🧠Apache Flink Interview Questions You Must Prepare For
Whether you're preparing for interviews or brushing up on Flink, here’s a categorized list of essential questions to focus on:
🔹 Core Flink Concepts
- What is Apache Flink and how does it differ from Spark or Storm?
- What is the difference between DataStream and DataSet API in Flink?
- What are the key components of Flink's architecture?
- Explain how checkpointing and state backends work in Flink.
- What is the role of the JobManager and TaskManager?
🔹 Real-Time Stream Processing
- How do you handle late events in Flink?
- What are watermarks and why are they important?
- Explain windowing in Flink. What types of windows have you worked with (Tumbling, Sliding, Session)?
- What is event time vs processing time in Flink?
- How do you ensure exactly-once or at-least-once processing in your jobs?
🔹 State Management
- What are keyed vs operator states?
- How do you manage large states in Flink jobs?
- Which state backend are you using and why (RocksDB, MemoryStateBackend, FsStateBackend)?
- How does Flink handle state recovery during failure?
🔹 Fault Tolerance & Checkpointing
- How is checkpointing configured and triggered in Flink?
- What’s the difference between savepoints and checkpoints?
- Have you used externalized checkpoints? Why or when?
- How does Flink recover from failures in production?
🔹 Flink with Java – Practical Implementation
- How do you write a custom SourceFunction or SinkFunction?
- Have you used ProcessFunction or KeyedProcessFunction? What for?
- How do you integrate Flink with external systems (e.g., PostgreSQL, Kafka, S3)?
- How do you test your Flink jobs?
🔹 Performance & Optimization
- How do you handle backpressure in Flink?
- How do you optimize Flink jobs for low latency and high throughput?
- Have you tuned task slots, parallelism, or memory configuration?
- How do you monitor and debug performance issues?
🔹 Deployment & Monitoring (Ververica Focus)
- How do you deploy a Flink job using Maven and Ververica?
- What configurations do you set in production for memory, timeouts, or retries?
- How do you monitor Flink jobs in Ververica?
- What kind of alerts or metrics do you track in production?
🔹 Scenario-Based / Behavioral
- Tell me about a time when a Flink job failed in production. How did you debug it?
- Have you ever faced performance degradation in a streaming job? How did you fix it?
- Explain a challenging Flink use case you’ve worked on.
✅ Tip: Be prepared to explain real-world use cases, tools like Ververica/Grafana/Prometheus, and how you troubleshoot issues in production environments.
0 comments:
If you have any doubts,please let me know