[DOCS] Adds the 8.0.0-alpha1 release notes

docs/CHANGELOG.asciidoc

@@ -1,5 +1,5 @@
 [[release-notes]]
-= Release Notes
+= Release notes
 
 [partintro]
 --
@@ -19,3 +19,242 @@ This section summarizes the changes in each release.
 == {kib} 8.0.0-alpha1
 
 coming[8.0.0]
+
+The following changes are released for the first time in {kib} 8.0.0-alpha1. Review the changes, then use the <<upgrade-assistant,Upgrade Assistant>> to complete the upgrade.
+
+[float]
+[[breaking-changes-8.0.0]]
+=== Breaking changes
+
+Breaking changes can prevent your application from optimal operation and performance. Review the breaking changes, then mitigrate the impact to your appilication. 
+
+// tag::notable-breaking-changes[]
+
+[float]
+[[enterprise-search-change]]
+==== Enterprise Search changes
+
+[discrete]
+[[breaking-106307]]
+.Required security plugin in 8.0
+[%collapsible]
+====
+*Details* +
+Enterprise Search now requires that you enable X-Pack Security. For more information, refer to {kibana-pull}106307[#106307]
+
+*Impact* +
+Enable X-Pack Security.
+====
+
+[float]
+[[index-pattern-change]]
+==== Index pattern changes
+
+[discrete]
+[[breaking-35173]]
+.Removed support for time-based interval index patterns
+[%collapsible]
+====
+*Details* +
+Time-based interval index patterns were deprecated in 5.x. In 6.x, you could no longer create time-based interval index patterns, but they continued to function as expected. Support for these index patterns has been removed in 8.0. For more information, refer to {kibana-pull}35173[#35173]
+
+*Impact* +
+You must migrate your time_based index patterns to a wildcard pattern. For example, logstash-*. 
+====
+
+[float]
+[[operations-changes]]
+==== Operations changes
+
+[discrete]
+[[breaking-93835]]
+.Removed platform from archive root directory
+[%collapsible]
+====
+*Details* +
+For the `.tar.gz` and `.zip` archives, `platform` has been removed from the `root` folder name. For more information, refer to {kibana-pull}93835[#93835]
+
+*Impact* +
+The `root` folder name now appears as `kibana-8.0.0-SNAPSHOT-linux-aarch64.tar.gz -> kibana-8.0.0-SNAPSHOT`.
+====
+
+[discrete]
+[[breaking-90511]]
+.Removed default support for TLS v1.0 and v1.1
+[%collapsible]
+====
+*Details* +
+The default support for TLS v1.0 and v1.1 has been removed. For more information, refer to {kibana-pull}90511[#90511]
+
+*Impact* +
+To enable support, set the environment variable to `NODE_OPTIONS=--tls-min-1.0`.
+====
+
+[discrete]
+[[breaking-74424]]
+.Removed support for sysv init
+[%collapsible]
+====
+*Details* +
+Systems that don't have `service` aliased to use kibana.service are unable to use `service start kibana`. For more information, refer to {kibana-pull}74424[#74424]
+
+*Impact* +
+If your system doesn't have `service` aliased to use kibana.service, use `systemctl start kibana.service`.
+====
+
+[discrete]
+[[breaking-42353]]
+.Disabled response logging as a default
+[%collapsible]
+====
+*Details* +
+By default, responses are not logged. Previously, responses were logged if `logging.json` was set to `true`, `logging.dest` was specified, or a TTY was detected. For more information, refer to {kibana-pull}42353[#42353]
+
+*Impact* +
+To log responses, set `logging.events.response=*` in kibana.yml.
+====
+
+[float]
+[[reporting-changes-8.0.0-alpha1]]
+==== Reporting changes
+
+[discrete]
+[[breaking-52539]]
+.Removed legacy Reporting job params compatibility shim
+[%collapsible]
+====
+*Details* +
+*Reporting* is no longer compatible with POST URL snippets generated with {kib} 6.2.0 and earlier. For more information, refer to {kibana-pull}52539[#52539]
+
+*Impact* +
+If you use POST URL snippets to automatically generate PDF reports, regenerate the POST URL strings.
+====
+
+[float]
+[[rest-api-changes]]
+==== Security changes
+
+[discrete]
+[[breaking-47929]]
+.Removed `/api/security/v1/saml` route
+[%collapsible]
+====
+*Details* +
