Nginx：负载均衡

Nginx：负载均衡

1.轮询

1.1.普通轮询

    # 上游服务器
    upstream servers {
        server 192.168.1.201:3001;
        server 192.168.1.201:3002;
        server 192.168.1.201:3003;
    }

server {
    listen       80;
    server_name  localhost;

    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        # 反向代理
        proxy_pass http://servers; 
        proxy_set_header X-Real-IP $remote_addr;
    }
    ...
}

1.2.权重轮询

    # 上游服务器
    upstream servers {
        server 192.168.1.201:3001 weight=2;
        server 192.168.1.201:3002;
        server 192.168.1.201:3003;
    }

server {
    listen       80;
    server_name  localhost;

    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        # 反向代理
        proxy_pass http://servers; 
        proxy_set_header X-Real-IP $remote_addr;
    }
    ...
}

2.hash

2.1.ip_hash

    # 上游服务器
    upstream servers {
        ip_hash;
        server 192.168.1.201:3001;
        server 192.168.1.201:3002;
        server 192.168.1.201:3003;
    }

server {
    listen       80;
    server_name  localhost;

    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        # 反向代理
        proxy_pass http://servers;
        proxy_set_header X-Real-IP $remote_addr;
    }
    ...
}

2.2.url_hash

    # 上游服务器
    upstream servers {
        hash $request_uri;
        server 192.168.1.201:3001;
        server 192.168.1.201:3002;
        server 192.168.1.201:3003;
    }

server {
    listen       80;
    server_name  localhost;

    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        # 反向代理
        proxy_pass http://servers;
        proxy_set_header X-Real-IP $remote_addr;
    }

    #error_page  404              /404.html;

    # redirect server error pages to the static page /50x.html
    #
    error_page   500 502 503 504  /50x.html;
    location = /50x.html {
        root   /usr/share/nginx/html;
    }
    ...
}

3.least_conn

最少连接

    # 上游服务器
    upstream servers {
        least_conn;
        server 192.168.1.201:3001;
        server 192.168.1.201:3002;
        server 192.168.1.201:3003;
    }

server {
    listen       80;
    server_name  localhost;

    #access_log  /var/log/nginx/host.access.log  main;

    location / {
        # 反向代理
        proxy_pass http://servers;
        proxy_set_header X-Real-IP $remote_addr;
    }
    ...
}

4.负载均衡参数

• weight: 权重
• down: 禁用服务器
• backup: 备用服务器，在其他服务器都不可用时会启用
• max_fails: 最大失败的次数
• fail_timeout: max_fails之后，禁用时间
• max_conns: 限制最大连接数

5.参考

• Module ngx_http_upstream_module
• Module ngx_http_headers_module