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linux gre keep linux gre keepalive

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1. keepalived简介

1.1 keepalived是什么？
1.2 keepalived的重要功能
1.3 keepalived高可用故障转移的原理
1.4 keepalived原理

1.4.1 keepalived高可用架构图
1.4.2 keepalived工作原理描述

2. keepalived配置文件讲解
3 脑裂

3.1 脑裂产生的原因
3.2 脑裂的常见解决方案
3.3 对脑裂进行监控

4. keepalived实现apache负载均衡机高可用

4.1 keepalived安装

4.1.1 配置主keepalived
4.1.2 配置备keepalived

4.2 在主备机上分别安装apache

4.2.1 在master上安装apache
4.2.2 在slave上安装apache

4.3 keepalived配置

4.3.1 配置主keepalived
4.3.2 配置备keepalived
4.3.3 查看VIP在哪里
4.3.4 访问网页

4.4 修改内核参数，开启监听VIP功能
4.5 让keepalived监控apache负载均衡机
4.6 配置keepalived加入监控脚本的配置

4.6.1 配置主keepalived
4.6.2 配置备keepalived
4.6.3 效果展现

1. keepalived简介

1.1 keepalived是什么？

Keepalived 软件起初是专为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。因此，Keepalived除了能够管理LVS软件外，还可以作为其他服务（例如：Nginx、Haproxy、MySQL等）的高可用解决方案软件。

Keepalived软件主要是通过VRRP协议实现高可用功能的。VRRP是Virtual Router RedundancyProtocol(虚拟路由器冗余协议）的缩写，VRRP出现的目的就是为了解决静态路由单点故障问题的，它能够保证当个别节点宕机时，整个网络可以不间断地运行。

所以，Keepalived 一方面具有配置管理LVS的功能，同时还具有对LVS下面节点进行健康检查的功能，另一方面也可实现系统网络服务的高可用功能。

keepalived官网

1.2 keepalived的重要功能

keepalived 有三个重要的功能，分别是：

管理LVS负载均衡软件
实现LVS集群节点的健康检查
作为系统网络服务的高可用性（failover）

1.3 keepalived高可用故障转移的原理

Keepalived 高可用服务之间的故障切换转移，是通过 VRRP (Virtual Router Redundancy Protocol ,虚拟路由器冗余协议）来实现的。

在 Keepalived 服务正常工作时，主 Master 节点会不断地向备节点发送（多播的方式）心跳消息，用以告诉备 Backup 节点自己还活看，当主 Master 节点发生故障时，就无法发送心跳消息，备节点也就因此无法继续检测到来自主 Master 节点的心跳了，于是调用自身的接管程序，接管主 Master 节点的 IP 资源及服务。而当主 Master 节点恢复时，备 Backup 节点又会释放主节点故障时自身接管的IP资源及服务，恢复到原来的备用角色。

那么，什么是VRRP呢？
VRRP ,全称 Virtual Router Redundancy Protocol ,中文名为虚拟路由冗余协议，VRRP的出现就是为了解决静态踣甶的单点故障问题，VRRP是通过一种竞选机制来将路由的任务交给某台VRRP路由器的。

1.4 keepalived原理

1.4.1 keepalived高可用架构图

1.4.2 keepalived工作原理描述

Keepalived高可用对之间是通过VRRP通信的，因此，我们从 VRRP开始了解起：

VRRP,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。

VRRP是通过一种竟选协议机制来将路由任务交给某台 VRRP路由器的。

VRRP用 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。

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开源。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。

VRRP使用了加密协议加密数据，但Keepalived官方目前还是推荐用明文的方式配置认证类型和密码。

介绍完 VRRP,接下来我再介绍一下 Keepalived服务的工作原理：

Keepalived高可用是通过 VRRP 进行通信的， VRRP是通过竞选机制来确定主备的，主的优先级高于备，因此，工作时主会优先获得所有的资源，备节点处于等待状态，当主挂了的时候，备节点就会接管主节点的资源，然后顶替主节点对外提供服务。

