When running Delinkcious on GKE with the Istio add-on, you get automatic integration with Stackdriver, which is a one-stop shop for monitoring, including metrics, centralized logging, error reporting, and distributed tracing. Here is the Stackdriver log viewer for when you are searching for the link-manager logs:
Alternatively, you can filter by service name through the drop-down list. Here is what it looks like when specifying the api-gateway:
Sometimes, the error reporting view is what you need:
Then, ...