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就业班 第三阶段（负载均衡） 2401--4.19 day3
二、企业 keepalived 高可用项目实战
1、Keepalived VRRP 介绍
keepalived是什么 keepalived是集群管理中保证集群高可用的一个服务软件，用来防止单点故障。 keepalived工作原理 keepalived是以VRRP协议为实现基础的，VRRP全称Virtual Router Redundancy Protocol，即虚拟路由冗余协议。 虚拟路由冗余协议，可以认为是实现路由器高可用的协议，即将N台提供相同功能的路由器组成一个路由器组，这个组里面有一个master和多个backup，master上面有一个对外提供服务的vip（该路由器所在局域网内其他机器的默认路由为该vip），master会发组播，当backup收不到vrrp包时就认为master宕掉了，这时就需要根据VRRP的优先级来选举一个backup当master。这样的话就可以保证路由器的高可用了。 keepalived主要有三个模块，分别是core、check和vrrp。core模块为keepalived的核心，负责主进程的启动、维护以及全局配置文件的加载和解析。check负责健康检查，包括常见的各种检查方式。vrrp模块是来实现VRRP协议的。 ============================================== 脑裂 split barin： Keepalived的BACKUP主机在收到不MASTER主机报文后就会切换成为master，如果是它们之间的通信线路出现问题，无法接收到彼此的组播通知，但是两个节点实际都处于正常工作状态，这时两个节点均为master强行绑定虚拟IP，导致不可预料的后果，这就是脑裂。 解决方式: 1、添加更多的检测手段，比如冗余的心跳线（两块网卡做健康监测），ping对方等等。尽量减少"裂脑"发生机会。(指标不治本，只是提高了检测到的概率)； 2、设置仲裁机制。两方都不可靠，那就依赖第三方。比如启用共享磁盘锁，ping网关等。(针对不同的手段还需具体分析)； 3、爆头，将master停掉。然后检查机器之间的防火墙。网络之间的通信
2、Nginx+keepalived实现七层的负载均衡
Nginx通过Upstream模块实现负载均衡
upstream 支持的负载均衡算法
主机清单：
主机名 ip 系统 用途 Proxy-master 172.16.147.155 centos7.5 主负载 Proxy-slave 172.16.147.156 centos7.5 主备 Real-server1 172.16.147.153 Centos7.5 web1 Real-server2 172.16.147.154 centos7.5 Web2 Vip for proxy 172.16.147.100 配置安装nginx 所有的机器，关闭防火墙和selinux [root@proxy-master ~]# systemctl stop firewalld //关闭防火墙 [root@proxy-master ~]# sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/sysconfig/selinux //关闭selinux，重启生效 [root@proxy-master ~]# setenforce 0 //关闭selinux，临时生效 安装nginx， 全部4台 [root@proxy-master ~]# cd /etc/yum.repos.d/ [root@proxy-master yum.repos.d]# vim nginx.repo [nginx-stable] name=nginx stable repo baseurl=http://nginx.org/packages/centos/$releasever/$basearch/ gpgcheck=0 enabled=1 [root@proxy-master yum.repos.d]# yum install yum-utils -y [root@proxy-master yum.repos.d]# yum install nginx -y
一、实施过程 1、选择两台nginx服务器作为代理服务器。 2、给两台代理服务器安装keepalived制作高可用生成VIP 3、配置nginx的负载均衡 # 两台配置完全一样 [root@proxy-master ~]# vim /etc/nginx/nginx.conf user nginx; worker_processes auto; error_log /var/log/nginx/error.log; pid /run/nginx.pid; include /usr/share/nginx/modules/*.conf; events { worker_connections 1024; } http { log_format main '$remote_addr - $remote_user [$time_local] "$request" ' '$status $body_bytes_sent "$http_referer" ' '"$http_user_agent" "$http_x_forwarded_for"'; access_log /var/log/nginx/access.log main; sendfile on; tcp_nopush on; tcp_nodelay on; keepalive_timeout 65; types_hash_max_size 2048; include /etc/nginx/mime.types; default_type application/octet-stream; include /etc/nginx/conf.d/*.conf; upstream backend { server 172.16.147.154:80 weight=1 max_fails=3 fail_timeout=20s; server 172.16.147.153:80 weight=1 max_fails=3 fail_timeout=20s; } server { listen 80; server_name localhost; location / { proxy_pass http://backend; proxy_set_header Host $host:$proxy_port; proxy_set_header X-Forwarded-For $remote_addr; } } }Keepalived实现调度器HA
