Monthly Archives: August 2012

3 Things You Must Know If You Develop on Amazon Web Services (EC2)

Amazon Web Services (AWS) is a great way to begin building highly-scalable, durable web apps almost immediately… er, which is a bit of a problem. If you’re developing applications on AWS, here are three important tips to keep in mind before diving in head first.

Never run anything important on a single EC2 instance.

If take one thing away from this blog post, please remember:

Amazon Web Services is fundamentally different than traditional hosting.

EC2 instances are not durable—they can (and sometimes do) suddenly vanish, taking whatever data you had stored on it. Your application has to be built with this possibility in mind and your AWS architecture should be designed with redundant components to compensate. This would include such things as:

  • storing user-uploaded files in Amazon S3 rather than on the instance
  • using an Elastic Load Balancer in front of a minimum of two application servers, each in a different availability zone
  • using one of Amazon’s cloud-based persistent datastores (SimpleDB, RDS, DynamoDB, etc) rather than installing your own database on EC2. (Or, at least setting up a proper replication strategy if you do have a need to roll your own solution.)
  • maintaining copies of important data entirely outside of Amazon’s cloud platform

Properly developing on AWS requires a change in mindset and a solid understanding of the underlying platform (either through training or experience). Treating AWS as a traditional dedicated server or VPS will result in a deployment that is more complex, less durable, and yet more costly than the alternatives. If your data is important, take the time to read up on AWS best practices or retain the services of an experienced AWS consultant.

Elastic Beanstalk can save you a lot of time.

Elastic Beanstalk is a PaaS-like configuration/deployment framework for Amazon Web Services. Similar to Google App Engine or Heroku, as a developer you can simply upload your source bundle to AWS and application deployment automagically happens—there’s no configuring Apache or even a need to SSH into the instances. Elastic Beanstalk acts as an abstraction layer on-top of EC2 to make it super simple to build autoscaling, durable web apps. Additionally, there are no extra costs for Elastic Beanstalk; you’re simply billed for the Amazon Web Services resources it provisions on your behalf.

I recommend Elastic Beanstalk very frequently to my clients when I consult on their AWS projects. For the most part, it allows their developers to stay focused on the code rather than having to fiddle with server settings. It can save a lot of time and, for plain vanilla LAMP, Java, or Flask/Django apps, it works great. However, sometimes the flip side of “user friendly” is “expert hostile.” If you need to color outside of the lines by using a custom Apache configuration (or ditch it all together for Nginx), you’ll find that you start fighting with the platform. Likewise, if you’re a Ruby on Rails or a Pyramid developer, you’ll also have to look elsewhere. For advanced deployments, Cloud Formation can often be used where Elastic Beanstalk isn’t a good fit.

Easily reduce your Amazon Web Services costs by 40-50%

Buying reserved EC2 instances allow an Amazon Web Services customer to pay a one-time, up-front fee in exchange for a 40-50% discount on the hourly cost for an EC2, RDS, ElastiCache, or DyanmoDB instance. Both one-year and three-year terms are available.

For most production deployments running a web app that’s available 24/7, buying reserved instances is a no-brainer for all but the most seriously cash-strapped start-ups. As an example, let’s calculate the yearly instances costs for a simple, fault-tolerant LAMP stack deployment under Elastic Beanstalk.

Standard, On-demand Instances

Role Instance Type Hourly Cost Up-front Cost Yearly Cost (24/7 utilization)
Elastic Load Balancer $0.025 $219.00
App Server A Small Linux EC2 Instance $0.08 $700.80
App Server B Small Linux EC2 Instance $0.08 $700.80
Database Small Multi-AZ RDS Instance $0.21 $1,839.60
Annual Cost $3,460.20

Heavy Utilization Reserved Instances (1-Year Term)

Role Instance Type Hourly Cost Up-front Cost Yearly Cost (24/7 utilization)
Elastic Load Balancer $0.025 $219.00
App Server A Small Linux EC2 Instance $0.016 $195.00 $140.16
App Server B Small Linux EC2 Instance $0.016 $195.00 $140.16
Database Small Multi-AZ RDS Instance $0.106 $138.00 $928.56
Annual Cost $1,955.88

The cost savings equate to $1,504.32 (or nearly 44% off your Amazon Web Services bill!) over the course of 12 months using reserved instances. Reserved EC2 instances are available in light, medium, and heavy utilization types to fit different usage scenarios. “Heavy utilization” types will get you the most bang for the buck for “always on” instances, but light and medium can also significantly reduce costs (while requiring a smaller up-front payment). It’s worth noting that bandwidth and EBS disk I/O is billed separately and are not affected by reserved instance pricing.

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