Remove support for deprecated xpack.telemetry configurations (#51142)

* Remove support for deprecated xpack.telemetry configurations

In 7.5, we moved telemetry to OSS and dropped the xpack prefix for the
telemetry plugin configuration options. We deprecated the usage of the
xpack prefix so any existing usage would trigger a warning at startup.

In 8.0, we remove support for the deprecated xpack prefix configs for
telemetry.

* Move telemetry settings into its own document

* Use external reference instead of anchor

* Update docs/migration/migrate_8_0.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Update docs/migration/migrate_8_0.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Update docs/settings/telemetry-settings.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Update docs/settings/telemetry-settings.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Update docs/settings/telemetry-settings.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Update docs/settings/telemetry-settings.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Update docs/settings/telemetry-settings.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Update docs/settings/telemetry-settings.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Update docs/settings/telemetry-settings.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Update docs/settings/telemetry-settings.asciidoc

Co-Authored-By: gchaps <33642766+gchaps@users.noreply.github.com>

* Remove depecrated xpack.telemetry.* config from xpack_main/index.js

Co-authored-by: Alejandro Fernández Haro <alejandro.haro@elastic.co>
Co-authored-by: Elastic Machine <elasticmachine@users.noreply.github.com>
Co-authored-by: Alejandro Fernández Haro <afharo@gmail.com>
Co-authored-by: gchaps <33642766+gchaps@users.noreply.github.com>

docs/migration/migrate_8_0.asciidoc

@@ -141,4 +141,13 @@ access level.
 been deprecated with warnings that have been logged throughout 7.x. Please use Kibana UI to re-generate the
 POST URL snippets if you depend on these for automated PDF reports.
 
+[float]
+=== Configurations starting with `xpack.telemetry` are no longer valid
+
+*Details:*
+The `xpack.` prefix has been removed for all telemetry configurations.
+
+*Impact:*
+For any configurations beginning with `xpack.telemetry`, remove the `xpack` prefix. Use {kibana-ref}/telemetry-settings-kbn.html#telemetry-general-settings[`telemetry.enabled`] instead.
+
 // end::notable-breaking-changes[]

docs/settings/telemetry-settings.asciidoc

@@ -0,0 +1,38 @@
+[[telemetry-settings-kbn]]
+=== Telemetry settings in Kibana
+++++
+<titleabbrev>Telemetry settings</titleabbrev>
+++++
+
+By default, Usage Collection (also known as Telemetry) is enabled. This
+helps us learn about the {kib} features that our users are most interested in, so we
+can focus our efforts on making them even better.
+
+You can control whether this data is sent from the {kib} servers, or if it should be sent 
+from the user's browser, in case a firewall is blocking the connections from the server. Additionally, you can decide to completely disable this feature either in the config file or in {kib} via *Management > Kibana > Advanced Settings > Usage Data*.
+
+See our https://www.elastic.co/legal/privacy-statement[Privacy Statement] to learn more.
+
+[float]
+[[telemetry-general-settings]]
+==== General telemetry settings
+
+`telemetry.enabled`:: *Default: true*.
+Set to `true` to send cluster statistics to Elastic. Reporting your
+cluster statistics helps us improve your user experience. Your data is never
+shared with anyone. Set to `false` to disable statistics reporting from any
+browser connected to the {kib} instance.
+
+`telemetry.sendUsageFrom`:: *Default: 'browser'*.
+Set to `'server'` to report the cluster statistics from the {kib} server.
+If the server fails to connect to our endpoint at https://telemetry.elastic.co/, it assumes
+it is behind a firewall and falls back to `'browser'` to send it from users' browsers
+when they are navigating through {kib}.
+
+`telemetry.optIn`:: *Default: true*.
+Set to `true` to automatically opt into reporting cluster statistics. You can also opt out through
+*Advanced Settings* in {kib}.
+
+`telemetry.allowChangingOptInStatus`:: *Default: true*.
+Set to `true` to allow overwriting the `telemetry.optIn` setting via the {kib} UI. 
+Note: When `false`, `telemetry.optIn` must be `true`. To disable telemetry and not allow users to change that parameter, use `telemetry.enabled`.

docs/setup/settings.asciidoc

@@ -463,3 +463,4 @@ include::{docdir}/settings/reporting-settings.asciidoc[]
 include::secure-settings.asciidoc[]
 include::{docdir}/settings/security-settings.asciidoc[]
 include::{docdir}/settings/spaces-settings.asciidoc[]
+include::{docdir}/settings/telemetry-settings.asciidoc[]

src/core/server/config/deprecation/core_deprecations.ts

@@ -128,13 +128,6 @@ export const coreDeprecationProvider: ConfigDeprecationProvider = ({
   renameFromRoot('optimize.lazyHost', 'optimize.watchHost'),
   renameFromRoot('optimize.lazyPrebuild', 'optimize.watchPrebuild'),
   renameFromRoot('optimize.lazyProxyTimeout', 'optimize.watchProxyTimeout'),
-  renameFromRoot('xpack.xpack_main.telemetry.config', 'telemetry.config'),
-  renameFromRoot('xpack.xpack_main.telemetry.url', 'telemetry.url'),
-  renameFromRoot('xpack.xpack_main.telemetry.enabled', 'telemetry.enabled'),
-  renameFromRoot('xpack.telemetry.enabled', 'telemetry.enabled'),
-  renameFromRoot('xpack.telemetry.config', 'telemetry.config'),
-  renameFromRoot('xpack.telemetry.banner', 'telemetry.banner'),
-  renameFromRoot('xpack.telemetry.url', 'telemetry.url'),
   // Monitoring renames
   // TODO: Remove these from here once the monitoring plugin is migrated to NP
   renameFromRoot('xpack.monitoring.enabled', 'monitoring.enabled'),

x-pack/legacy/plugins/xpack_main/index.js

@@ -23,11 +23,6 @@ export const xpackMain = kibana => {
     config(Joi) {
       return Joi.object({
         enabled: Joi.boolean().default(true),
-        telemetry: Joi.object({
-          config: Joi.string().default(),
-          enabled: Joi.boolean().default(),
-          url: Joi.string().default(),
-        }).default(), // deprecated
       }).default();
     },