+The `/api/security/v1/saml` route has been removed and is reflected in the kibana.yml `server.xsrf.whitelist` setting, {es}, and the Identity Provider SAML settings. For more information, refer to {kibana-pull}47929[#47929]
+
+*Impact* +
+Use the `/api/security/saml/callback` route, or wait to upgrade to 8.0.0-alpha2 when the `/api/security/saml/callback` route breaking change is reverted. 
+====
+
+[discrete]
+[[breaking-41700]]
+.Reject legacy browsers by default
+[%collapsible]
+====
+*Details* +
+To provide the maximum level of protection for most installations, the csp.strict config is now enabled by default. Legacy browsers not supported by Kibana, such as IE11, are unable to access {kib} unless explicitly enabled. All browsers officially supported by Kibana do not have this issue. For more information, refer to {kibana-pull}41700[#41700]
+
+*Impact* +
+To enable support for legacy browsers, set `csp.strict: false` in kibana.yml.
+====
+
+[float]
+[[settings-changes-8.0.0-alpha1]]
+==== Settings changes
+
+[discrete]
+[[breaking-106061]]
+.Use new session timeout defaults 
+[%collapsible]
+====
+*Details* +
+The default values for the session timeout `xpack.security.session.{lifespan|idleTimeout}` settings have changed. For more information, refer to {kibana-pull}106061[#106061]
+
+*Impact* +
+Use the following default values:
+
+* `xpack.security.session.idleTimeout: 1h`
+* `xpack.security.session.lifespan: 30d`
+====
+
+[discrete]
+[[breaking-87114]]
+.Removed support for setting `server.host` to '0'
+[%collapsible]
+====
+*Details* +
+Support for configuring {kib} with `0` as the `server.host` has been removed. Please use `0.0.0.0` instead. For more information, refer to {kibana-pull}87114[#87114]
+
+*Impact* +
+You are now unable to use `0` as the `server.host`.
+====
+
+[discrete]
+[[breaking-38657]]
+.Removed `xpack.security.authProviders` and `xpack.security.public`
+[%collapsible]
+====
+*Details* +
+The `xpack.security.public` and `xpack.security.authProviders` settings have been removed. For more information, refer to {kibana-pull}38657[#38657]
+
+*Impact* +
+Use the `xpack.security.authc.saml.realm` setting.
+====
+
+[discrete]
+[[breaking-22696]]
+.Removed useUTC deprecation
+[%collapsible]
+====
+*Details* +
+The `logging.useUTC` setting has been removed. For more information, refer to {kibana-pull}22696[#22696]
+
+*Impact* +
+The default timezone is UTC. To change the timezone, set `logging.timezone: false` in kibana.yml. Change the timezone when the system, such as a docker container, is configured for a nonlocal timezone.  
+====  
+
+// end::notable-breaking-changes[]
+
+[float]
+[[deprecations-8.0.0]]
+=== Deprecations
+
+The following functionality is deprecated in 8.0.0, and will be removed in 9.0.0. Deprecated functionality does not have an immediate impact on your application, but we strongly recommend you make the necessary updates after you complete the upgrade.
+
+[discrete]
+[[deprecation-74424]]
+.Removed support for SysV init
+[%collapsible]
+====
+*Details* +
+Systems that don't have `service` aliased to use kibana.service are unable to use `service start kibana`. For more information, refer to {kibana-pull}74424[#74424]
+
+*Impact* +
+If your system doesn't have `service` aliased to use kibana.service, use `systemctl start kibana.service`.
+====
+
+[discrete]
+[[deprecation-33603]]
+.Removed `xpack:defaultAdminEmail` setting
+[%collapsible]
+====
+*Details* +
+The `xpack:default_admin_email` setting for monitoring use has been removed. For more information, refer to {kibana-pull}33603[#33603]
+
+*Impact* +
+Use the `xpack.monitoring.clusterAlertsEmail` in kibana.yml.
+====
+
+[float]
+[[enhancements-and-bug-fixes-v8.0.0]]
+=== Bug fix
+
+The 8.0.0-alpha1 release includes the following bug fix.
+
+Operations::
+* Moves systemd service to /usr/lib/systemd/system {kibana-pull}83571[#83571]
+
+//[[release-notes-8.0.0]]
+//== {kib} 8.0.0
+
+//coming::[8.0.0]