docs(upgrades): maintenance page and rolling updates (chart 2.4.0)

[Mtze]

Documents chart 2.4.0 (EduIDE/EduIDE-Helm#47) in the admin upgrade guide:

• the static maintenance page Envoy shows while the landing page has no ready pod
• rolling updates that keep a ready pod
• replicas / PodDisruptionBudgets, and turning PDBs off on single-node clusters
• showing the page on purpose by scaling the landing page to 0

🤖 Generated with Claude Code

Summary by CodeRabbit

• Documentation
  • Documented the maintenance page shown when no landing-page pod is ready, including its 30-second reload and how to disable it when using another router.
  • Added guidance on planned maintenance, upgrade behavior, graceful pod replacement, and resilience to node loss.
  • Clarified that maintenance mode affects the landing page only; REST service errors and active IDE sessions are unaffected.

[coderabbitai]

Navigate logical layers of code changes, visualize relationships, and explore their blast radius.

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: defaults

Review profile: CHILL

Plan: Advanced

Run ID: 2cc6e2c5-5022-4bd5-b179-9af783fc2d8f

📥 Commits

Reviewing files that changed from the base of the PR and between 88a6586 and 2cff1f7.

📒 Files selected for processing (1)

• docs/admins/maintenance/upgrades.md

Included review availability: This review used your included allowance. Your plan provides up to 1 included review per hour; 0 remain after this review.

---

📝 Walkthrough

Walkthrough

The maintenance guide now describes the landing page’s static 503 response, pod replacement and draining during upgrades, and steps for planned maintenance.

Changes

Maintenance guidance

Layer / File(s)	Summary
Landing-page maintenance response docs/admins/maintenance/upgrades.md	Documents the static 503 response when Envoy Gateway has no ready landing-page pod, and the setting to disable the maintenance page when using another router.
Upgrade and planned-maintenance operations docs/admins/maintenance/upgrades.md	Documents pod replacement, draining, replica and disruption-budget behavior, planned scaling commands, and the effects on REST service errors and running sessions.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~4 minutes

Change: Other

Merge Risk: ⚪ Minimal · up to 2cff1

No confirmed issue blocks merging the guidance, but the node-loss and planned-maintenance claims could not be checked against the chart.

Architecture Summary

Architecture risk: 🔵 Low · up to 2cff1

The change affects 1 system.

Changed systems: docs

Architecture concerns
No architecture-level concerns identified.

Review details

Systems and components

• observed — docs (service) was modified; 1 changed file maps to changed impact.

Before / after behavior

• observed — Modified behavior in docs/admins/maintenance/upgrades.md: Documents the landing page’s static 503 response from chart 2.4.0 when Envoy Gateway has no ready pod, and the maintenancePage.enabled: false setting for other routers.
• observed — Modified behavior in docs/admins/maintenance/upgrades.md: Documents that the landing page and REST service start replacement pods before stopping old ones and drain for 10 seconds; with two replicas each, they tolerate a node loss and have a PodDisruptionBudget. On a single-node cluster, disabling podDisruptionBudget.enabled avoids kubectl drain hanging.
• observed — Modified behavior in docs/admins/maintenance/upgrades.md: Adds commands to scale the landing page to zero and back for planned maintenance. States that a subsequent Helm upgrade restores it, and that the maintenance page affects only the landing page, not REST service errors or running sessions.

🚥 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 documentation changes: the maintenance page and rolling updates for chart 2.4.0.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
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.

✨ Finishing Touches

🧪 Generate unit tests (beta)

• Commit to this branch
• Create a new PR

---

Thanks for using CodeRabbit! It's free for OSS, and your support helps us grow. If you like it, consider giving us a shout-out.

❤️ Share

• X
• Mastodon
• Reddit
• LinkedIn

_{Comment @coderabbitai help to get the list of available commands.}