在 Keepalived 服务之间，只有作为主的服务器会一直发送 VRRP 广播包,告诉备它还活着，此时备不会枪占主，当主不可用时，即备监听不到主发送的广播包时，就会启动相关服务接管资源，保证业务的连续性.接管速度最快可以小于1秒。

2. keepalived配置文件讲解

keepalived有三类配置区域，注意不是三种配置文件，是一个配置文件里面三种不同类别的配置区域
全局配置(Global Configuration)
VRRPD配置
LVS配置

global_defs { notification_email { #指定keepalived在发生切换时需要发送email到的对象，一行一个 [email protected] } notification_email_from [email protected] #指定发件人 smtp_server stmp.3evip.cn #指定smtp服务器地址 smtp_connect_timeout 30 #指定smtp连接超时时间 router_id LVS_DEVEL #运行keepalived机器的一个标识 } vrrp_sync_group VG_1{ #监控多个网段的实例 group { inside_network #实例名 outside_network } notify_master /path/xx.sh #指定当切换到master时，执行的脚本 netify_backup /path/xx.sh #指定当切换到backup时，执行的脚本 notify_fault "path/xx.sh VG_1" #故障时执行的脚本 notify /path/xx.sh smtp_alert #使用global_defs中提供的邮件地址和smtp服务器发送邮件通知 } vrrp_instance inside_network { state BACKUP #指定那个为master，那个为backup，如果设置了nopreempt这个值不起作用，主备考priority决定 interface eth0 #设置实例绑定的网卡 dont_track_primary #忽略vrrp的interface错误（默认不设置） track_interface{ #设置额外的监控，里面那个网卡出现问题都会切换 eth0 eth1 } mcast_src_ip #发送多播包的地址，如果不设置默认使用绑定网卡的primary ip garp_master_delay #在切换到master状态后，延迟进行gratuitous ARP请求 virtual_router_id 50 #VPID标记 priority 99 #优先级，高优先级竞选为master advert_int 1 #检查间隔，默认1秒 nopreempt #设置为不抢占注：这个配置只能设置在backup主机上，而且这个主机优先级要比另外一台高 preempt_delay #抢占延时，默认5分钟 debug #debug级别 authentication { #设置认证 auth_type PASS #认证方式 auth_pass 111111 #认证密码 } virtual_ipaddress { #设置vip 192.168.36.200 } } virtual_server 192.168.36.99 80 { delay_loop 6 #健康检查时间间隔 lb_algo rr #lvs调度算法rr|wrr|lc|wlc|lblc|sh|dh lb_kind DR #负载均衡转发规则NAT|DR|RUN persistence_timeout 5 #会话保持时间 protocol TCP #使用的协议 persistence_granularity <NETMASK> #lvs会话保持粒度 virtualhost <string> #检查的web服务器的虚拟主机（host：头） sorry_server<IPADDR> <port> #备用机，所有realserver失效后启用 real_server 192.168.200.5 23 { weight 1 #默认为1,0为失效 inhibit_on_failure #在服务器健康检查失效时，将其设为0，而不是直接从ipvs中删除 notify_up <string> | <quoted-string> #在检测到server up后执行脚本 notify_down <string> | <quoted-string> #在检测到server down后执行脚本 TCP_CHECK { connect_timeout 3 #连接超时时间 nb_get_retry 3 #重连次数 delay_before_retry 3 #重连间隔时间 connect_port 23 健康检查的端口的端口 bindto <ip> } HTTP_GET | SSL_GET{ url{ #检查url，可以指定多个 path / digest <string> #检查后的摘要信息 status_code 200 #检查的返回状态码 } connect_port <port> bindto <IPADD> connect_timeout 5 nb_get_retry 3 delay_before_retry 2 } SMTP_CHECK{ host{ connect_ip <IP ADDRESS> connect_port <port> #默认检查25端口 bindto <IP ADDRESS> } connect_timeout 5 retry 3 delay_before_retry 2 helo_name <string> | <quoted-string> #smtp helo请求命令参数，可选 } MISC_CHECK{ misc_path <string> | <quoted-string> #外部脚本路径 misc_timeout #脚本执行超时时间 misc_dynamic #如设置该项，则退出状态码会用来动态调整服务器的权重，返回0 正常，不修改；返回1，检查失败，权重改为0；返回2-255，正常，权重设置为：返回状态码-2 } } }

