A streaming pipeline stopped processing at 2 a.m. The on-call engineer must find the error messages written by the workers and also check the throughput and backlog graphs for the same time window. Which pair of services is most appropriate?
Show answer and explanation
Answer: D
Cloud Logging collects the worker and service log entries that contain the error text, and those entries can be filtered to the failure window. Cloud Monitoring stores metrics such as throughput and backlog and displays them on dashboards for the same period. Using both together supports root-cause analysis. The other pairs are storage, security, networking, messaging or database services rather than observability tools.
Why the other options are wrong
- A. Cloud Storage holds objects and Cloud Armor filters web traffic against attacks. Neither collects worker error logs or pipeline throughput metrics.
- B. Cloud DNS resolves domain names and Cloud NAT gives private instances outbound internet access. Neither reports on pipeline errors or processing performance.
- C. Pub/Sub carries messages between services and Spanner is a database. They are parts of the pipeline itself, but they do not provide logs or metric dashboards for diagnosis.