add PostgreSQL node migration and CloudBeaver solutions (MIDDLEWARE-31526)

[SuJinpei]

Summary

Precipitates historical internal Confluence KB PostgreSQL solutions into the GitHub KB (alauda/knowledge), part of MIDDLEWARE-31526 (KB 沉淀 / 对标 OCP). Modernized to the current acid.zalan.do/v1 postgresql CR, verified live on ACP 4.2 and 4.3, bilingual (en + zh).

Solutions (2, bilingual)

• KB260515007 — How to Migrate a PostgreSQL Instance to Another Node
• KB260515008 — How to Deploy CloudBeaver for PostgreSQL Management

Verification

• Node migration: on ACP 4.2/4.3, deleting a replica's PVC + pod recreated the member, re-synced from the leader via streaming replication, and a previously-written marker row was present on the resynced member.
• CloudBeaver: deploys as a single-pod Deployment and reaches the PostgreSQL Service on 5432; doc adds an air-gapped/IPv6 image-mirror note (the public dbeaver image is otherwise unreachable from such clusters).

The CloudBeaver guide parallels the existing How_to_Deploy_CloudBeaver_for_MySQL_Management (KB260515005).

🤖 Generated with Claude Code

Summary by CodeRabbit

• Documentation
  • Added guide for deploying CloudBeaver web SQL client for PostgreSQL management on Kubernetes, including installation steps, initial setup, and connection configuration.
  • Added guide for migrating PostgreSQL cluster instances between nodes on local storage, covering scheduling constraints and pod recreation procedures.

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ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 096224ca-e590-4ba8-9622-c38d6f226a54

📥 Commits

Reviewing files that changed from the base of the PR and between 73e1b5d and d80a95e.

📒 Files selected for processing (2)

• docs/en/solutions/How_to_Deploy_CloudBeaver_for_PostgreSQL_Management.md
• docs/en/solutions/How_to_Migrate_a_PostgreSQL_Instance_to_Another_Node.md

Walkthrough

Adds two new solution documentation pages: one guides users through deploying CloudBeaver (web SQL client) on Kubernetes for PostgreSQL management, including a full manifest, deployment steps, UI setup, and PostgreSQL connection; the other documents migrating a PostgreSQL Operator–managed instance to a different node when using node-local storage via PVC/pod deletion and Patroni re-cloning.

Changes

CloudBeaver Deployment Guide

Layer / File(s)	Summary
Manifest definition and deployment commands docs/en/solutions/How_to_Deploy_CloudBeaver_for_PostgreSQL_Management.md	Front matter, issue/environment context, full cloudbeaver.yaml manifest (PVC, Deployment, NodePort Service), air-gapped/IPv6 image notes, deployment commands, and NodePort URL discovery method.
Initial setup, PostgreSQL connection, and uninstall docs/en/solutions/How_to_Deploy_CloudBeaver_for_PostgreSQL_Management.md	Admin password setup, login, PostgreSQL cluster connection steps (service endpoint and superuser password retrieval from Secret), uninstall procedure, and PVC preservation instructions for redeploys.

PostgreSQL Instance Node Migration Guide

Layer / File(s)	Summary
Overview, environment, and scheduling control docs/en/solutions/How_to_Migrate_a_PostgreSQL_Instance_to_Another_Node.md	Front matter, explanation of why node-local volumes cannot reschedule, how PVC/pod deletion triggers Patroni re-cloning, and prerequisite steps to label nodes and patch nodeSelector on the PostgreSQL CR.
Sequential migration procedure and operational notes docs/en/solutions/How_to_Migrate_a_PostgreSQL_Instance_to_Another_Node.md	Steps to confirm placement/leader, migrate non-leader members by deleting PVC and pod, verify replica streaming state, optional leader switchover, scheduling restoration, and notes on one-at-a-time migration and the single-instance scale-to-two workaround.

Estimated code review effort

🎯 1 (Trivial) | ⏱️ ~5 minutes

Poem

🐇 Two new guides have hopped into view,
One for CloudBeaver, fresh and brand new,
One moves a Postgres pod to a different place,
PVCs deleted, Patroni picks up the pace!
Streaming replicas re-sync without fuss —
The rabbit approves, no drama from us. 🌿

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Description Check	✅ Passed	Check skipped - CodeRabbit’s high-level summary is enabled.
Title check	✅ Passed	The title clearly and concisely describes the main changes: adding two new PostgreSQL solutions (node migration guide and CloudBeaver deployment guide) with a reference to the associated ticket.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check.
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

_{✏️ Tip: You can configure your own custom pre-merge checks in the settings.}

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Create PR with unit tests
• Commit unit tests in branch docs/add-postgresql-kb-solutions-31526

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[coderabbitai]

Actionable comments posted: 2

🤖 Prompt for all review comments with AI agents

Verify each finding against current code. Fix only still-valid issues, skip the
rest with a brief reason, keep changes minimal, and validate.

Inline comments:
In `@docs/en/solutions/How_to_Deploy_CloudBeaver_for_PostgreSQL_Management.md`:
- Around line 145-146: The kubectl exec command that attempts to echo the
PGPASSWORD_SUPERUSER environment variable will output nothing because the Alauda
PostgreSQL Operator stores credentials in Kubernetes Secrets, not pod
environment variables. Replace the documented command that uses bash -c 'echo
$PGPASSWORD_SUPERUSER' with a kubectl get secret command that retrieves and
decodes the password directly from the Kubernetes Secret created by the operator
for the cluster. The new command should use kubectl get secret with the
appropriate namespace and secret name, extracting the password key and decoding
the base64-encoded value to display the actual superuser password.

In `@docs/en/solutions/How_to_Migrate_a_PostgreSQL_Instance_to_Another_Node.md`:
- Around line 65-67: The kubectl label command in the example is applying the
`target=true` label to both the source and target nodes, which allows the
recreated pod to schedule to either node when using `nodeSelector: target=true`.
To fix this, modify the labeling command to apply the label only to
`<target-node>`, removing `<source-node>` from the command. This ensures the pod
will only schedule to the intended target node during recreation.

🪄 Autofix (Beta)

Fix all unresolved CodeRabbit comments on this PR:

• Push a commit to this branch (recommended)
• Create a new PR with the fixes

---

ℹ️ Review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: CHILL

Plan: Pro

Run ID: 8f4f0cce-e79f-4cb2-9612-fe83d5a42468

📥 Commits

Reviewing files that changed from the base of the PR and between f8f79ab and 73e1b5d.

📒 Files selected for processing (2)

• docs/en/solutions/How_to_Deploy_CloudBeaver_for_PostgreSQL_Management.md
• docs/en/solutions/How_to_Migrate_a_PostgreSQL_Instance_to_Another_Node.md