3 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、2边“服务”都起不来了；或者2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）

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：
添加冗余的心跳线，例如：双线条线（心跳线也HA），尽量减少“裂脑”发生几率；
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。
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

3.1 脑裂产生的原因

一般来说，脑裂的发生，有以下几种原因：

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

因心跳线坏了（包括断了，老化）
因网卡及相关驱动坏了，ip配置及冲突问题（网卡直连）
因心跳线间连接的设备故障（网卡及交换机）
因仲裁的机器出问题（采用仲裁的方案）

高可用服务器上开启了 iptables防火墙阻挡了心跳消息传输
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
其他服务配置不当等原因，如心跳方式不同，心跳广播冲突、软件Bug等
注意：

Keepalived配置里同一 VRRP实例如果 virtual_router_id两端参数配置不一致也会导致裂脑问题发生。

3.2 脑裂的常见解决方案

在实际生产环境中，我们可以从以下几个方面来防止裂脑问题的发生：

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，这样一条线路坏了，另一个还是好的，依然能传送心跳消息
当检测到裂脑时强行关闭一个心跳节点（这个功能需特殊设备支持，如Stonith、feyce）。相当于备节点接收不到心跳消患，通过单独的线路发送关机命令关闭主节点的电源
做好对裂脑的监控报警（如邮件及手机短信等或值班）.在问题发生时人为第一时间介入仲裁，降低损失。例如，百度的监控报警短信就有上行和下行的区别。报警消息发送到管理员手机上，管理员可以通过手机回复对应数字或简单的字符串操作返回给服务器.让服务器根据指令自动处理相应故障，这样解决故障的时间更短.

当然，在实施高可用方案时，要根据业务实际需求确定是否能容忍这样的损失。对于一般的网站常规业务.这个损失是可容忍的

3.3 对脑裂进行监控

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：

发生了脑裂
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也是会到备上的。

监控脚本如下：

[root@slave ~]# mkdir -p /scripts && cd /scripts [root@slave scripts]# vim check_keepalived.sh #!/bin/bash if [ `ip a show eth0 |grep 192.168.159.250| wc -l` -ne 0 ] then echo "keepalived is error!" else echo "keepalived is OK !" fi

