Varnish Controller

API Logs

These are logs used for the API interface toward Varnish Controller. These should not be confused with Varnish logs, which are different. The API logs are just events in the Varnish Controller itself, such as API call errors. As an example, a compilation of a VCL that fails will generate a new log entry with the error that the Varnish compiler printed.

Object Tracing

The API logs contain a keyType and a keyId that can be used to filter out API logs for a particular resource. The keyType tells what resource type was affected and the ID specifies the exact ID affected. If the ID is 0, no existing resources were affected.

Trace ID

The logs also contain a traceId that can be used to track events throughout the Varnish Controller system. The trace ID is used by API-GW, Brainz and Agents to log events related to the particular API request. Looking into the system logs this ID can be filtered out to see what went wrong while debugging. The trace ID can be tracked from API-GW to Brainz and all the way to a particular agent.


The log entries have a severity assigned, these are:

  • (1) Info - Informational message, not critical.
  • (2) Warning - Warning message, could be caused by user error.
  • (3) Error - Critical error