12.12 Self-test

Why must you restrict access to the CLI tools even if you've configured ACLs?

Why should tool version match broker version, and what's the safest practice?

Give two topic-naming rules and the concrete failure each prevents.

Which of --if-exists / --if-not-exists is recommended, and why is the other dangerous?

Order these by severity and say what each means for producers and consumers: under-replicated, at-min-ISR, under-min-ISR, unavailable.

Why are URPs "not necessarily bad"? What should you actually alert on?

Interpret Replicas: 0,1 Isr: 0 with min-ISR 1. What happens if broker 0 now fails?

Two reasons to add partitions. What breaks when you do, and what's the standing advice?

Why can't you reduce partitions? Give both workarounds.

Why is deleting an unused topic worth doing at all?

What must be true for --delete to work, and how do you confirm it succeeded?

Why should you delete only one or two topics at a time?

Define CURRENT-OFFSET, LOG-END-OFFSET, and LAG precisely.

What must be true to delete a consumer group? What's the alternative if you only want to clear one topic's offsets?

Give the safe six-step offset-reset workflow. What single flag separates export from destruction?

Why won't imported offsets take effect if consumers are running?

Explain the per-broker quota trap with the 5-broker / 10 MBps example.

Why should each consumer group have a unique client.id?

What does --describe on a topic config not show, and which API does show it?

Which topic config fixes Ch. 2's synchronized-segment-roll storm? Which two govern GDPR compaction timing?

What does message.downconversion.enable let you do, and what Ch. 6 problem does that address?

Name three notable broker-level dynamic configs. Why does one of them matter for incident response?

Why does leadership get skewed after a rolling restart, and what are the three remedies?

Distinguish --property, --producer-property, and --consumer-property.

How does the console producer decide the key? What happens with no separator?

Name the four message formatters and one use for each.

Write the command to inspect __consumer_offsets. Name the three non-obvious things it needs.

Walk the three steps of a partition reassignment. Which two files must you save, and why?

What does the controller actually do during a reassignment? What temporarily changes?

What are --additional, --disable-rack-aware, and --throttle for? Which combination is the emergency brake?

Why does moving leadership off a broker before reassignment speed things up? What must you disable temporarily?

How do you change a topic's replication factor? Why doesn't changing the cluster default suffice?

Give both caveats of --cancel.

What does kafka-dump-log.sh --print-data-log show you, and how do its fields map to the v2 batch header from Ch. 6?

Why does replica verification exist — what gap in replication does it detect? What does it cost to run?

When would you delete the /admin/controller znode, and what can't you control about the outcome?

Give both scenarios where topic deletion gets stuck, and the two-part fix.

List the four steps of manual topic deletion. What's the prerequisite, and which child-node gotcha will bite you?

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