编写脚本时要注意，网卡要改成你自己的网卡名称，VIP也要改成你自己的VIP，最后不要忘了给脚本赋予执行权限，且要修改/scripts目录的属主属组为zabbix

4. keepalived实现apache负载均衡机高可用

环境说明

系统信息

主机名

Centos7

master

192.168.159.137

Centos7

slave

192.168.159.144

本次高可用虚拟IP（VIP）地址暂定为 172.16.159.250

4.1 keepalived安装

4.1.1 配置主keepalived

//关闭防火墙和SELINUX [root@longnian ~]# systemctl status firewalld ● firewalld.service - firewalld - dynamic firewall daemon Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled) Active: inactive (dead) [root@longnian ~]# getenforce Disabled //配置网络源 [root@master yum.repos.d]# curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo [root@master yum.repos.d]# sed -i 's/\$releasever/7/g' /etc/yum.repos.d/CentOS7-Base.repo [root@master yum.repos.d]# wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo [root@master yum.repos.d]# sed -i -e '/mirrors.cloud.aliyuncs.com/d' -e '//d' /etc/yum.repos.d/CentOS-Base.repo //安装一些常用的工具 [root@master ~]# vim wget gcc gcc-c++ //安装keepalived [root@master ~]# yum -y install keepalived //查看安装生成的文件 [root@master ~]# rpm -ql keepalived /etc/keepalived /etc/keepalived/keepalived.conf /etc/sysconfig/keepalived /usr/bin/genhash /usr/lib/systemd/system/keepalived.service /usr/libexec/keepalived /usr/sbin/keepalived /usr/share/doc/keepalived-1.3.5 /usr/share/doc/keepalived-1.3.5/AUTHOR /usr/share/doc/keepalived-1.3.5/CONTRIBUTORS /usr/share/doc/keepalived-1.3.5/COPYING /usr/share/doc/keepalived-1.3.5/ChangeLog /usr/share/doc/keepalived-1.3.5/NOTE_vrrp_vmac.txt /usr/share/doc/keepalived-1.3.5/README /usr/share/doc/keepalived-1.3.5/TODO /usr/share/doc/keepalived-1.3.5/keepalived.conf.SYNOPSIS /usr/share/doc/keepalived-1.3.5/samples /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.HTTP_GET.port /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.IPv6 /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.SMTP_CHECK /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.SSL_GET /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.fwmark /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.inhibit /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.misc_check /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.misc_check_arg /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.quorum /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.sample /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.status_code /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.track_interface /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.virtual_server_group /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.virtualhost /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.vrrp /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.vrrp.localcheck /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.vrrp.lvs_syncd /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.vrrp.routes /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.vrrp.rules /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.vrrp.scripts /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.vrrp.static_ipaddress /usr/share/doc/keepalived-1.3.5/samples/keepalived.conf.vrrp.sync /usr/share/doc/keepalived-1.3.5/samples/ /usr/share/man/man1/genhash.1.gz /usr/share/man/man5/keepalived.conf.5.gz /usr/share/man/man8/keepalived.8.gz /usr/share/snmp/mibs/KEEPALIVED-MIB.txt /usr/share/snmp/mibs/VRRP-MIB.txt /usr/share/snmp/mibs/VRRPv3-MIB.txt

4.1.2 配置备keepalived

//关闭防火墙和SELINUX [root@slave ~]# systemctl status firewalld ● firewalld.service - firewalld - dynamic firewall daemon Loaded: loaded (/usr/lib/systemd/system/firewalld.service; disabled; vendor preset: enabled) Active: inactive (dead) [root@slave ~]# getenforce Disabled //配置网络源 [root@slave yum.repos.d]# curl -o /etc/yum.repos.d/CentOS-Base.repo https://mirrors.aliyun.com/repo/Centos-7.repo [root@slave yum.repos.d]# sed -i 's/\$releasever/7/g' /etc/yum.repos.d/CentOS7-Base.repo [root@slave yum.repos.d]# wget -O /etc/yum.repos.d/epel.repo http://mirrors.aliyun.com/repo/epel-7.repo [root@slave yum.repos.d]# sed -i -e '/mirrors.cloud.aliyuncs.com/d' -e '//d' /etc/yum.repos.d/CentOS-Base.repo //安装keepalived [root@slave ~]# yum -y install keepalived

4.2 在主备机上分别安装apache

4.2.1 在master上安装apache

[root@master ~]# yum -y install httpd [root@master ~]# cd /var/www/html/ [root@master html]# echo "This is master" > /var/www/html/index.html [root@master html]# cat /var/www/html/index.html This is master [root@master html]# systemctl enable --now httpd Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service. [root@master html]# ss -anlt State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::80 :::* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::*

4.2.2 在slave上安装apache

[root@slave ~]# yum -y install httpd [root@slave ~]# cd /var/www/html/ [root@slave html]# echo "This is slave" > /var/www/html/index.html [root@slave html]# cat /var/www/html/index.html This is slave [root@slave ~]# cd /var/www/html/ [root@slave html]# echo "This is slave" > /var/www/html/index.html [root@slave html]# cat /var/www/html/index.html This is slave [root@slave html]# systemctl enable --now httpd Created symlink from /etc/systemd/system/multi-user.target.wants/httpd.service to /usr/lib/systemd/system/httpd.service. [root@slave html]# ss -anlt State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::80 :::* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::*