注：主/备调度器均能够实现正常调度 1. 主/备调度器安装软件 [root@proxy-master ~]# yum install -y keepalived [root@proxy-slave ~]# yum install -y keepalived [root@proxy-master ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak [root@proxy-master ~]# vim /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { router_id directory1 #辅助改为directory2 } vrrp_instance VI_1 { state MASTER #定义主还是备 interface ens33 #VIP绑定接口 virtual_router_id 80 #整个集群的调度器一致 priority 100 #back改为50 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 172.16.147.100/24 # vip } } [root@proxy-slave ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak [root@proxy-slave ~]# vim /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { router_id directory2 } vrrp_instance VI_1 { state BACKUP #设置为backup interface ens33 nopreempt #设置到back上面，不抢占资源 virtual_router_id 80 priority 50 #辅助改为50 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 172.16.147.100/24 } } 3. 启动KeepAlived（主备均启动） [root@proxy-master ~]# systemctl enable keepalived [root@proxy-slave ~]# systemctl start keepalived [root@proxy-master ~]# ip a 1: lo:3、LVS_Director + KeepAlived
主机名 ip 系统 用途 client 172.16.147.1 mac 客户端 lvs-keepalived-master 172.16.147.154 centos7.5 分发器 lvs-keepalived-slave 172.16.147.155 centos7.5 分发器备 test-nginx1 172.16.147.153 centos7.5 web1 test-nginx2 172.16.147.156 centos7.5 web2 vip 172.16/147.101 LVS_Director + KeepAlived KeepAlived在该项目中的功能： 1. 管理IPVS的路由表（包括对RealServer做健康检查） 2. 实现调度器的HA http://www.keepalived.org Keepalived所执行的外部脚本命令建议使用绝对路径 实施步骤： 1. 主/备调度器安装软件 [root@lvs-keepalived-master ~]# yum -y install ipvsadm keepalived [root@lvs-keepalived-slave ~]# yum -y install ipvsadm keepalived 2. Keepalived lvs-master [root@lvs-keepalived-master ~]# vim /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { router_id lvs-keepalived-master #辅助改为lvs-backup } vrrp_instance VI_1 { state MASTER interface ens33 #VIP绑定接口 virtual_router_id 80 #VRID 同一组集群，主备一致 priority 100 #本节点优先级，辅助改为50 advert_int 1 #检查间隔，默认为1s authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 172.16.147.101/24 # 可以写多个vip } } virtual_server 172.16.147.101 80 { #LVS配置 delay_loop 3 lb_algo rr #LVS调度算法 lb_kind DR #LVS集群模式（路由模式） net_mask 255.255.255.0 protocol TCP #健康检查使用的协议 real_server 172.16.147.153 80 { weight 1 inhibit_on_failure #当该节点失败时，把权重设置为0，而不是从IPVS中删除 TCP_CHECK { #健康检查 connect_port 80 #检查的端口 connect_timeout 3 #连接超时的时间 } } real_server 172.16.147.156 80 { weight 1 inhibit_on_failure TCP_CHECK { connect_timeout 3 connect_port 80 } } } [root@lvs-keepalived-slave ~]# vim /etc/keepalived/keepalived.conf ! Configuration File for keepalived global_defs { router_id lvs-keepalived-slave } vrrp_instance VI_1 { state BACKUP interface ens33 nopreempt #不抢占资源 virtual_router_id 80 priority 50 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 172.16.147.101/24 } } virtual_server 172.16.147.101 80 { delay_loop 3 lb_algo rr lb_kind DR net_mask 255.255.255.0 protocol TCP real_server 172.16.147.153 80 { weight 1 inhibit_on_failure TCP_CHECK { connect_port 80 connect_timeout 3 } } real_server 172.16.147.156 80 { weight 1 inhibit_on_failure TCP_CHECK { connect_timeout 3 connect_port 80 } } } 3. 启动KeepAlived（主备均启动） [root@lvs-keepalived-master ~]# systemctl start keepalived [root@lvs-keepalived-master ~]# systemctl enable keepalived [root@lvs-keepalived-master ~]# ipvsadm -Ln IP Virtual Server version 1.2.1 (size=4096) Prot LocalAddress:Port Scheduler Flags -> RemoteAddress:Port Forward Weight ActiveConn InActConn TCP 172.16.147.101:80 rr persistent 20 -> 172.16.147.153:80 Route 1 0 0 -> 172.16.147.156:80 Route 0 0 0 4. 所有RS配置(nginx1,nginx2) 配置好网站服务器，测试所有RS [root@test-nginx1 ~]# yum install -y nginx [root@test-nginx2 ~]# yum install -y nginx [root@test-nginx1 ~]# echo "ip addr add dev lo 172.16.147.101/32" >> /etc/rc.local [root@test-nginx1 ~]# echo "net.ipv4.conf.all.arp_ignore = 1" >> /etc/sysctl.conf [root@test-nginx1 ~]# echo "net.ipv4.conf.all.arp_announce = 2" >> /etc/sysctl.conf [root@test-nginx1 ~]# sysctl -p [root@test-nginx1 ~]# echo "web1..." >> /usr/share/nginx/html/index.html [root@test-nginx1 ~]# systemctl start nginx [root@test-nginx1 ~]# chmod +x /etc/rc.local LB集群测试 所有分发器和Real Server都正常 主分发器故障及恢复MySQL+Keepalived
