Nginx负载均衡的任务调度与健康检查

http {
    upstream backend {
        server backend1.example.com;
        server backend2.example.com;
        server backend3.example.com;
    }

    server {
        listen 80;

        location / {
            proxy_pass http://backend;
        }
    }
}

http {
    upstream backend {
        server backend1.example.com;
        server backend2.example.com;
        server backend3.example.com;

        check interval=3000 rise=2 fall=3 timeout=1000;
    }

    server {
        listen 80;

        location / {
            proxy_pass http://backend;
        }
    }
}

http {
    upstream backend {
        server 10.0.0.1 weight=3;
        server 10.0.0.2 weight=2;
        server 10.0.0.3 weight=1;

        check interval=3000 rise=2 fall=3 timeout=1000 fail_timeout=10s;
        check_http_send "GET /health HTTP/1.0

";
        check_http_expect_alive http_2xx http_3xx;
    }

    server {
        listen 80;

        location / {
            access_by_lua_block {
                -- 加权轮询调度算法
                local peer = ngx.shared.backend:get("current_peer")
                if not peer then
                    peer = "1"
                    ngx.shared.backend:set("current_peer", peer)
                end
                ngx.var.proxy_pass = "http://backend" .. peer
                ngx.shared.backend:incr("current_peer", 1, 1)

                -- 自定义健康检查
                local status = ngx.ctx.balancer_address.status
                if status ~= ngx_balancer.BALANCER_STATUS_OK then
                    ngx.exit(ngx.HTTP_SERVICE_UNAVAILABLE)
                end
            }
            proxy_pass http://backend;
        }
    }
}