在浏览器上访问试试，确保master上的apache服务能够正常访问

4.3 keepalived配置

4.3.1 配置主keepalived

//把原来的配置文件备份一下，改为keepalived.conf-bak [root@master keepalived]# ls keepalived.conf keepalived.conf-bak [root@master keepalived]# vim keepalived.conf [root@master keepalived]# cat keepalived.conf ! Configuration File for keepalived global_defs { router_id lb01 } vrrp_instance VI_1 { state MASTER interface eno16777736 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass longnian123. } virtual_ipaddress { 192.168.159.250 } } virtual_server 192.168.159.250 80 { delay_loop 6 lb_algo rr lb_kind DR persistence_timeout 50 protocol TCP real_server 192.168.159.137 80 { weight 1 TCP_CHECK { connect_port 80 connect_timeout 3 nb_get_retry 3 delay_before_retry 3 } } real_server 192.168.159.144 80 { weight 1 TCP_CHECK { connect_port 80 connect_timeout 3 nb_get_retry 3 delay_before_retry 3 } } } [root@master ~]# systemctl enable --now keepalived Created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service. [root@master ~]# systemctl status keepalived ● keepalived.service - LVS and VRRP High Availability Monitor Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled) Active: active (running) since 三 2020-08-05 10:59:27 CST; 23s ago Process: 2371 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS) Main PID: 2372 (keepalived) CGroup: /system.slice/keepalived.service ├─2372 /usr/sbin/keepalived -D ├─2373 /usr/sbin/keepalived -D └─2374 /usr/sbin/keepalived -D 8月 05 10:59:29 master Keepalived_vrrp[2374]: Sending gratuitous ARP on eno1677773...0 8月 05 10:59:29 master Keepalived_vrrp[2374]: Sending gratuitous ARP on eno1677773...0 8月 05 10:59:29 master Keepalived_vrrp[2374]: Sending gratuitous ARP on eno1677773...0 8月 05 10:59:29 master Keepalived_vrrp[2374]: Sending gratuitous ARP on eno1677773...0 8月 05 10:59:34 master Keepalived_vrrp[2374]: Sending gratuitous ARP on eno1677773...0 8月 05 10:59:34 master Keepalived_vrrp[2374]: VRRP_Instance(VI_1) Sending/queueing...0 8月 05 10:59:34 master Keepalived_vrrp[2374]: Sending gratuitous ARP on eno1677773...0 8月 05 10:59:34 master Keepalived_vrrp[2374]: Sending gratuitous ARP on eno1677773...0 8月 05 10:59:34 master Keepalived_vrrp[2374]: Sending gratuitous ARP on eno1677773...0 8月 05 10:59:34 master Keepalived_vrrp[2374]: Sending gratuitous ARP on eno1677773...0 Hint: Some lines were ellipsized, use -l to show in full.

