Amazon Lightsail each instance's traffic limit in a load balancer

Question

Hello, I have this **urgent situation** and kind of lost even on where should I post this.  
  
There's this project done in WordPress (using Crocoblock) that is already done in a Hostinger shared server (it's horrible, honestly, as every shared server is) and, if my customer explained me correctly, could have up to 20,000 simultaneous accesses at its peak (highly doubt it). The website's main objective is capturing leads (should be about 15,000) in a period of 6-8 days, and is not a very complex website - around 5 pages with a subscription form as one of them.  
  
Problem is, **he set a deadline of 3 days to find the best option, migrate the website and test**, and all of that having **ZERO experience** with AWS - actually, my only experience with web hosting are these terrible shared servers. So, no time and no experience at all, but I'm willing to do it whatever it takes - this project could be a life changer.  
  
I'm still in doubt about these 3 AWS options:  
1. **WP on Lightsail** because it seems simpler to configure and my website is in WP. But I'm unsure it could handle so many simultaneous accesses (looks like  this should be used:  , but not sure if it's enough).  
2. **Elastic Beanstalk** because it seems more scalable and simpler than EC2 (but unsure if configuration is easy).  
3. **EC2** but it seems very difficult to configure compared to the others and there's also the fact that I may not have enough time to configure and learn about it.  
  
What would you recommend in this case?  
  
Other developers that I've talked recommended me EC2 or maybe taking a look at Lightsail, which seems easier to configure, and considering that I have virtually no time at all to do this, is my preferred choice.  
  
And directly related to thread's title, If I choose Lightsail and set up a Load Balancer with multiple instances (following this tutorial: ), how can I measure:  
1. how much traffic a single user can generate just by navigating through 2 or 3 pages;  
2. how many users from item (1) could one single instance of Lightsail handle;  
3. knowing how many users from item (2) each instance could handle, how many instances of Load Balancer do I need;  
  
I highly doubt it will have this many simultaneous accesses. I believe he said this high number just to guarantee that server will be available doesn't matter how many accesses it has. Therefore, if there was any way that I could "auto scale", i.e., set up the server to handle like 2,000 concurrent accesses and enable something that would generate new instances in case this overloads, that seems a perfect fit.  
  
And after all these informations, if this would still be the correct choice or way to proceed... thank you very much for your attention.  
  
Edited by: victorpietro on Oct 14, 2021 10:57 AM  
  
Edited by: victorpietro on Oct 14, 2021 11:47 AM

Answer

Measuring exactly how much traffic an instance would be able to handle is unfortunately not a simple task, and we can't give great estimations of how much traffic an instance can handle because each application is different. One idea is to run a load test (ie, simulating customer traffic rapidly) on a single instance to see how it affects performance. You can always start with smaller instances and scale them up (by snapshotting the instance and creating a larger instance from the snapshot: https://lightsail.aws.amazon.com/ls/docs/en_us/articles/how-to-create-larger-instance-from-snapshot-using-console).  
  
In terms of how many load balancers would be needed, I don't see why you would need more than one load balancer, unless you need to spread across multiple regions.  
  
In the Metrics tab on the instance details page, you'll be able to see CPU utilization metrics. The graph has a "sustainable zone", and if the CPU frequently exceeds this limit, you may see performance degradations. You can set alarms on your instances so that you are notified if your instances are exceeding this sustainable zone. Then you can manually add more instances to the load balancer or scale up existing ones.  
  
Lightsail unfortunately does not offer an instance auto-scaling feature. EC2 does offer auto-scaling (https://aws.amazon.com/ec2/autoscaling/), but I agree that it's a bit more difficult to configure than Lightsail.  
  
I hope this helps. Thank you for considering Amazon Lightsail.  
  
-Maxwell

Amazon Lightsail each instance's traffic limit in a load balancer

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