Zero-Downtime Deployment in a High Availability Architecture : Controlled experiment of deployment automation in a high availability architecture

Abstract: Computer applications are no longer local installations on our computers. Many modern web applications and services rely on an internet connection to a centralized server to access the full functionality of the application. High availability architectures can be used to provide redundancy in case of failure to ensure customers always have access to the server. Due to the complexity of such systems and the need for stability, deployments are often avoided and new features and bug fixes cannot be delivered to the end user quickly. In this project, an automation system is proposed to allow for deployments to a high availability architecture while ensuring high availability. The purposed automation system is then tested in a controlled experiment to see if it can deliver what it promises. During low amounts of traffic, the deployment system showed it could make a deployment with a statistically insignificant change in error rate when compared to normal operations. Similar results were found during medium to high levels of traffic for successful deployments, but if the system had to recover from a failed deployment there was an increase in errors. However, the response time during the experiment showed that the system had a significant effect on the response time of the web application resulting in the availability being compromised in certain situations.