4.3.2 配置备keepalived

//同样把原来的配置文件备份一下，改为keepalived.conf-bak [root@slave keepalived]# ls keepalived.conf keepalived.conf-bak [root@slave keepalived]# vim keepalived.conf [root@slave keepalived]# cat keepalived.conf ! Configuration File for keepalived global_defs { router_id lb02 } vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 80 advert_int 1 authentication { auth_type PASS auth_pass longnian123. } virtual_ipaddress { 192.168.159.250 } } virtual_server 192.168.159.250 80 { delay_loop 6 lb_algo rr lb_kind DR persistence_timeout 50 protocol TCP real_server 192.168.159.137 80 { weight 1 TCP_CHECK { connect_port 80 connect_timeout 3 nb_get_retry 3 delay_before_retry 3 } } real_server 192.168.159.144 80 { weight 1 TCP_CHECK { connect_port 80 connect_timeout 3 nb_get_retry 3 delay_before_retry 3 } } } [root@slave ~]# systemctl enable --now keepalived Created symlink from /etc/systemd/system/multi-user.target.wants/keepalived.service to /usr/lib/systemd/system/keepalived.service. [root@slave ~]# systemctl status keepalived ● keepalived.service - LVS and VRRP High Availability Monitor Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled) Active: active (running) since Wed 2020-08-05 18:59:35 CST; 23s ago Process: 2332 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS) Main PID: 2333 (keepalived) CGroup: /system.slice/keepalived.service ├─2333 /usr/sbin/keepalived -D ├─2334 /usr/sbin/keepalived -D └─2335 /usr/sbin/keepalived -D Aug 05 18:59:35 slave Keepalived_vrrp[2335]: Truncating auth_pass to 8 characters Aug 05 18:59:35 slave Keepalived_vrrp[2335]: VRRP_Instance(VI_1) removing protocol...s. Aug 05 18:59:35 slave Keepalived_vrrp[2335]: Using LinkWatch kernel netlink reflec..... Aug 05 18:59:35 slave Keepalived_vrrp[2335]: VRRP_Instance(VI_1) Entering BACKUP STATE Aug 05 18:59:35 slave Keepalived_vrrp[2335]: VRRP sockpool: [ifindex(2), proto(112...)] Aug 05 18:59:35 slave Keepalived_healthcheckers[2334]: Opening file '/etc/keepalive.... Aug 05 18:59:35 slave Keepalived_healthcheckers[2334]: Unknown keyword 'nb_get_retry' Aug 05 18:59:35 slave Keepalived_healthcheckers[2334]: Unknown keyword 'nb_get_retry' Aug 05 18:59:35 slave Keepalived_healthcheckers[2334]: Activating healthchecker for...0 Aug 05 18:59:35 slave Keepalived_healthcheckers[2334]: Activating healthchecker for...0 Hint: Some lines were ellipsized, use -l to show in full.

4.3.3 查看VIP在哪里

在MASTER上查看

[root@master ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 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: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:b2:1a:0e brd ff:ff:ff:ff:ff:ff inet 192.168.159.137/24 brd 192.168.159.255 scope global dynamic eno16777736 valid_lft 1418sec preferred_lft 1418sec inet 192.168.159.250/32 scope global eno16777736 valid_lft forever preferred_lft forever inet6 fe80::20c:29ff:feb2:1a0e/64 scope link valid_lft forever preferred_lft forever

在SLAVE上查看

[root@slave ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:50:56:23:3e:ef brd ff:ff:ff:ff:ff:ff inet 192.168.159.144/24 brd 192.168.159.255 scope global dynamic eth0 valid_lft 1363sec preferred_lft 1363sec inet6 fe80::250:56ff:fe23:3eef/64 scope link valid_lft forever preferred_lft forever

4.3.4 访问网页

需要关闭备keepalived上的httpd服务之后再访问

4.4 修改内核参数，开启监听VIP功能

此步可做可不做，该功能可用于仅监听VIP的时候
在master上修改内核参数

[root@master ~]# echo 'net.ipv4.ip_nonlocal_bind = 1' >>/etc/sysctl.conf [root@master ~]# sysctl -p net.ipv4.ip_nonlocal_bind = 1 [root@master ~]# cat /proc/sys/net/ipv4/ip_nonlocal_bind 1

在slave上修改内核参数

[root@slave ~]# echo 'net.ipv4.ip_nonlocal_bind = 1' >>/etc/sysctl.conf [root@slave ~]# sysctl -p net.ipv4.ip_nonlocal_bind = 1 [root@slave ~]# cat /proc/sys/net/ipv4/ip_nonlocal_bind 1

