In previous chapters, we built a state-of-the-art infrastructure and implemented a number of engineering best practices following the DevOps principles. One of the principles we haven't covered yet is the concept of measuring everything.

The core concept of measuring everything is the goal of collecting actionable feedback. We want to create the following feedback loop that will let us assess the impact of a change:

This idea isn't unique to DevOps. Most reputable companies will rely on similar systems to dynamically steer their teams in the right direction, as intuition and gut feeling isn't enough anymore when making most decisions and trying to stay competitive.

By applying this concept to our infrastructure and services, we can take them to the next level and implement a monitoring and alerting solution, which is, of course, a must-have for any production environment. In the first part of the chapter, we will make changes to our application to better expose how our application is behaving. Following this, we will do the same to our infrastructure. Thanks to our understanding of infrastructure as code, we will be able to add those crucial components by extending the different CloudFormation templates we created.

Finally, we will implement an alert functionality on some of the public key metrics indicators to help us improve the availability of our application. This chapter will contain the following sections:

• Instrumenting our application for monitoring
• Monitoring our infrastructure
• Creating alarms using CloudWatch and SNS