zabbix监控部署keepalived高可用

zabbix监控部署keepalived高可用

脑裂

在高可用（HA）系统中，当联系2个节点的“心跳线”断开时，本来为一整体、动作协调的HA系统，就分裂成为2个独立的个体。由于相互失去了联系，都以为是对方出了故障。两个节点上的HA软件像“裂脑人”一样，争抢“共享资源”、争起“应用服务”，就会发生严重后果——或者共享资源被瓜分、两边“服务”都起不来了；或者两边“服务”都起来了，但同时读写“共享存储”，导致数据损坏（常见如数据库轮询着的联机日志出错）。

• 1、对付HA系统“裂脑”的对策，目前达成共识的的大概有以下几条：
  （1）添加冗余的心跳线，例如：双心跳线（心跳线也HA），尽量减少“裂脑”发生几率；
  （2）启用磁盘锁。正在服务一方锁住共享磁盘，“裂脑”发生时，让对方完全“抢不走”共享磁盘资源。但使用锁磁盘也会有一个不小的问题，如果占用共享盘的一方不主动“解锁”，另一方就永远得不到共享磁盘。现实中假如服务节点突然死机或崩溃，就不可能执行解锁命令。后备节点也就接管不了共享资源和应用服务。于是有人在HA中设计了“智能”锁。即：正在服务的一方只在发现心跳线全部断开（察觉不到对端）时才启用磁盘锁。平时就不上锁了
  （3）设置仲裁机制。例如设置参考IP（如网关IP），当心跳线完全断开时，2个节点都各自ping一下参考IP，不通则表明断点就出在本端。不仅“心跳”、还兼对外“服务”的本端网络链路断了，即使启动（或继续）应用服务也没有用了，那就主动放弃竞争，让能够ping通参考IP的一端去起服务。更保险一些，ping不通参考IP的一方干脆就自我重启，以彻底释放有可能还占用着的那些共享资源

• 2、脑裂产生的原因
  一般来说，脑裂的发生，有以下几种原因：
  （1）高可用服务器对之间心跳线链路发生故障，导致无法正常通信
  （2）因心跳线坏了（包括断了，老化）
  （3）因网卡及相关驱动坏了，ip配置及冲突问题（网卡直连）
  （4）因心跳线间连接的设备故障（网卡及交换机）
  （5）因仲裁的机器出问题（采用仲裁的方案）
  （6）高可用服务器上开启了 iptables防火墙阻挡了心跳消息传输
  （7）高可用服务器上心跳网卡地址等信息配置不正确，导致发送心跳失败
  （8）其他服务配置不当等原因，如心跳方式不同，心跳广插冲突、软件Bug等

对脑裂的监控应在备用服务器上进行，通过添加zabbix自定义监控进行。
监控什么信息呢？监控备上有无VIP地址
备机上出现VIP有两种情况：
（1）发生了脑裂
（2）正常的主备切换
监控只是监控发生脑裂的可能性，不能保证一定是发生了脑裂，因为正常的主备切换VIP也会到备份节点上。

使用zabbix监控脑裂

Zabbix： 192.168.253.139 lamp架构、zabbix-server、zabbix-agentd、keepalived、nginx
Agent1：192.168.253.130 zabbix-agentd keepalived、nginx
VIP：192.168.253.111

使用zabbix监控脑裂

zabbix­server和 zabbix­agent已经配置好了zabbix监控
接下来就给zabbix­server和 zabbix­agent配置好keepalived高可用，但是注意的是nginx使 用的端口改为8080

server

[root@server zabbix]# yum -y install vim wget gcc gcc-c++
[root@server zabbix]# yum -y install keepalived nginx
[root@server zabbix]# vim /etc/nginx/nginx.conf
 server {
        listen      8080 default_server;
        listen       [::]:8080 default_server;
        server_name  _;
        root         /usr/share/nginx/html;
[root@server zabbix]# cd /usr/share/nginx/html/
[root@server html]# echo "master node" > index.html
[root@server html]# systemctl restart nginx.service
[root@server html]# systemctl enable nginx.service
Created symlink /etc/systemd/system/multi-user.target.wants/nginx.service → /usr/lib/systemd/system/nginx.service.
[root@server html]# 

[root@agent1 ~]# yum -y install vim wget gcc gcc-c++
[root@agent1 ~]# yum -y install keepalived nginx
[root@agent1 ~]#  vim /etc/nginx/nginx.conf
 server {
        listen       8080 default_server;
        listen       [::]:8080 default_server;
        server_name  _;
        root         /usr/share/nginx/html;

配置VIP

[root@server html]# vim /etc/sysconfig/network-scripts/ifcfg-ens33
IPADDR1=192.168.253.111 
PREFIX1=32
[root@server html]# systemctl restart NetworkManager
[root@server html]# nmcli connection up ens33
连接已成功激活（D-Bus 活动路径：/org/freedesktop/NetworkManager/ActiveConnection/3）

修改内核参数，开启侦听VIP功能 ­server和 agent:

[root@server html]# vim /etc/sysctl.conf
[root@server html]# sysctl -p
net.ipv4.ip_nonlocal_bind = 1

[root@agent1 html]# vim /etc/sysctl.conf
[root@agent1 html]# sysctl -p
net.ipv4.ip_nonlocal_bind = 1