4.5 让keepalived监控apache负载均衡机

keepalived通过脚本来监控apache负载均衡机的状态
在master上编写脚本

[root@master ~]# mkdir /scripts [root@master ~]# cd /scripts [root@master scripts]# vim check_httpd.sh [root@master scripts]# cat check_httpd.sh #!/bin/bash httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l) if [ $httpd_status -lt 1 ];then systemctl stop keepalived fi [root@master scripts]# chmod +x check_httpd.sh [root@master scripts]# ll 总用量 4 -rwxr-xr-x 1 root root 142 8月 5 11:22 check_httpd.sh [root@master scripts]# vim notify.sh [root@master scripts]# cat notify.sh #!/bin/bash VIP=$2 case "$1" in master) httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l) if [ $httpd_status -lt 1 ];then systemctl start httpd fi sendmail ;; backup) httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l) if [ $httpd_status -gt 0 ];then systemctl stop httpd fi ;; *) echo "Usage:$0 master|backup VIP" ;; esac [root@master scripts]# chmod +x notify.sh [root@master scripts]# ll 总用量 8 -rwxr-xr-x 1 root root 142 8月 5 11:22 check_httpd.sh -rwxr-xr-x 1 root root 451 8月 5 11:25 notify.sh

在slave上编写脚本

[root@slave ~]# mkdir /scripts [root@slave ~]# cd /scripts [root@slave scripts]# vim notify.sh [root@slave scripts]# cat notify.sh #!/bin/bash VIP=$2 case "$1" in master) httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l) if [ $httpd_status -lt 1 ];then systemctl start httpd fi sendmail ;; backup) httpd_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bhttpd\b'|wc -l) if [ $httpd_status -gt 0 ];then systemctl stop httpd fi ;; *) echo "Usage:$0 master|backup VIP" ;; esac [root@slave scripts]# chmod +x notify.sh [root@slave scripts]# ll total 4 -rwxr-xr-x 1 root root 451 Aug 5 19:28 notify.sh

此处的脚本名称应避免与服务名相同，推荐用服务名的首字母代替，如check_n，不要给脚本起名check_httpd，我这里因为脚本里写了grep|$0，所以已经把脚本本身的这个过滤掉了，所以不影响

4.6 配置keepalived加入监控脚本的配置

4.6.1 配置主keepalived

[root@master ~]# vim /etc/keepalived/keepalived.conf [root@master ~]# cat /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { router_id lb01 } vrrp_script httpd_check { //添加这四行 script "/scripts/check_httpd.sh" interval 1 weight -30 } vrrp_instance VI_1 { state BACKUP interface eno16777736 virtual_router_id 51 priority 100 advert_int 1 authentication { auth_type PASS auth_pass longnian123. } virtual_ipaddress { 192.168.159.250 } track_script { //添加这五行 httpd_check } notify_master "/scripts/notify.sh master 192.168.159.250" notify_backup "/scripts/notify.sh backup 192.168.159.250" ................ [root@master ~]# systemctl restart keepalived

4.6.2 配置备keepalived

backup无需检测httpd是否正常，当升级为MASTER时启动httpd，当降级为BACKUP时关闭

[root@slave ~]# vim /etc/keepalived/keepalived.conf [root@slave ~]# cat /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { router_id lb02 } } vrrp_instance VI_1 { state BACKUP interface eth0 virtual_router_id 51 priority 80 advert_int 1 authentication { auth_type PASS auth_pass longnian123. } virtual_ipaddress { 192.168.159.250 } track_script { //添加这五行 httpd_check } notify_master "/scripts/notify.sh master 192.168.159.250" notify_backup "/scripts/notify.sh backup 192.168.159.250" ................ [root@slave ~]# systemctl restart keepalived

4.6.3 效果展现

关闭主keepalived上的httpd服务，查看本机IP和备keepalived的IP

[root@master ~]# systemctl stop httpd [root@master ~]# ss -anlt State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::* [root@master ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 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: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:b2:1a:0e brd ff:ff:ff:ff:ff:ff inet 192.168.159.137/24 brd 192.168.159.255 scope global dynamic eno16777736 valid_lft 1024sec preferred_lft 1024sec inet6 fe80::20c:29ff:feb2:1a0e/64 scope link valid_lft forever preferred_lft forever //查看备keepalived的IP [root@slave ~]# ss -anlt State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::80 :::* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::* [root@slave ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:50:56:23:3e:ef brd ff:ff:ff:ff:ff:ff inet 192.168.159.144/24 brd 192.168.159.255 scope global dynamic eth0 valid_lft 1544sec preferred_lft 1544sec inet 192.168.159.250/32 scope global eth0 valid_lft forever preferred_lft forever inet6 fe80::250:56ff:fe23:3eef/64 scope link valid_lft forever preferred_lft forever

