[marcos-casagrande]

For those who perform thousand or millions of requests per day, and need a solution to this issue:

It’s quite normal to get getaddrinfo EAI_AGAIN errors when performing a lot of requests on your server. Node.js itself doesn’t perform any DNS caching, it delegates everything DNS related to the OS.

You need to have in mind that every http/https request performs a DNS lookup, this can become quite expensive, to avoid this bottleneck and getaddrinfo errors, you can implement a DNS cache.

http.request (and https) accepts a lookup property which defaults to dns.lookup()

http.get('http://example.com', { lookup: yourLookupImplementation }, response => {
    // do something here with response
});

I strongly recommend to use an already tested module, instead of writing a DNS cache yourself, since you’ll have to handle TTL correctly, among other things to avoid hard to track bugs.

I personally use cacheable-lookup which is the one that got uses (see dnsCache option).

You can use it on specific requests

const http = require('http');
const CacheableLookup = require('cacheable-lookup');

const cacheable = new CacheableLookup();

http.get('http://example.com', {lookup: cacheable.lookup}, response => {
    // Handle the response here
});

or globally

const http = require('http');
const https = require('https');
const CacheableLookup = require('cacheable-lookup');

const cacheable = new CacheableLookup();

cacheable.install(http.globalAgent);
cacheable.install(https.globalAgent);

NOTE: have in mind that if a request is not performed through Node.js http/https module, using .install on the global agent won’t have any effect on said request, for example requests made using undici

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