Since #104614 the top-level repo troubleshooting page is just a short
paragraph which talks about "this page" but in fact refers to
information spread across a number of subsequent pages. It's not obvious
to the reader that they need to use the navigation menu to get to the
information they seek. Moreover we link to this page from an exception
message today so there's a reasonable chance that users will find it
when trying to troubleshoot a genuine problem.
This commit rewords things slightly and adds links to the subsequent
pages to the body of the page to avoid this confusion.
* Remove `es-test-dir` book-scoped variable
* Remove `plugins-examples-dir` book-scoped variable
* Remove `:dependencies-dir:` and `:xes-repo-dir:` book-scoped variables
- In `index.asciidoc`, two variables (`:dependencies-dir:` and `:xes-repo-dir:`) were removed.
- In `sql/index.asciidoc`, the `:sql-tests:` path was updated to fuller path
- In `esql/index.asciidoc`, the `:esql-tests:` path was updated idem
* Replace `es-repo-dir` with `es-ref-dir`
* Move `:include-xpack: true` to few files that use it, remove from index.asciidoc
This PR extends the repository integrity health indicator to cover also unknown and invalid repositories. Because these errors are local to a node, we extend the `LocalHealthMonitor` to monitor the repositories and report the changes in their health regarding the unknown or invalid status.
To simplify this extension in the future, we introduce the `HealthTracker` abstract class that can be used to create new local health checks.
Furthermore, we change the severity of the health status when the repository integrity indicator reports unhealthy from `RED` to `YELLOW` because even though this is a serious issue, there is no user impact yet.
This troubleshooting guide is what will be returned from the SLM health indicator
when a SLM policy has suffered from too many repeat failures without a successful
execution.