关闭备keepalived上的keepalived服务，让IP重回到主keepalived上，利用脚本实现效果

//关闭主keepalived上的httpd服务，可以看到keepalived服务也通过脚本自动关闭了 [root@master ~]# ss -anlt State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::80 :::* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::* [root@master ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 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: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:b2:1a:0e brd ff:ff:ff:ff:ff:ff inet 192.168.159.137/24 brd 192.168.159.255 scope global dynamic eno16777736 valid_lft 1313sec preferred_lft 1313sec inet 192.168.159.250/32 scope global eno16777736 valid_lft forever preferred_lft forever inet6 fe80::20c:29ff:feb2:1a0e/64 scope link valid_lft forever preferred_lft forever [root@master ~]# systemctl stop httpd [root@master ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 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: eno16777736: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:0c:29:b2:1a:0e brd ff:ff:ff:ff:ff:ff inet 192.168.159.137/24 brd 192.168.159.255 scope global dynamic eno16777736 valid_lft 1303sec preferred_lft 1303sec inet6 fe80::20c:29ff:feb2:1a0e/64 scope link valid_lft forever preferred_lft forever [root@master ~]# systemctl status keepalived ● keepalived.service - LVS and VRRP High Availability Monitor Loaded: loaded (/usr/lib/systemd/system/keepalived.service; enabled; vendor preset: disabled) Active: inactive (dead) since 三 2020-08-05 11:57:25 CST; 12s ago Process: 12657 ExecStart=/usr/sbin/keepalived $KEEPALIVED_OPTIONS (code=exited, status=0/SUCCESS) Main PID: 12658 (code=exited, status=0/SUCCESS) CGroup: /system.slice/keepalived.service 8月 05 11:56:03 master Keepalived_healthcheckers[12659]: TCP connection to [192.168... 8月 05 11:56:06 master Keepalived_healthcheckers[12659]: TCP connection to [192.168... 8月 05 11:56:06 master Keepalived_healthcheckers[12659]: Check on service [192.168.... 8月 05 11:56:06 master Keepalived_healthcheckers[12659]: Removing service [192.168.... 8月 05 11:57:24 master Keepalived_healthcheckers[12659]: TCP connection to [192.168... 8月 05 11:57:24 master Keepalived[12658]: Stopping 8月 05 11:57:24 master systemd[1]: Stopping LVS and VRRP High Availability Monitor... 8月 05 11:57:24 master Keepalived_vrrp[12660]: VRRP_Instance(VI_1) sent 0 priority 8月 05 11:57:24 master Keepalived_vrrp[12660]: VRRP_Instance(VI_1) removing protoc.... 8月 05 11:57:25 master systemd[1]: Stopped LVS and VRRP High Availability Monitor. Hint: Some lines were ellipsized, use -l to show in full. //查看备keepalived上有没有IP，httpd服务有没有自动启动 [root@slave ~]# ss -anlt State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::* [root@slave ~]# ip a 1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN 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: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000 link/ether 00:50:56:23:3e:ef brd ff:ff:ff:ff:ff:ff inet 192.168.159.144/24 brd 192.168.159.255 scope global dynamic eth0 valid_lft 1267sec preferred_lft 1267sec inet 192.168.159.250/32 scope global eth0 valid_lft forever preferred_lft forever inet6 fe80::250:56ff:fe23:3eef/64 scope link valid_lft forever preferred_lft forever [root@slave ~]# ss -anlt State Recv-Q Send-Q Local Address:Port Peer Address:Port LISTEN 0 128 *:22 *:* LISTEN 0 100 127.0.0.1:25 *:* LISTEN 0 128 :::80 :::* LISTEN 0 128 :::22 :::* LISTEN 0 100 ::1:25 :::*

作者：酷小年

-------------------------------------------

个性签名：独学而无友，则孤陋而寡闻。做一个灵魂有趣的人！

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