Thousand of concurrent requests - EAI_AGAIN/ECONNRESET error

Question

I need to perform a million API calls in under an hour (The server can handle this much traffic), for this, I'm using node to run multiple requests in parallel, but when I try to run ~1000 concurrent requests I keep getting these errors:

EAI_AGAIN

{ [Error: getaddrinfo EAI_AGAIN google.com:80]
  code: 'EAI_AGAIN',
  errno: 'EAI_AGAIN',
  syscall: 'getaddrinfo',
  hostname: 'google.com',
  host: 'google.com',
  port: 80 }

ECONNRESET

{
    [Error: read ECONNRESET] code: 'ECONNRESET',
    errno: 'ECONNRESET',
    syscall: 'read'
}

How can I prevent this from happening, without reducing the requests to 500?

Here's a code sample that works perfectly when running 500 requests at a time, but fails when the limit is over 1000. (Your limit may be different).

"use strict";
const http = require('http');
http.globalAgent.maxSockets = Infinity;
const async = require('async');
const request = require("request");

let success = 0;
let error = 0;

function iterateAsync() {
    let rows = [];
    for (let i = 0; i < 500; i++) {
        rows.push(i);
    }

    console.time("Requests");
    async.each(
        rows, 
        (item, callback) => get(callback), 
        (err) => {
            console.log("Failed: " + error);
            console.log("Success: " + success);
            console.timeEnd("Requests");
    });
}


function get(callback) {

    request("http://example.com", (err, response, body) => {
        if (err) {
            console.log(err);
            error++;
            return callback();
        }

        success++;
        callback();
    });
}

iterateAsync();

I added http.globalAgent.maxSockets = Infinity; even though is the default value.

500 requests

1000 requests

Aditional info:

I'm running the tests on ubuntu 14.04 & 15.04 and I modified file-max, tcp_fin_timeout, tcp_tw_reuse, ip_local_port_range default values in /etc/sysctl.conf as described in this post

• file-max: 100000
• tcp_fin_timeout: 15
• tcp_tw_reuse: 1
• ip_local_port_range: 10000 65000

Added following lines in /etc/security/limits.conf

*     soft    nofile          100000
*     hard    nofile          100000

With this values, I'm still getting the error.

I've read all other similar posts:

• httpd - Increase number of concurrent requests
• Thousands of concurrent http requests in node
• Increasing the maximum number of tcp/ip connections in linux

Is there a way I can know the exact number of concurrent requests that my system can manage?

Answer 1

Here's how I solved it following @jfriend00 input.

I resolve the host IP address using dns.resolve4 and then perform the requests using the IP, that way the error is gone, and I can perform more requests in less time.

"use strict";

const dns = require("dns");
const http = require('http');

http.globalAgent.maxSockets = Infinity;

const async = require('async');
const request = require("request");

let success = 0;
let error = 0;

function iterateAsync() {
    let rows = [];
    for (let i = 0; i < 500; i++) {
        rows.push(i);
    }

    console.time("Requests");

    dns.resolve4("example.com", (err, addresses) =>{ //Resolve host and obtain IP address

        if(err) //Handle error
            return false;

        async.each(
            rows,
            (item, callback) => get(`http://${addresses[0]}`, callback),
            (err) => {
                console.log("Failed: " + error);
                console.log("Success: " + success);
                console.timeEnd("Requests");
            });

    });


}

function get(host, callback) {

    request(host, (err, response, body) => {
        if (err) {
            console.log(err);
            error++;
            return callback();
        }

        success++;
        callback();
    });
}


//Start requests
iterateAsync();

Output:

Failed: 0
Success: 500
Requests: 6295.799ms