Availability and Cost Requirements
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This course covers the core learning objective to meet the requirements of the 'Designing Compute instances solutions in AWS - Level 2' skill

Learning Objectives:

  • Create elastic and scalable AWS compute solutions for a specific workload
  • Evaluate an appropriate AWS compute service based on business requirements
  • Evaluate which Elastic Load Balancer should be used for a specific solution



It's always a delicate balance to find that sweet spot where your application is highly available to your audience and at the same time you're not paying for expensive servers that are underutilized. Let's consider Compute options from the perspective of cost savings and availability. Spot Instances. For Compute intensive application, Spot Instances are the absolute best choice. It simply means buying Amazon's unused EC2 compute capacity at a huge discount. One disadvantage is that if your application requires near 100% availability, then this may not be the optimal solution since Amazon can reclaim the Spot Instances from you on short notice. That said, they can be combined with other Compute options to meet the availability requirements at a higher cost. Serverless. If your application only runs short-lived transactions, serverless may be able to save you a lot in cost. 

However, if your applications run long processes or has a very high transaction load, say hundreds or even thousands of transactions per second, then serverless may not be the best choice. Auto Scaling. Auto Scaling not only helps with cost savings, but also helps with availability because it forces you to use more than one availability zone in your design in order to take full advantage of it. Reserve Instances. This is simply the action of pre-paying for your EC2 compute capacity if you know you'll be using it for several months or even years. This is guaranteed capacity, which in contrast with the Spot Instances, these are guaranteed to be available to you. It's a great cost saving options right in the middle between on-demand pricing and a spot instance pricing. As with everything in life, the actual answer to making your application highly available and also running it at a low cost lies somewhere between these options. For instance, combining auto scaling with spot pricing gives you higher availability while keeping costs down.


About the Author
Learning Paths

Stuart has been working within the IT industry for two decades covering a huge range of topic areas and technologies, from data center and network infrastructure design, to cloud architecture and implementation.

To date, Stuart has created 150+ courses relating to Cloud reaching over 180,000 students, mostly within the AWS category and with a heavy focus on security and compliance.

Stuart is a member of the AWS Community Builders Program for his contributions towards AWS.

He is AWS certified and accredited in addition to being a published author covering topics across the AWS landscape.

In January 2016 Stuart was awarded ‘Expert of the Year Award 2015’ from Experts Exchange for his knowledge share within cloud services to the community.

Stuart enjoys writing about cloud technologies and you will find many of his articles within our blog pages.