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While going through the documentation I came to know about these two tier of environment in AWS, but couldn't find any comparison between them. The suggested thing in documentation is, one should choose Worker Environment for a long running tasks (to increase the responsiveness of Web-tier).

I have a few questions to clarify my doubts:

  1. How two tier are different from each other? (in regards to performing different operations, services available in each etc.)

  2. How do both communicate with each other? (if I developed my front-end app in Web-tier and back-end in Worker-tier)

BinaryButterfly
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John
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1 Answers1

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The most important difference in my opinion is that worker tier instances do not run web server processes (apache, nginx, etc). As such, they do not directly respond to customer requests. Instead, they can be used to offload long-running processes from your web tier.

The tiers communicate with each other via SQS. When your web instance needs to spawn a background job, it posts a message to the shared queue with the job details. A daemon running on the worker instance reads the item from the queue and POSTs a message to an endpoint that your application exposes on http://localhost/.

That being said, I think the web/worker architecture might be overkill in the "front-end/back-end" terms you're describing. Your web tier is fully capable of running both a web server and an application server. If you have requirements for background or asynchronous processing, though, adding a worker tier might make sense.

Brian
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  • Do you know of any docs that confirm that? Although the Worker docs do seem to imply that, when I started a bare Worker, it had Apache running, and listening on port 80. It seems to be so it can handle health-checks, but it's definitely interfering with my running Flask on port-80. – John C Sep 10 '18 at 19:55