iHeartRadio uses Docker to isolate dependencies and resource usage of applications from each other, leveraging its ability to control dependencies and resource usage. However, monitoring Docker performance was a challenge due to lack of visibility into container-level resource consumption. They use Datadog for infrastructure monitoring, which collects CPU, memory, I/O, and network metrics from each Docker container and can aggregate metrics by any tag or tags. This allows iHeartRadio to monitor service-level metrics by aggregating by Docker image, breaking down network traffic by image and container, and correlating Docker performance with non-Docker services. Datadog also enables rapid changes in internal network traffic to trigger alerts, aiding investigation of issues that arise.