linux运维、架构之路-keepalived高可用
一、Keepalived介绍
Keepalived起初是专为LVS负载均衡软件设计的,用来管理并监控LVS集群系统中各个服务节点的状态,后来又加入了可以实现高可用的VRRP功能,Keepalived是一款高可用软件,它的功能主要包括:
1、管理LVS负载均衡软件
2、实现对LVS集群节点健康检查功能
3、作为系统网络服务的高可用功能
二、Keepalived工作原理
Keepalived的实现基于VRRP
1、VRRP协议,全称Virtual Router Redundancy Protocol,中文名为虚拟路由冗余协议,VRRP的出现是为了解决静态路由的单点故障。
2、VRRP是用过IP多播的方式(默认多播地址(224.0.0.18))实现高可用对之间通信的。
3、工作时主节点发包,备节点接包,当备节点接收不到主节点发的数据包的时候,就启动接管程序接管主节点的资源。备节点可以有多个,通过优先级竞选,但一般Keepalived系统运维工作中都是一对
三、keepalived部署
1、安装keepalived(lb01 lb02)
rpm -qa keepalived
yum install keepalived -y
2、keepalived配置文件详解
global_defs { --- 全局配置标题
notification_email { --- 定义管理员邮箱信息,
330882721@qq.com
330442721@qq.com
}
notification_email_from oldboy@163.com --- 定义利用什么邮箱发送邮件
smtp_server smtp.163.com --- 定义邮件服务器信息
smtp_connect_timeout 30 --- 定义邮件发送超时时间
router_id oldboy01 --- (重点参数)局域网keepalived主机身份标识信息,每一个keepalived主机身份标识信息唯一
}
vrrp_instance VI_1 { --- vrrp协议相关配置(vip地址设置)
state MASTER --- keepalived角色描述(状态)信息,可以配置参数(MASTER BACKUP)
interface eth0 --- 表示将生成虚IP地址,设置在指定的网卡上
virtual_router_id 51 --- 表示keepalived家族标识信息
priority 100 --- keepalived服务竞选主备服务器优先级设置(越大越优先)
advert_int 1 --- 主服务组播包发送间隔时间
authentication { --- 主备主机之间通讯认证机制,
auth_type PASS --- 采用明文认证机制
auth_pass 1111 --- 编写明文密码
}
virtual_ipaddress { --- 设置虚拟IP地址信息
10.0.0.3
}
}
3、搭建基础的keepalived配置文件
#lb01主 global_defs { router_id LVS_01 }
vrrp_instance VI_1 { state MASTER interface eth0 virtual_router_id 51 priority 150 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.0.0.3/24 dev eth0 label eth0:1 } } 虚拟IP地址显示信息: |
#lb02备 global_defs { router_id LVS_02 }
vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.0.0.3/24 dev eth0 label eth0:1 } } 虚拟IP地址显示信息: |
测试说明:进行抓包观察配置效果;并且对比两个负载均衡服务器的配置文件
四、keepaliver裂脑
裂脑产生的原因
①高可用服务器之间心跳线链路发生故障,导致无法正常通信,心跳线坏了(包括断了,老化)
②网卡及相关驱动坏了,IP配置及冲突问题(网上直连)
③心跳线间连接的设置故障(网上及交换机)
④高可用服务器上开启了iptables防火墙阻挡了心跳消息传输
⑤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
解决裂脑常见方案
①同时使用串行电缆和以太网电缆连接,同时用两条心跳线路
②当检测裂脑时强行关闭一个心跳节点(这个功能需要特殊设备支持,如stonith、fence)
③运维层面做好对裂脑的监控报警
#制作监控脚本---lb02
报警的条件:只要lb02 上面有vip
1.lb01 挂了
2.心碎
#!/bin/bash
#desc: jiankong lb02 vip
if [ `ip a s eth0 |grep -c "10.0.0.3"` == 1 ];then
echo "baojing"
fi
五、企业实践案例一:nginx反向代理只监听vip地址,防攻击
1、企业keepalived服务应用(修改nginx反向代理只监听vip地址)
#lb01 lb02 nginx配置
worker_processes 1; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; sendfile on; keepalive_timeout 65; log_format main '$remote_addr - $remote_user [$time_local] "$request" ' '$status $body_bytes_sent "$http_referer" ' '"$http_user_agent" "$http_x_forwarded_for"'; upstream server_pools { server 10.0.0.7; server 10.0.0.8; server 10.0.0.9; } server { listen 10.0.0.3:80; server_name www.etiantian.org; location / { proxy_pass http://server_pools; proxy_set_header Host $host; proxy_set_header X-Forwarded-For $remote_addr; } access_log logs/access_www.log main; } server { listen 10.0.0.3:80; server_name blog.etiantian.org; location / { proxy_pass http://server_pools; proxy_set_header Host $host; proxy_set_header X-Forwarded-For $remote_addr; } access_log logs/access_blog.log main; } }
