# 负载均衡算法
轮询（Round Robin）：依次分配
加权轮询（Weighted Round Robin）：按权重分配
最少连接（Least Connections）：分配给连接最少的
IP哈希（IP Hash）：根据IP分配

# 负载均衡工具
HAProxy：专业的负载均衡器
Nginx：Web服务器+负载均衡
LVS：Linux虚拟服务器

# 架构模式
四层负载均衡：基于IP+端口
七层负载均衡：基于应用层协议

# 高可用架构
主备模式：Keepalived + HAProxy
集群模式：多节点负载均衡

# 安装HAProxy
$ sudo dnf install haproxy -y

# 配置HAProxy
$ sudo vi /etc/haproxy/haproxy.cfg
global
log /dev/log local0
maxconn 4096

defaults
log global
mode http
option httplog
timeout connect 5000ms
timeout client 50000ms
timeout server 50000ms

frontend webfrontend
bind *:80
default_backend webservers

backend webservers
balance roundrobin
opti更多学习教程公众号风哥教程itpux_comon httpchk GET /health
server web1 192.168.1.10:80 check
server web2 192.168.1.11:80 check
server web3 192.168.1.12:80 check

# 启动服务
$ sudo systemctl start haproxy
$ sudo systemctl enable haproxy

# 查看状态
$ sudo systemctl status haproxy

# 安装Nginx
$ sudo dnf install nginx -y

# 配置负载均衡
$ sudo vi /etc/nginx/conf.d/loadbalance.conf
upstream webservers {
least_conn;
server 192.168.1.10:80 weight=3;
server 192.学习交流加群风哥QQ113257174168.1.11:80 weight=2;
server 192.168.1.12:80 backup;

keepalive 32;
}

server {
listen 80;

location / {
proxy_pass http://webservers;
proxy_set_header Host $host;
proxy_set_header X-Real-IP $remote_addr;
}
}

# 测试配置
$ sudo nginx -t
nginx: the configuration file /etc/nginx/nginx.conf syntax is ok
nginx: configuration file /etc/nginx/nginx.conf test is successful

# 重启服务
$ sudo systemctl restart nginx

# 场景：部署3节点Web服务负载均衡集群

# 1. 部署后端Web服务器（3台）
# web1: 192.168.1.10
# web2: 192.168.1.11
# web3: 192.168.1.12

# 2. 部署HAProxy负载均衡器
$ sudo vi /etc/haproxy/haproxy.cfg
frontend webfrontend
bind *:80
acl url_static path_beg /static /images /css
use_backend static if url_static
default_backend dynamic

backend static
balance roundrobin
server web1 192.168.1.10:80 check
server web2 192.168.1.11:80 check

backend dynamic
balance leastconn
server web1 192.168.1.10:8080 check
server web2 192.168.1.11:8080 check
server web3 192.168.1.12:8080 check

# 3. 配置健康检查
# 在后端服务器创建健康检查页面
$ echo “OK” >from PG视频:www.itpux.com /var/www/html/health

# 4. 测试负载均衡
$ for i in {1..10}; do curl http://192.168.1.100; done