KAFKA-8913: Document topic based configs & ISR settings for Streams apps

[vinothchandar]

• Documented how to set topic based configs
• Documented how to achieve MIN_IN_SYNC_REPLICAS_CONFIG = 2 for reliable apps

Committer Checklist (excluded from commit message)

• Verify design and implementation
• Verify test coverage and CI build status
• Verify documentation (including upgrade notes)

[vinothchandar]

Copy pasted these onto kafka-site and the site seems to work fine.

See box at the end of picture

See right after "Same applied to ...."

@mjsax Please take a look.. Also can you provide guidance on

• backporting to older kafka releases?
• Also sending a PR to kafka-site repo?

[mjsax]

Merged to trunk and cherry-picked to 2.3, 2.2, 2.1, and 2.0 (seems to be sufficient for me).

If you want the update on the website immediately, please do a PR against kafka-site -- otherwise, it would be effective only when we do a release an update the webpage. You would need to do the update for each release.

[vinothchandar]

@mjsax thanks! To clarify, the next AK release will only update the latest version's doc right? we still need to update older releases?

if not, I am happy to wait for the release.

[mjsax]

Yes. If we release 2.3.1 only 2.3 docs are updated. If we release 2.4.0 only new 2.4 docs are added. Hence, a PR for the webpage should just update all versions for simplicity as we don't know exactly when a bug-fix release might update older docs.