You need alerts when average container memory usage on GKE is below 20% or above 80%. How should you configure alerts?

The most effective and native way to monitor and alert on GKE container memory usage is by using Cloud Monitoring. Cloud Monitoring provides built-in metrics for GKE, including container memory usage, and allows you to create alerting policies based on these metrics. This approach is fully managed, scalable, and integrates seamlessly with GKE. Creating a Cloud Function to poll the Monitoring API is an overly complex and less efficient solution than using Cloud Monitoring's native alerting capabilities. Similarly, running kubectl top from a scheduled Cloud Function or writing a script to read OS-level metrics are inefficient and non-standard approaches for monitoring GKE container resources. These methods would require significant custom development and maintenance, and they wouldn't leverage the robust monitoring infrastructure already provided by Google Cloud.