nginx 负载均衡有 （轮询策略<round-robin>，加权轮询）、最少链接数<Least-connected >、ip-hash
轮询策略
http {
upstream myapp1 {
server srv1.example.com;
server srv2.example.com;
server srv3.example.com;
}
server {
listen 80;
location / {
proxy_pass http://myapp1;
}
}
}
加权轮
upstream myapp1 {
server srv1.example.com weight=3;
server srv2.example.com;
server srv3.example.com;
}
最少链接数
upstream myapp1 {
least_conn;
server srv1.example.com;
server srv2.example.com;
server srv3.example.com;
}
ip-hash
upstream myapp1 {
ip_hash;
server srv1.example.com;
server srv2.example.com;
server srv3.example.com;
}
但当有一个服务因为失败次数达到设置的阀值，会被nginx标记为错误的服务器，因而避免对他的访问
https://nginx.org/en/docs/http/load_balancing.html