说明:在修改反向代理服务器配置文件监听地址时,多个server都需要配置监听地址,否则仍旧使用默认监听所有,nginx修改ip相关的必须重启服务,平滑重启不启作用
2、lb02上不存在vip地址,无法监听,需要修改内核文件
解决方法:
echo 'net.ipv4.ip_nonlocal_bind = 1' >>/etc/sysctl.conf
sysctl -p
六、企业实践案例二:keepalived结合脚本监控nginx服务
1、nginx服务停止,keepalived服务自动停止,vip飘走
#!/bin/bash #name: check_web.sh #desc: check nginx and kill keepalived if [ `ps -ef |grep nginx |grep -v grep |wc -l` -lt 2 ];then /etc/init.d/keepalived stop fi
2、把监控脚本放入keepalived配置文件中
global_defs { router_id LVS_02 } vrrp_script check_web { script "/server/scripts/check_web.sh" --- 表示将一个脚本信息赋值给变量check_web interval 2 --- 执行监控脚本的间隔时间 weight 2 --- 利用权重值和优先级进行运算,从而降低主服务优先级 使之变为备服务器(建议先忽略) } vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.0.0.3/24 dev eth0 label eth0:1 } track_script { check_web } }
七、企业实践案例三:keepalived多实例配置
#lb01
global_defs { router_id LVS_01 } vrrp_instance VI_1 { state MASTER interface eth0 virtual_router_id 51 priority 150 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.0.0.3/24 dev eth0 label eth0:1 } } vrrp_instance VI_2 { state BACKUP interface eth0 virtual_router_id 52 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.0.0.4/24 dev eth0 label eth0:2 } }
#lb02 global_defs { router_id LVS_02 } vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.0.0.3/24 dev eth0 label eth0:1 } } vrrp_instance VI_2 { state MASTER interface eth0 virtual_router_id 52 priority 150 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.0.0.4/24 dev eth0 label eth0:2 } }
#lb01 lb02 nginx.conf worker_processes 1; events { worker_connections 1024; } http { include mime.types; default_type application/octet-stream; sendfile on; keepalive_timeout 65; log_format main '$remote_addr - $remote_user [$time_local] "$request" ' '$status $body_bytes_sent "$http_referer" ' '"$http_user_agent" "$http_x_forwarded_for"'; upstream server_pools { server 10.0.0.7; server 10.0.0.8; server 10.0.0.9; } server { listen 10.0.0.3:80; server_name www.etiantian.org; location / { proxy_pass http://server_pools; proxy_set_header Host $host; proxy_set_header X-Forwarded-For $remote_addr; } access_log logs/access_www.log main; } server { listen 10.0.0.4:80; server_name blog.etiantian.org; location / { proxy_pass http://server_pools; proxy_set_header Host $host; proxy_set_header X-Forwarded-For $remote_addr; } access_log logs/access_blog.log main; } }
windows hosts解析
10.0.0.3 www.etiantian.org 10.0.0.4 bbs.etiantian.org
八、指定文件接收Keepalived服务日志
vi /etc/sysconfig/keepalived
KEEPALIVED_OPTIONS="-D -S 0 -d"
vi /etc/rsyslog.conf
local0.* /var/log/keepalived.log
/etc/init.d/keepalived restart
查看生成的接收keepalived日志文件
ll /var/log/keepalived.log
-rw------- 1 root root 5600 Oct 13 11:43 /var/log/keepalived.log