[高可用web服务器集群]Nginx/高可用服务器搭建

负载均衡简述
负载平衡（Load balancing）是一种计算机网络技术，用来在多个计算机（计算机集群）、网络连接、CPU、磁碟驱动器或其他资源中分配负载，以达到最佳化资源使用、最大化吞吐率、最小化响应时间、同时避免过载的目的。
使用带有负载平衡的多个伺服器组件，取代单一的组件，可以通过冗余提高可靠性。负载平衡服务通常是由专用软體和硬體来完成。
keepalived简述
Keepalived的作用是检测服务器的状态，如果有一台web服务器死机，或工作出现故障，Keepalived将检测到，并将有故障的服务器从系统中剔除，同时使用其他服务器代替该服务器的工作，当服务器工作正常后Keepalived自动将服务器加入到服务器群中，这些工作全部自动完成，不需要人工干涉，需要人工做的只是修复故障的服务器。

高可用服务器0：

hostname highAvailableServer0
yum -y update
yum -y install epel-release

#nginx配置 反向代理+负载均衡配置
yum -y install nginx
vim /etc/nginx/nginx.conf
##http下面添加cache保存目录
http{
	proxy_cache_path /tmp/nginx/cache levels=1:2 keys_zone=STATIC:10m inactive=24h max_size=50m;
}
##添加upstream服务器组
upstream webCluster{
	server 172.16.1.30;
	server 172.16.1.31;
	server 127.0.0.1:8080 backup;
}
##反向代理web服务器集群
server {
	listen 80;
	location / {
		proxy_pass http://webCluster/;
		proxy_connect_timeout 1;
		proxy_read_timeout 1;
		proxy_send_timeout 1;
		proxy_cache STATIC;
		proxy_cache_valid 200 1d;
	}
}
##定义错误显示服务器
server {
	listen 8080;
	root /web/error/;
	index index.html;
}
systemctl enable nginx
systemctl start nginx

#keepalived配置
yum -y install keepalived配置
##配置keepalived.conf
cat > /etc/keepalived/keepalived.conf << EOF
! Configuration File for keepalived

global_defs {
	router_id NodeA
}
vrrp_script check_nginx{
	script "/root/check_nginx.sh"
	interval 2
	weight 2
}
vrrp_instance VI_1 {
	state MASTER
	interface eno33554960
	virtual_router_id 51
	priority 101
	advert_int 1
	authentication {
		auth_tyoe proxy_pass
		auth_pass 1234
	}
	virtual_uoaddress {
		8.8.8.8/24 dev ens37
	}
	track_script {
		check_nginx
	}
}
EOF
#监控nginx脚本吗
cat > /root/check_nginx.sh << EOF
#!/bin/bash
if ["$(ps -ef | grep "nginx: master process" | grep -v grep)" == ""]
then
/usr/sbin/nginx
sleep 5
if ["$(ps -ef | grep "nginx: master process" | grep -v grep)" == ""]
then
killall keepalived
fi
fi
EOF

#自启动
systemctl enable keepalived
systemctl start keepalived

高可用服务器1：

hostname highAvailableServer1
yum -y update
yum -y install epel-release

#nginx配置 反向代理+负载均衡配置
yum -y install nginx
vim /etc/nginx/nginx.conf
##http下面添加cache保存目录
http{
	proxy_cache_path /tmp/nginx/cache levels=1:2 keys_zone=STATIC:10m inactive=24h max_size=50m;
}
##添加upstream服务器组
upstream webCluster{
	server 172.16.1.30;
	server 172.16.1.31;
	server 127.0.0.1:8080 backup;
}
##反向代理web服务器集群
server {
	listen 80;
	location / {
		proxy_pass http://webCluster/;
		proxy_connect_timeout 1;
		proxy_read_timeout 1;
		proxy_send_timeout 1;
		proxy_cache STATIC;
		proxy_cache_valid 200 1d;
	}
}
##定义错误显示服务器
server {
	listen 8080;
	root /web/error/;
	index index.html;
}
systemctl enable nginx
systemctl start nginx
#keepalived配置
yum -y install keepalived配置
##配置keepalived.conf
cat > /etc/keepalived/keepalived.conf << EOF
! Configuration File for keepalived

global_defs {
	router_id NodeB
}
vrrp_script check_nginx{
	script "/root/check_nginx.sh"
	interval 2
	weight 2
}
vrrp_instance VI_1 {
	state backup
	interface eno33554960
	virtual_router_id 51
	priority 100
	advert_int 1
	authentication {
		auth_tyoe proxy_pass
		auth_pass 1234
	}
	virtual_uoaddress {
		8.8.8.8/24 dev ens37
	}
	track_script {
		check_nginx
	}
}
EOF
#监控nginx脚本吗
cat > /root/check_nginx.sh << EOF
#!/bin/bash
if ["$(ps -ef | grep "nginx: master process" | grep -v grep)" == ""]
then
/usr/sbin/nginx
sleep 5
if ["$(ps -ef | grep "nginx: master process" | grep -v grep)" == ""]
then
killall keepalived
fi
fi
EOF

#自启动
systemctl enable keepalived
systemctl start keepalived