what are the kubernetes/elb time outs for http requests?

Just as Pampy mentioned in his answer, the ELB timeout counts only the Idle time. This can range between 1 and 4000 secs and is set to 60 secs by default. You can change the timeout using the CLI or the console.

The following is an example of using the CLI to change it to 5 mins:

aws elb modify-load-balancer-attributes --load-balancer-name my-loadbalancer --load-balancer-attributes "{\"ConnectionSettings\":{\"IdleTimeout\":300}}"

Source: docs

As you are uploading big files taking 20-40 mins, I would still recommend the other suggestions about using a message broker like RabbitM or Kafka to handle the upload and processing asynchronously.

The ELB timeout counts only for "idle" time.That means as long as your upload is still running, it's not idle.When the file arrived at your server, you need to measure the time until your server responds.

When got that correctly, the server will process the request and return a response to the client afterwards.With a default timeout of 60 seconds, your server has these 60 seconds to process the uploaded file and return an answer.

Maybe your server needs less than 60 seconds to process your 25 minutes upload, but more to process the 40 minutes upload?

Why dont you upload the file and push an event to message broker like rabbitMQ. Perform ETL on the files using kubernetes Job/CronJob object asynchronously and accordingly notify the client.

This way, you dont have to block the incoming request for longer time. post upload after the event is published send a message to client that request is being processed.