_nginx since not found、Unable to access script `/etc/keepalived/nginx_check.sh`

确保vrrp_script的俩个大括号{}必须换行。确保track_script中的引用与vrrp_script声明的chk_nginx相同、vrrp_script中ngx_check.sh的路径要给正确

Unsafe permissions found for script ‘/etc/keepalived/ngx_check.sh’、Disabling track script chk_nginx due to insecure

global_defs 中不要使用enable_script_security,而应该使用user root.正如上面给出的keepalived.conf一样。

其他问题：

如果你复制我的keepalived.conf 和 ngx_check.sh。还是出现错误，你应该确保你要替换其中的一些路径以及IP地址。

日志信息：

May 26 18:59:33 localhost Keepalived_vrrp[1879]: VRRP_Script(chk_nginx) succeeded
表示使用脚本成功

当你关闭nginx后：
May 26 19:01:45 localhost Keepalived_vrrp[1879]: VRRP_Script(chk_nginx) timed out
May 26 19:01:45 localhost Keepalived_vrrp[1879]: /etc/keepalived/ngx_check.sh exited due to signal 15
May 26 19:01:45 localhost Keepalived_vrrp[1879]: VRRP_Script(chk_nginx) succeeded

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