Discussion More Information • Self Awareness Example • Expose Pod Information to Containers Through Files • Expose Pod Information to Containers Through Environment Variables • Amazon ECS Container Agent Introspection • Instance Metadata and User Data On many occasions, an application needs to be self-aware and have information about itself and the environment in which it is running. Kubernetes provides nonin‐ trusive mechanisms for introspection and metadata injection. One of the downsides of the Downward API is that it offers a fixed number of keys that can be referenced. If your application needs more data, especially about other resources or cluster-related metadata, it has be queried on the API Server. This technique is used by many applications that query the API Server to discover other Pods in the same namespace that have certain labels or annotations. Then the application may form a cluster with the discovered Pods and sync state, for example. It is also used by monitoring applications to discover Pods of interest and then start instrumenting them. Many client libraries are available for different languages to interact with the Kuber‐ netes API Server to obtain more self-referring information that goes beyond what the Downward API provides. Discussion | 121