Often, an application that has significant growth in its user base isn’t ready for this. Requirements for speed and availability are growing, and infrastructure and application architecture don`t allow them to be met.
My task was to improve the application infrastructure and quality. The app managed to grow from an MVP and a stand for a single client into a popular SaaS. The lack of fault tolerance and service components’ scalability began to significantly interfere with users. It was time to adapt the application to a cluster mode.
The application was deployed in containers, and the orchestration was performed by Docker Compose. The application components were not designed to be run in cluster mode. I guess it is often the case for many apps in their early stages. The business is more focused on getting new features, and it isn`t always possible and necessary to waste any time on such premature optimization. At some point though, stability and speed become the top priorities.