让keepalived监控nginx负载均衡

[root@agent1 html]# mkdir /scripts
[root@agent1 html]#  cd /scripts/
[root@agent1 scripts]# vim check.sh
[root@agent1 scripts]# cat check.sh
#!/bin/bash 
nginx_status=`ps -ef | grep -v "grep" | grep "nginx" | wc -l` 
if [ $nginx_status -lt 1 ];then 
	systemctl stop keepalived 
fi
[root@agent1 scripts]# chmod +x check.sh
[root@agent1 scripts]# vim notify.sh
[root@agent1 scripts]# cat notify.sh
#!/bin/bash
VIP=$2
sendmail () { 
	subject="${VIP}'s server keepalived state is translate"
	content="`date +'%F %T'`: `hostname`'s state change to master"
	echo $content | mail -s "$subject" m13720252783@163.com
}
case "$1" in 
  master)
	nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
	if [ $nginx_status -lt 1 ];then
		systemctl start nginx
	fi
	sendmail
   ;;
   backup)								        
	nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
	if [ $nginx_status -gt 0 ];then
		systemctl stop nginx
	fi
   ;;
   *) 
	echo "Usage:$0 master|backup VIP"
   ;;
esac
[root@agent1 scripts]# chmod +x notify.sh


[root@server html]# mkdir /scripts
[root@server html]# cd /scripts/
[root@server scripts]# scp root@192.168.223.130:/scripts/check.sh .
ssh: connect to host 192.168.223.130 port 22: Connection refused
[root@server scripts]# scp root@192.168.253.130:/scripts/check.sh .
The authenticity of host '192.168.253.130 (192.168.253.130)' can't be established.
ECDSA key fingerprint is SHA256:VSp2FN4X9cyPq6nNQhJWnsujJzeaR61q3Otsk1xU9zY.
Are you sure you want to continue connecting (yes/no/[fingerprint])? yes
Warning: Permanently added '192.168.253.130' (ECDSA) to the list of known hosts.
root@192.168.253.130's password: 
check.sh                                                                                      100%  140    89.4KB/s   00:00    
[root@server scripts]# scp root@192.168.253.130:/scripts/notify.sh .
root@192.168.253.130's password: 
notify.sh                                                                                     100%  593   227.8KB/s   00:00    
[root@server scripts]# chmod +x check.sh
[root@server scripts]# chmod +x notify.sh

配置keepalived

[root@server scripts]# vim /etc/keepalived/keepalived.conf
[root@server scripts]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id rww01
}

vrrp_script nginx_check { 
    script "/scripts/check.sh"
    interval 10
    weight -20
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.253.111
    }
    track_script { 
	nginx_check
    }
    notify_master "/scripts/notify.sh master 192.168.253.111"
    notify_backup "/scripts/notify.sh backup 192.168.253.111"
}

virtual_server 192.168.253.111 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.253.139 80 {
        weight 1
        TCP_CHECK {
	    connect_port 80
            connect_timeout 3
	        nb_get_retry 3
            delay_before_retry 3
        }
    }


    real_server 192.168.253.130 80 {
        weight 1
        TCP_CHECK { 
	    connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@server scripts]# systemctl restart keepalived.service
[root@server scripts]# systemctl enable keepalived.service
Created symlink /etc/systemd/system/multi-user.target.wants/keepalived.service → /usr/lib/systemd/system/keepalived.service.
[root@server scripts]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:68:24:b7 brd ff:ff:ff:ff:ff:ff
    inet 192.168.253.139/24 brd 192.168.253.255 scope global dynamic noprefixroute ens33
       valid_lft 1320sec preferred_lft 1320sec
    inet 192.168.253.111/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::61fb:85dd:bc5b:a789/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
3: docker0: <NO-CARRIER,BROADCAST,MULTICAST,UP> mtu 1500 qdisc noqueue state DOWN group default 
    link/ether 02:42:4c:c2:9a:83 brd ff:ff:ff:ff:ff:ff
    inet 172.17.0.1/16 brd 172.17.255.255 scope global docker0
       valid_lft forever preferred_lft forever

agent1配置keepalived

[root@agent1 scripts]# vim /etc/keepalived/keepalived.conf
[root@agent1 scripts]# systemctl restart keepalived.service
[root@agent1 scripts]# systemctl enable keepalived.service
Created symlink /etc/systemd/system/multi-user.target.wants/keepalived.service → /usr/lib/systemd/system/keepalived.service.

测试

[root@server scripts]# systemctl stop nginx
[root@server scripts]# systemctl restart keepalived.service
[root@agent1 scripts]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel state UP group default qlen 1000
    link/ether 00:0c:29:d8:b9:ca brd ff:ff:ff:ff:ff:ff
    inet 192.168.253.130/24 brd 192.168.253.255 scope global dynamic noprefixroute ens33
       valid_lft 1438sec preferred_lft 1438sec
    inet 192.168.253.111/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::dc90:bd3b:eb11:638c/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

在备份节点中，新建脚本，检查VIP

[root@agent1 scripts]# vim check_backupip.sh
[root@agent1 scripts]# cat check_backupip.sh
#!/bin/bash
a=`ip a show ens33 | grep 192.168.253.111 | wc -l`
if [ $a -eq 0 ];then
	echo "0"
else
	echo "1"
fi
[root@agent1 scripts]#  chmod +x check_backupip.sh

在备份节点添加自定义监控项

[root@agent1 scripts]# vim /etc/zabbix/zabbix_agentd.conf
UnsafeUserParameters=1 UserParameter=check.backup,/scripts/check_backupip.sh
[root@agent1 scripts]# systemctl restart zabbix-agent.service

//在主节点中测试该监控项
[root@server scripts]# yum -y install zabbix-get
[root@server scripts]# zabbix_get -s 192.168.253.130 -k "check.backup"
1

zabbix配置监控项

配置触发器

添加媒介

配置动作

模拟脑裂，关闭主节点的nginx服务

[root@server scripts]# systemctl stop nginx
[root@server scripts]#  systemctl restart keepalived.service