Luca Lusso Wellnet, Milan, Italy Our Drupal 8 websites are true applications, often very complex ones. More and more workload is being delegated to external systems, usually microservices, that are used for many different tasks. Software architectures are becoming more distributed and fragmented. To track down problems and optimize for performance, it will become mandatory to trace the lifecycle of a single request as it originates from a client, passes through all Drupal subsystems, reaches external (micro)services and comes back. This is often time consuming and without the right tools may become very difficult. A simple, unstructured log stream isn't enough anymore; we need to find a way to observe the details of what is going on. Observability is what it’s all about. This is based on structured logs, metrics and traces. In this talk you will see how to implement these techniques in Drupal, which tools and which modules to use to trace and log all requests that reach our website and how to expose and display useful metrics. We will integrate Drupal with OpenTracing, Prometheus, Monolog, Grafana and many more.