Expand "Configure a lifecycle policy" docs (#1906)

This PR takes a chunk out of internal issue [Requested fixes for data
lifecycle
docs](elastic/docs-content-internal#4) that
was initiated by a review of the ILM docs by our Support team.

It updates the "Configure a lifecycle policy" page to:

 - Add Kibana steps where we currently show only the API steps.
- In particular, when creating an index template users aren't always
sure what to specify on the "Index settings" tab, so this adds an
example config.
 - Add a page overview
 - Add a section about viewing the ILM status for an index or datastream
 - Fix up smaller items, such as:
    -  Explicitly call out the Kibana "Data retention" option.
- Emphasize that lifecycle phase changes are based on time since
rollover rather than index creation time
- Warn about updating the `logs@lifecycle` and `metrics@lifecycle`
policies since they affect a LOT of indices.
- Provide links for things like the index lifecycle actions, mappings,
etc., to help people understand these options.
 
**Please see preview pages**: 
- [Configure a lifecycle
policy](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/1906/manage-data/lifecycle/index-lifecycle-management/configure-lifecycle-policy)
- [Apply a lifecycle policy to an
index](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/1906/manage-data/lifecycle/index-lifecycle-management/policy-apply)
- [View the lifecycle status of an
index](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/1906/manage-data/lifecycle/index-lifecycle-management/policy-view-status)
- [Update or switch a lifecycle
policy](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/1906/manage-data/lifecycle/index-lifecycle-management/policy-updates)

(For reference, here's the [original
version](https://www.elastic.co/docs/manage-data/lifecycle/index-lifecycle-management/configure-lifecycle-policy)
of the first page).

**ES Data Management team**, if any of you can please give this a
technical review I'd be very grateful! 🙏 The API instructions aren't
changed, with the exception that I added [this
section](https://docs-v3-preview.elastic.dev/elastic/docs-content/pull/1906/manage-data/lifecycle/index-lifecycle-management/configure-lifecycle-policy#view-lifecycle-status)
about calling the _ILM explain_ API. The Kibana steps are all new.

---------

Co-authored-by: Mary Gouseti <[email protected]>
Co-authored-by: Vlada Chirmicci <[email protected]>

Author: 3 people

manage-data/data-store/data-streams/modify-data-stream.md

@@ -214,11 +214,10 @@ To change a [dynamic index setting](elasticsearch://reference/elasticsearch/inde
 
 
 ::::{important}
-To change the `index.lifecycle.name` setting, first use the [remove policy API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-ilm-remove-policy) to remove the existing {{ilm-init}} policy. See [Switch lifecycle policies](../../lifecycle/index-lifecycle-management/configure-lifecycle-policy.md#switch-lifecycle-policies).
+To change the `index.lifecycle.name` setting, first use the [remove policy API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-ilm-remove-policy) to remove the existing {{ilm-init}} policy. See [Switch lifecycle policies](/manage-data/lifecycle/index-lifecycle-management/policy-updates.md#switch-lifecycle-policies).
 ::::
 
 
-
 ### Change a static index setting for a data stream [change-static-index-setting-for-a-data-stream]
 
 [Static index settings](elasticsearch://reference/elasticsearch/index-settings/index.md) can only be set when a backing index is created. You cannot update static index settings using the [update index settings API](https://www.elastic.co/docs/api/doc/elasticsearch/operation/operation-indices-put-settings).

manage-data/images/elasticsearch-reference-create-policy-downsample.png

@@ -390,7 +390,7 @@ When data reaches the `cold` or `frozen` phases, it is automatically converted t
 5. Restore indices from the searchable snapshots.
 
     1. Follow the steps to [specify the data tier based allocation inclusion rules](/manage-data/lifecycle/data-tiers.md#update-data-tier-allocation-rules).
-    2. Remove the associated ILM policy (set it to `null`). If you want to apply a different ILM policy, follow the steps to [Switch lifecycle policies](/manage-data/lifecycle/index-lifecycle-management/configure-lifecycle-policy.md#switch-lifecycle-policies).
+    2. Remove the associated ILM policy (set it to `null`). If you want to apply a different ILM policy, follow the steps to [Switch lifecycle policies](/manage-data/lifecycle/index-lifecycle-management/policy-updates.md#switch-lifecycle-policies).
     3. If needed, specify the alias for rollover, otherwise set it to `null`.
     4. Optionally, specify the desired number of replica shards.
 

manage-data/images/elasticsearch-reference-create-policy.png

@@ -68,12 +68,13 @@ For example, if you are indexing metrics data from a fleet of ATMs into Elastics
 You can create and manage index lifecycle policies through {{kib}}'s [Index Management](/manage-data/data-store/index-basics.md#index-management) UI or the [{{ilm-init}} APIs](https://www.elastic.co/docs/api/doc/elasticsearch/v8/group/endpoint-ilm). For more details on creating and managing index lifecycle policies refer to:
 
 * [Configure a lifecycle policy](/manage-data/lifecycle/index-lifecycle-management/configure-lifecycle-policy.md)
-* [Update a lifecycle policy](/manage-data/lifecycle/index-lifecycle-management/policy-updates.md)
+* [View the lifecycle status of an index](/manage-data/lifecycle/index-lifecycle-management/policy-view-status.md)
+* [Update or switch a lifecycle policy](/manage-data/lifecycle/index-lifecycle-management/policy-updates.md)
 * [Start and stop index lifecycle management](/manage-data/lifecycle/index-lifecycle-management/start-stop-index-lifecycle-management.md)
 * [Restore a managed data stream or index](/manage-data/lifecycle/index-lifecycle-management/restore-managed-data-stream-index.md)
 * [Customize built-in policies](/manage-data/lifecycle/index-lifecycle-management/tutorial-customize-built-in-policies.md)
 
-Default {{ilm}} policies are created automatically when you use {{agent}}, {{beats}}, or the {{ls}} {{es}} output plugin to send data to the {{stack}}.
+Default {{ilm}} policies are created automatically when you install an [Elastic Integration](integration-docs://reference/index.md), or when you use {{agent}}, {{beats}}, or the {{ls}} {{es}} output plugin to send data to the {{stack}}.
 
 ![index lifecycle policies](/manage-data/images/elasticsearch-reference-index-lifecycle-policies.png)
 

manage-data/images/elasticsearch-reference-create-template-wizard-my_template.png

@@ -22,7 +22,7 @@ Starting in Curator version 5.7, Curator ignores {{ilm-init}} managed indices.
 
 ## Apply policies to existing time series indices [ilm-existing-indices-apply]
 
-The simplest way to transition to managing your periodic indices with {{ilm-init}} is to [configure an index template](configure-lifecycle-policy.md#apply-policy-template) to apply a lifecycle policy to new indices. Once the index you are writing to is being managed by {{ilm-init}}, you can [manually apply a policy](configure-lifecycle-policy.md#apply-policy-multiple) to your older indices.
+The simplest way to transition to managing your periodic indices with {{ilm-init}} is to [configure an index template](configure-lifecycle-policy.md#apply-policy-template) to apply a lifecycle policy to new indices. Once the index you are writing to is being managed by {{ilm-init}}, you can [manually apply a policy](/manage-data/lifecycle/index-lifecycle-management/policy-updates.md) to your older indices.
 
 Define a separate policy for your older indices that omits the rollover action. Rollover is used to manage where new data goes, so isn’t applicable.