4 · Data engineering

10. Orchestration and Pipeline Reliability

DAGs, scheduling, dependencies, retries, SLAs and observability.

9 min read · 3 MCQs

DAGs and schedulers

Orchestrators (Airflow, Dagster, Prefect) model work as a directed acyclic graph of tasks with dependencies, schedules and retries. Tasks should be small, idempotent and parameterised by the logical execution date rather than 'now'.

Failure handling

Configure retries with backoff for transient failures, timeouts so a hung task cannot block the schedule, and alerts on SLA misses. Sensors that wait for upstream data should time out rather than occupy a worker indefinitely.

Observability of data

Track per-run row counts, freshness, schema changes and runtime. A pipeline that succeeds while producing zero rows is a failure that green dashboards will happily hide.

Chapter quiz

3 questions · pass mark 75%
  1. 1. Tasks should depend on the logical execution date because…

  2. 2. A run that completes with zero rows should be…

  3. 3. DAG means…

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