Troubleshooting: Start reworking the main page, and general guidance

docs/admin/troubleshooting/docker-jcmd.rst

@@ -1,7 +1,7 @@
 .. _jcmd-docker:
 
 ===============================================
-Troubleshooting CrateDB on Docker with ``jcmd``
+Troubleshooting CrateDB with ``jcmd`` on Docker
 ===============================================
 
 You can find a lot of troubleshooting guides for Java applications out there on

docs/admin/troubleshooting/index.md

@@ -0,0 +1,74 @@
+(troubleshooting)=
+
+# Troubleshooting
+
+A collection of guides and tools for troubleshooting CrateDB.
+
+You will learn how to apply self-service measurements supporting you when
+observing problems with your CrateDB database cluster.
+If you need help from others, feel free to reach out to our community or
+commercial [support channels][support] any time.
+
+:::{tip}
+Relevant suggestions will support you to optimally gather and convey
+information about your database cluster, which helps others to get a
+rough orientation about its size, and other technical characteristics.
+Before [contacting support][support], you optimally have this information
+ready.
+:::
+
+:::{note}
+The guidelines may not exclusively be applicable for users of CrateDB Cloud,
+or when running CrateDB on a commercial contract, where additional
+communication channels apply.
+
+Independently from support channels and status, significant parts
+of the instructions outlined here will help our support engineers to discover
+any sort of problem with your CrateDB cluster much faster than asking
+individual questions, so we generally recommend to use
+this guideline as a checklist in all situations.
+:::
+
+
+## Introduction
+
+Many details about the status of your cluster is included within CrateDB's
+[system tables]. The `sys` schema includes synthetic read-only tables which
+can be queried to get statistical real-time information about the cluster's
+metadata, like information about nodes and shards. The [](#systables) section
+illustrates how to use them.
+
+The sections below include instructions about how to use the [crate-node]
+and [jcmd] utility and diagnosis programs, and information about
+using the [Java Flight Recorder] for [monitoring Java applications].
+
+
+## Instructions
+
+:::{todo}
+- 🚧 A concise step-by-step checklist could be provided here, with
+  optional tool support.
+- 🧹 The "table of contents" section below may be removed.
+:::
+
+
+:::{rubric} Table of contents
+:::
+
+:::{toctree}
+:maxdepth: 2
+
+using system tables <system-tables>
+using crate-node <crate-node>
+using jcmd on Docker <docker-jcmd>
+:::
+
+
+
+
+[crate-node]: inv:crate-reference#cli-crate-node
+[Java Flight Recorder]: https://en.wikipedia.org/wiki/JDK_Flight_Recorder
+[jcmd]: https://www.baeldung.com/running-jvm-diagnose
+[monitoring Java applications]: https://www.baeldung.com/java-flight-recorder-monitoring
+[support]: https://cratedb.com/support
+[system tables]: inv:crate-reference#system-information

docs/admin/troubleshooting/systables.rst → docs/admin/troubleshooting/system-tables.rst

@@ -1,9 +1,9 @@
 .. highlight:: psql
 .. _systables:
 
-===============================
-Troubleshooting with sys-tables
-===============================
+==================================
+Troubleshooting with system tables
+==================================
 
 CrateDB maintains a set of diagnostic tables in the **sys** schema. It
 currently consists of ten tables that provide an overview of the cluster state.