就业班第三阶段（负载均衡） 2401--4.19 day3 nginx3-编程知识

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50advert_int 1authentication {auth_type PASSauth_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backupinterface ens33nopreempt        #设置到back上面，不抢占资源virtual_router_id 80priority 50   #辅助改为50advert_int 1authentication {auth_type PASSauth_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: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00inet 127.0.0.1/8 scope host lovalid_lft forever preferred_lft foreverinet 172.16.147.100/32 scope global lovalid_lft forever preferred_lft foreverinet6 ::1/128 scope host valid_lft forever preferred_lft forever
2: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000link/ether 00:0c:29:ec:8a:fe brd ff:ff:ff:ff:ff:ffinet 172.16.147.155/24 brd 172.16.147.255 scope global noprefixroute dynamic ens33valid_lft 1115sec preferred_lft 1115secinet 172.16.147.101/24 scope global secondary ens33valid_lft forever preferred_lft forever

到此：
可以解决心跳故障keepalived
不能解决Nginx服务故障
4. 扩展对调度器Nginx健康检查（可选）两台都设置
思路：
让Keepalived以一定时间间隔执行一个外部脚本，脚本的功能是当Nginx失败，则关闭本机的Keepalived
(1) script
[root@proxy-master ~]# vim /etc/keepalived/check_nginx_status.sh
#!/bin/bash                                                     
/usr/bin/curl -I http://localhost &>/dev/null   
if [ $? -ne 0 ];then                                            
#   /etc/init.d/keepalived stopsystemctl stop keepalived
fi                                                                      
[root@proxy-master ~]# chmod a+x /etc/keepalived/check_nginx_status.sh

(2). keepalived使用script
! Configuration File for keepalived

global_defs {router_id director1
}
vrrp_script check_nginx {script "/etc/keepalived/check_nginx_status.sh"interval 5
}

vrrp_instance VI_1 {state MASTERinterface ens33virtual_router_id 80priority 100advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {192.168.246.16/24}track_script {check_nginx}
}
注：必须先启动nginx，再启动keepalived

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 MASTERinterface 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50advert_int 1            #检查间隔，默认为1sauthentication {auth_type PASSauth_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 3lb_algo rr     #LVS调度算法lb_kind DR     #LVS集群模式（路由模式）net_mask 255.255.255.0protocol TCP      #健康检查使用的协议real_server 172.16.147.153 80 {weight 1inhibit_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 1inhibit_on_failureTCP_CHECK {connect_timeout 3connect_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 BACKUPinterface ens33nopreempt                    #不抢占资源virtual_router_id 80priority 50advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {172.16.147.101/24}
}
virtual_server 172.16.147.101 80 {delay_loop 3lb_algo rrlb_kind DRnet_mask 255.255.255.0protocol TCPreal_server 172.16.147.153 80 {weight 1inhibit_on_failureTCP_CHECK {connect_port 80connect_timeout 3}}real_server 172.16.147.156 80 {weight 1inhibit_on_failureTCP_CHECK {connect_timeout 3connect_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 keepalived

global_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 keepalived

global_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 MASTERnopreemptinterface 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 ipmcast_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 80priority 100advert_int 1authentication {auth_type PASSauth_pass 1111}virtual_ipaddress {10.3.131.221}# 当前节点成为主节点时触发的脚本 notify_masternotify_master "/etc/keepalived/mail.sh master"# 当前节点转为备节点时触发的脚本 notify_backupnotify_backup "/etc/keepalived/mail.sh backup"# 当前节点转为失败状态时触发的脚本 notify_faultnotify_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 DRnat_mask 255.255.255.0# 会话保持时间persistence_timeout 20# 使用的协议protocol TCPsorry_server 2.2.2.2 80real_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.htmldigest 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;;
esac

2、配置文件

# master配置


! Configuration File for keepalived

global_defs {router_id directory1
}

vrrp_instance VI_1 {state MASTERinterface ens33virtual_router_id 80priority 100advert_int 1authentication {auth_type PASSauth_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 MASTERinterface ens33nopreemptvirtual_router_id 80priority 50advert_int 1authentication {auth_type PASSauth_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