For analysis purposes, you need to send all the logs from all of your Compute Engine instances to a BigQuery dataset called platform-logs. You have…

The most direct, cost-effective, and officially recommended method to send logs from Cloud Logging to BigQuery is by creating a log sink. A sink allows you to define a filter for specific logs (in this case, from Compute Engine instances using resource.type="gceinstance") and route them directly to a supported destination. Choosing BigQuery as the sink destination is a native integration that is optimized for this purpose. This approach avoids the additional cost and complexity of intermediate services like Pub/Sub and Cloud Functions, thereby minimizing both operational overhead and cost, as required by the question.

A. The instance metadata key logs-destination is not a valid or standard configuration parameter for the Cloud Logging agent to specify a BigQuery destination.

B. This solution introduces unnecessary intermediate services (Pub/Sub and Cloud Functions), which add complexity and incur their own costs for message delivery and function execution, violating the "minimize cost" requirement.

D. This describes a complex, daily batch process. It introduces latency (up to 24 hours), is more expensive due to using Cloud Scheduler and Cloud Functions, and is less reliable than a real-time sink.

1. Google Cloud Documentation - Overview of log routing and sinks: "To route logs

you create a sink. A sink includes a destination and a filter that selects the log entries to route... You can route log entries to the following destinations: ... BigQuery dataset". This document establishes the sink as the primary mechanism for routing logs.

Source: Google Cloud Documentation

"Overview of log routing and sinks"

Section: "How sinks work".

2. Google Cloud Documentation - Exporting logs to BigQuery: "To export logs to BigQuery

you create a sink and set BigQuery as the destination... The sink creates a new BigQuery dataset and then creates tables with a schema for the logs." This page details the exact procedure described in option C.

Source: Google Cloud Documentation

"Route logs to supported destinations"

Section: "Route logs to BigQuery".

3. Google Cloud Documentation - Cloud Logging Pricing: "There is no charge for routing logs to a supported destination; however

the destination might have its own ingestion costs." This supports the cost-minimization argument by showing that the routing itself is free

so avoiding extra billable services (like Pub/Sub and Functions) is the most economical approach.

Source: Google Cloud Documentation

"Cloud Logging pricing"

Section: "Log routing".

4. Google Cloud Documentation - Logging agent configuration: The official documentation for configuring the google-fluentd agent does not list a logs-destination metadata key for routing logs

confirming that the method in option A is incorrect. Configuration is managed through agent configuration files

not instance metadata for this purpose.

Source: Google Cloud Documentation

"Logging agent - Advanced configuration".