Keepalived+mysql 自动切换
项目环境：
VIP 192.168.246.100
mysql1 192.168.246.162 keepalived-master
mysql2 192.168.246.163 keepalived-salve一、mysql 主主同步 （不使用共享存储，数据保存本地存储）
二、安装keepalived
三、keepalived 主备配置文件
四、mysql状态检测脚本/root/bin/keepalived_check_mysql.sh
五、测试及诊断
实施步骤：
一、mysql 主主同步
二、安装keepalived---两台机器都操作
[root@mysql-keepalived-master ~]# yum -y install keepalived
[root@mysql-keepalived-slave ~]# yum -y install keepalived
三、keepalived 主备配置文件
192.168.246.162 master配置
[root@mysql-keepalived-master ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@mysql-keepalived-master ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalivedglobal_defs {
router_id master
}
vrrp_script check_run {
script "/etc/keepalived/keepalived_chech_mysql.sh"
interval 5
}vrrp_instance VI_1 {
state MASTER
interface ens33
virtual_router_id 89
priority 100
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.246.100/24
}
track_script {
check_run
}
}
slave 192.168.246.163 配置
[root@mysql-keepalived-slave ~]# cp /etc/keepalived/keepalived.conf /etc/keepalived/keepalived.conf.bak
[root@mysql-keepalived-slave ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalivedglobal_defs {
router_id backup
}
vrrp_script check_run {
script "/etc/keepalived/keepalived_check_mysql.sh"
interval 5
}vrrp_instance VI_1 {
state BACKUP
nopreempt
interface ens33
virtual_router_id 89
priority 50
advert_int 1
authentication {
auth_type PASS
auth_pass 1111
}
virtual_ipaddress {
192.168.246.100/24
}
track_script {
check_run
}
}
四、mysql状态检测脚本/root/keepalived_check_mysql.sh（两台MySQL同样的脚本）
版本一：简单使用：
[root@mysql-keepalived-master ~]# vim /etc/keepalived/keepalived_check_mysql.sh
#!/bin/bash
/usr/bin/mysql -uroot -p'QianFeng@2019!' -e "show status" &>/dev/null
if [ $? -ne 0 ] ;then
# service keepalived stop
systemctl stop keepalived
fi
[root@mysql-keepalived-master ~]# chmod +x /etc/keepalived/keepalived_check_mysql.sh
==========================================================================
两边均启动keepalived
方式一:
[root@mysql-keepalived-master ~]# systemctl start keepalived
[root@mysql-keepalived-master ~]# systemctl enable keepalived
方式二:
# /etc/init.d/keepalived start
# /etc/init.d/keepalived start
# chkconfig --add keepalived
# chkconfig keepalived on
注意:在任意一台机器作为客户端。在测试的时候记得检查mysql用户的可不可以远程登录。补充
keepalived 配置lvs
! Configuration File for keepalived global_defs { router_id lvs-master } vrrp_instance VI_1 { state MASTER nopreempt interface em1 # 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 mcast_src_ip 10.3.131.50 # unicast src ip 如果两节点的上联交换机禁用了组播，则只能采用vrrp单播通告的方式 # unicast_src_ip xx.xx.xx.xx # unicast_peer { # xx.xx.xx.xx # } virtual_router_id 80 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 10.3.131.221 } # 当前节点成为主节点时触发的脚本 notify_master notify_master "/etc/keepalived/mail.sh master" # 当前节点转为备节点时触发的脚本 notify_backup notify_backup "/etc/keepalived/mail.sh backup" # 