[Internal]: Document Fleet ILM policy picker for integration namespaces

[vishaangelova]

Description

Document the Fleet UI/API feature that lets users assign an ILM policy to an integration namespace from Data retention settings in the integration policy editor.

This feature requires opt-in for dedicated namespace index templates ({namespace}@custom / namespace index templates). It is Stack-only (the UI control is not rendered on Serverless).

Related product work:

• Product outcome: [Fleet] Allow users to assign an ILM policy to an Integration kibana#258053
• Kibana PR: [Fleet] Allow assigning an ILM policy to an integration namespace kibana#275197
• Depends on namespace customization: [Fleet] Add namespace level customization for packages kibana#262568, [Fleet] Add UI for integration namespace customization kibana#269141
• Parent feature docs issue: [Internal]: Document Fleet feature: integration namespace index templates #6545 (core namespace customization docs are tracked separately; conflict tutorial: [Internal]: Add tutorial for resolving template conflicts when enabling integration namespace index templates #7683)

Why this is a separate docs issue

Namespace customization docs (#6545) and the overlapping-template tutorial (#7683) do not cover the ILM policy picker. The picker:

• Has its own release note (release_note:feature)
• Is unavailable on Serverless
• Overlaps with / may update the existing ILM tutorial Scenario 3 (manual index-template cloning for namespace-specific ILM)

Suggested documentation targets

Page	Action	Why
New page or section under Fleet data streams (ILM / retention)	Document assigning an ILM policy per (package, namespace) after namespace opt-in (UI + API)	Users discover the picker from the policy editor; need to understand it is namespace-scoped, not policy-scoped
reference/fleet/data-streams-namespace-custom.md	Follow-up when this ILM docs work lands: add a short note on the composed_of example that assigning an ILM policy inserts a Fleet-managed component template named {type}-{dataset}@namespace.{namespace} between {namespace}@custom and the data-stream @custom, plus a link to the new ILM docs	Users who inspect templates after using Data retention settings will see an extra entry that the current opt-in-only example does not show. Deferred so we do not link to docs that do not exist yet.
reference/fleet/data-streams-ilm-tutorial.md / data-streams-scenario3.md	Update Scenario 3 (or add a new scenario) to prefer the UI picker when available, and keep the clone-based path as legacy/fallback	Scenario 3 currently teaches cloning index templates to get namespace-specific ILM

Feature details (for authors)

Already captured in product PR / outcome; keep docs aligned with:

• Stored on the package installation as namespace_customization_settings: { [namespace]: { ilm_policy?: string } }
• Fleet-managed component template per (data stream, namespace): {type}-{dataset}@namespace.{namespace} with index.lifecycle.name, referenced from the namespace index template composed_of between {namespace}@custom and {type}-{dataset}@custom
• UI: ILM dropdown in Data retention settings, gated on namespace opt-in, manage_ilm, and non-serverless
• API: PUT kbn:/api/fleet/epm/packages/<pkg> with namespace_customization_settings (clear with {} for that namespace)

Additional behavior from #258053 / #275197 that authors should cover (not already implied by the bullets above):

• Shared setting: two package policies for the same package and namespace share one ILM assignment; different namespaces can use different policies
• Rollover: Fleet triggers a best-effort async rollover (fleet:sync_ilm_policy); changes apply to new backing indices after rollover, not retroactively to existing ones
• Create policies first: users must create ILM policies in Stack Management; the picker does not create them inline
• Non-goals for this feature (and docs): per–data-stream ILM in the Fleet UI, DSL support, inline ILM creation
• Precedence: if a user also sets index.lifecycle.name on the data-stream @custom template, that still wins over the Fleet-managed namespace ILM component template
• Known product caveat (check before documenting opt-out): kibana#280422 (open) — error when turning off dedicated namespace templates after an ILM was selected; document opt-out carefully until fixed

Which deployment methods does this change impact?

Elastic On-Prem and Cloud (Stack). Not available in the Serverless UI.

What Elastic Stack release is this request related to?

9.5

Point of contact

Main contact: @jillguyonnet

Stakeholders: @elastic/fleet

Docs owner / follow-up from: @vishaangelova (opened as follow-up while documenting #6545)

[github-actions]

Elastic Docs AI Menu

Check one box to run an AI workflow for this issue.

• Triage (docs-triage). Status: not started.
• Size the work (docs-size). Status: not started.
• Scope the docs work (docs-issue-scope). Status: not started.

Powered by GitHub Agentic Workflows and docs-actions. For more information, reach out to the docs team.