Questions
1 of 5
Basics
Cluster Architecture
Topics, Partitions and Records
Producers
Consumers
Consumer Groups
Offset Management
Replication and Fault Tolerance
Storage Internals
Networking and Request Processing
Performance and Throughput
Delivery Semantics
Transactions
Kafka Streams
Kafka Connect
Schema and Serialization
Security
Error Handling and Retry Patterns
Ordering and Partitioning Design
Testing
Monitoring and Observability
Debugging and Troubleshooting
Deployment and Operations
Admin and CLI Operations
Reliability and Disaster Recovery
Integration Patterns
Modern Kafka Architecture
Advanced Internals
Scalability and Capacity Planning
Architecture and System Design
Production Best Practices
Expert Edge Cases
Versioning and Upgrades
Admin and CLI Operations
Senior End-to-End Scenarios
Difficulty: 3/10
Operational commands, Topic inspection, Consumer group monitoring
Inspecting topics, partitions, and consumer groups
In production, I use Kafka CLI tools to inspect topic metadata, partition leadership, replication health, and consumer progress before making changes. I start with the bootstrap server, describe the topic, and then inspect the relevant consumer group. I correlate this snapshot with broker and client metrics rather than treating one command as a complete diagnosis.
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- 1
The topic description shows partition IDs, leaders, replicas, and ISR (in-sync replicas). A partition without a usable leader can affect reads and writes.
- 2
Consumer-group output commonly includes CURRENT-OFFSET, LOG-END-OFFSET, and LAG. Lag is an offset difference, not elapsed time.
- 3
Lag isolated to a few partitions can indicate hot keys or uneven processing; lag rising broadly can indicate insufficient capacity, rebalances, or downstream bottlenecks.
- 4
Under-replicated partitions warrant checking broker health and replication metrics before intervening.
- 5
Common mistake: assuming nonzero lag means failure, or that low lag proves business processing is correct. Committed offsets reflect recorded progress, and correctness depends on when the application commits.
- 6
Modern CLI workflows use --bootstrap-server. ZooKeeper-based workflows are obsolete in modern Kafka releases; exact options vary by distribution and version.
Scenario Questions
0-2 years experience
2-5 years experience
5-8 years experience
- 1A developer says messages are not appearing in a new topic. Which commands verify the topic exists and partitions have leaders? Explain how you would verify the result.
- 2A consumer-group description shows lag on one partition. How would you check whether its committed offset is advancing? What metrics would you monitor?
8+ years experience
- 1After a deployment, lag rises on two partitions but not others. How would you narrow down the cause? How would you automate and govern this process?
- 2A broker restart is followed by under-replicated partitions. How would you determine whether replication is recovering normally? How would you recover safely from a partial failure?