当前节点转为失败状态时触发的脚本 notify_fault notify_fault "/etc/keepalived/mail.sh fault" } virtual_server 10.3.131.221 80 { # 健康检查时间间隔，小于6秒 delay_loop 6 # 轮询算法 lb_algo rr # lvs 模式 lb_kind DR nat_mask 255.255.255.0 # 会话保持时间 persistence_timeout 20 # 使用的协议 protocol TCP sorry_server 2.2.2.2 80 real_server 10.3.131.30 80 { # 权重 weight 1 # 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 inhibit_on_failure #在检测到server up后执行脚本 notify_up /etc/keepalived/start.sh start #在检测到server down后执行脚本 notify_down /etc/keepalived/start.sh shutdown # 采用url方式检查 HTTP_GET { url { path /index.html digest 481bf8243931326614960bdc17f99b00 } # 检测端口 connect_port 80 # 连接超时时间 connect_timeout 3 # 重试次数 nb_get_retry 3 # 重连间隔时间 delay_before_retry 2 } } } 检查方式: HTTP_GET URL检查 TCP_GET 端口检查节点配置
keepalived 自带通知组件并不是很友好，这里我们采用自定义邮件通知方式
1、shell 邮件告警
# yum install -y mailx # vim /etc/mail.rc set from=newrain_wang@163.com set smtp=smtp.163.com set smtp-auth-user=newrain_wang@163.com set smtp-auth-password=XXXXXXXXXXXXXX set smtp-auth=login set ssl-verify=ignore # 脚本代码 #!/bin/bash to_email='1161733918@qq.com' ipaddress=`ip -4 a show dev ens33 | awk '/brd/{print $2}'` notify() { mailsubject="${ipaddress}to be $1, vip转移" mailbody="$(date +'%F %T'): vrrp 飘移, $(hostname) 切换到 $1" echo "$mailbody" | mail -s "$mailsubject" $to_email } case $1 in master) notify master ;; backup) notify backup ;; fault) notify fault ;; *) echo "Usage: $(basename $0) {master|backup|fault}" exit 1 ;; esac2、配置文件
# master配置 ! Configuration File for keepalived global_defs { router_id directory1 } vrrp_instance VI_1 { state MASTER interface ens33 virtual_router_id 80 priority 100 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.96.100/24 } notify_master "/etc/keepalived/script/sendmail.sh master" notify_backup "/etc/keepalived/script/sendmail.sh backup" notify_fault "/etc/keepalived/script/sendmail.sh fault" } # 解释： #当前节点成为主节点时触发的脚本 notify_master #当前节点转为备节点时触发的脚本 notify_backup #当前节点转为失败状态时触发的脚本 notify_fault #back配置 ! Configuration File for keepalived global_defs { router_id directory2 } vrrp_instance VI_1 { state MASTER interface ens33 nopreempt virtual_router_id 80 priority 50 advert_int 1 authentication { auth_type PASS auth_pass 1111 } virtual_ipaddress { 192.168.91.134/24 } notify_master "/etc/keepalived/notify.sh master" notify_backup "/etc/keepalived/notify.sh backup" notify_fault "/etc/keepalived/notify.sh fault" }自己总结的：
两个负载均衡器
master backup
master down掉，backup上
master发组播
如果虚拟机版本是7.7 ，需要systemctl kill keepalived
实例 间隔时间 验证
配置好了之后，master那台机子有VIP，backup没有，这是正常的，因为master没有down掉
写一个小代码，让keepalived和nginx关联起来，在master中写
写到配置文件global下面，这个间隔时间要比master组播的间隔时间要长一点
vrrp_script check{
script "/etc/keepalived/script/nginx_check.sh"
interval 2
}
测试：确保nginx是开着的，不然ip飘逸不过去
测试结果：
·
格式一定要标准，脚本写了之后不需要重启
keepalived 配置lvs
master error real-server1 real-server2
在master机子配置 keepalived
并添加一个ip或者一个网卡
其他三台机子需要配置唯一ip
ip a a 192.168.91.134/32 dev lo
当dr要接受消息时候让rs保持静默
在其他三台机子：
[root@real-server1 ~]# ip addr add dev lo 172.16.147.200/32 #在lo接口上绑定VIP [root@real-server1 ~]# echo 1 > /proc/sys/net/ipv4/conf/all/arp_ignore #忽略arp广播 [root@real-server1 ~]# echo 2 > /proc/sys/net/ipv4/conf/all/arp_announce #匹配精确ip地址回包
并且下载并启动nginx服务，写好自己要测试的三个页面（每台一个）
并测试
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- 原文地址：https://blog.csdn.net/weixin_50382197/article/details/137976328