HDDS-15099. [Docs] Implementation of Write Operations

[cychiu8]

What changes were proposed in this pull request?

Provide the document for every part of a write request from beginning to end.

What is the link to the Apache Jira?

https://issues.apache.org/jira/browse/HDDS-15099

How was this patch tested?

Reviewed the rendered page in the local preview.

CI passed: https://github.com/cychiu8/ozone-site/actions/runs/39021800409

[cychiu8]

@jojochuang , @chungen0126 Here’s the doc for "Implementation of Write Operations". I’d appreciate your review whenever you have time. Thank you!

[jojochuang]

LGTM — clear reservation → data transfer → commit story, HA preExecute vs validateAndUpdateCache split, quota check/charge, Ratis vs EC, and open-key cleanup. Nice upgrade from the old draft.

Optional follow-ups (non-blocking):

1. ACL types per RPC — Document explicitly: CreateKey → CREATE (resolveBucketAndCheckKeyAcls); AllocateBlock and CommitKey → WRITE on the open key + client id (resolveBucketAndCheckOpenKeyAcls).
2. Authorizer — One line that policy checks go through the configured OM authorizer (Native ACLs or Ranger), not only the internal OzoneAclUtils volume/bucket rules.
3. Leader preExecute ordering — Note that SCM block allocation (and tokens) on the leader can run before ACL in preExecute; deterministic validation is in validateAndUpdateCache on all OMs.
4. Zero-length keys — If dataSize is unset or ≤ 0, create skips SCM block allocation.
5. Open-key cleanup — Besides ozone.om.open.key.expire.threshold (default 7d), mention lease/hsync handling (leaseThreshold in OpenKeyCleanupService), not creation time alone.
6. Quota nuance — FSO may increment namespace for missing parent directories at create; byte charge for the key still aligns with commit (already mostly covered).
7. Summary table — Phase 1 could footnote FSO (openFileTable / fileTable) vs OBS/LEGACY table names.
8. Cross-link — Link EC section to Erasure Coding.
9. Scope — Short paragraph: multipart upload, S3 Gateway (same OM RPCs), Ratis streaming, and pipeline failover/exclude lists are out of scope or defer to other pages.
10. HSync — When 04-hsync.md is completed, link from the “invisible until commit” discussion.
11. Nit — Formatting: space before (default 7d) on the open-key threshold property.

Happy to help on a small follow-up doc PR if useful.

[jojochuang]

Merged. Thanks @cychiu8