docs: explain RacksDB is now optional

Explain RacksDB is now optional in quickstart guide, with method to
disable integration feature in side note, and in overview and
architecture pages.

CHANGELOG.md

@@ -25,7 +25,10 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
     cluster (#418→#434).
 - conf: Update description of `agent` > `racksdb_version` to describe its new
   semantic.
-- docs: Update configuration reference documentation.
+- docs:
+  - Explain RacksDB is now optional in quickstart guide, with method to disable
+    integration feature in side note, and in overview and architecture pages.
+  - Update configuration reference documentation.
 
 ### Fixed
 - agent: Fix No module named 'werkzeug.middleware' ModuleNotFoundError with

docs/modules/install/pages/quickstart.adoc

@@ -287,43 +287,6 @@ INFO ⸬ Setting read permission on key for slurm user
 * xref:usage:manpages/slurm-web-gen-jwt-key.adoc[`slurm-web-gen-jwt-key` command manpage]
 --
 
-[#racksdb]
-== RacksDB database
-
-Slurm-web uses xref:racksdb:overview:start.adoc[RacksDB] to generate graphical
-representation of datacenters racks with the compute nodes. RacksDB database
-must be defined with your HPC cluster infrastructure. This is actually quick and
-easy easy based on
-xref:racksdb:install:quickstart.adoc#examples[the examples provided].
-
-Some requirements must be fulfilled in this database:
-
-* The infrastructure must have the same name as the cluster
-  <<_initial_setup,previously declared>> in _agent_ configuration file.
-* The _compute_ tag must be assigned to all compute nodes declared in Slurm
-  configuration.
-
-[NOTE]
-====
-You can choose other tag name but you will have to declare this tag in
-xref:conf:conf/agent.adoc#_racksdb[`racksdb` section of agent configuration],
-for example:
-
-[source,ini]
-----
-[racksdb]
-tags=blade
-----
-====
-
-[sidebar]
---
-.More links
-* xref:racksdb:overview:start.adoc[RacksDB reference documentation]
-* xref:racksdb:install:quickstart.adoc[RacksDB quickstart guide]
-* xref:racksdb:db:structure.adoc[RacksDB database structure reference]
---
-
 == First Access
 
 Slurm-web is now ready to start! Enable and start the _agent_ and _gateway_
@@ -639,6 +602,58 @@ xref:misc:troubleshooting.adoc#wsgi[troubleshooting guide] for help.
 * xref:conf:wsgi/index.adoc[Production HTTP server setup guide].
 ****
 
+[#racksdb]
+== RacksDB database (optional)
+
+Slurm-web can use xref:racksdb:overview:start.adoc[RacksDB] to generate
+xref:overview:overview.adoc#nodes-status[advanced interactive graphical representations]
+of datacenters racks with the compute nodes. For this feature, RacksDB database
+must be defined with your HPC cluster infrastructure. This is actually quick and
+easy easy based on
+xref:racksdb:install:quickstart.adoc#examples[the examples provided].
+
+Some requirements must be fulfilled in this database:
+
+* The infrastructure must have the same name as the cluster
+  <<_initial_setup,previously declared>> in _agent_ configuration file.
+* The _compute_ tag must be assigned to all compute nodes declared in Slurm
+  configuration.
+
+[NOTE]
+====
+You can choose other tag name but you will have to declare this tag in
+xref:conf:conf/agent.adoc#_racksdb[`racksdb` section of agent configuration],
+for example:
+
+[source,ini]
+----
+[racksdb]
+tags=blade
+----
+====
+
+[NOTE]
+====
+If you don't need this
+xref:overview:overview.adoc#nodes-status[advanced interactive graphical representations]
+feature, RacksDB integration can be completely disabled with the following lines
+in [.path]#`/etc/slurm-web/agent.ini`#:
+
+[source,ini]
+----
+[racksdb]
+enabled=no
+----
+====
+
+[sidebar]
+--
+.More links
+* xref:racksdb:overview:start.adoc[RacksDB reference documentation]
+* xref:racksdb:install:quickstart.adoc[RacksDB quickstart guide]
+* xref:racksdb:db:structure.adoc[RacksDB database structure reference]
+--
+
 == Metrics (optional)
 
 Slurm-web offers the possibility to

docs/modules/overview/pages/architecture.adoc

@@ -43,18 +43,20 @@ OpenLDAP, FreeIPA and Active Directory with legacy NIS and RFC 2307 bis schemas.
 
 The *agent* component reads the
 xref:conf:policy.adoc[RBAC autorization policy] from a plain INI file with
-permissions associated to roles and LDAP groups. The component also extracts
-cluster racking topology from xref:racksdb:overview:start.adoc[RacksDB] database
-to generate
-xref:overview.adoc#nodes-status[graphical representation of nodes status] in the
-racks.
-
-Optionally, the *agent* can connect to https://redis.io/[Redis] in-memory
-key/value database to save cached data from Slurm. It can also integrate with
-https://prometheus.io/[Prometheus] (or compatible) by exporting
-xref:overview.adoc#metrics[various Slurm metrics] for storage in timeseries
-database. The agent can then query this database to get historical values of
-these metrics.
+permissions associated to roles and LDAP groups.
+
+Optionally, the *agent* can also:
+
+- Extract cluster racking topology from
+  xref:racksdb:overview:start.adoc[RacksDB] database to generate
+  xref:overview.adoc#nodes-status[interactive graphical representation of nodes status]
+  in the racks.
+- Connect to https://redis.io/[Redis] in-memory key/value database to
+  xref:overview.adoc#cache[save cached data] from Slurm.
+- Integrate with https://prometheus.io/[Prometheus] (or compatible) by exporting
+  xref:overview.adoc#metrics[various Slurm metrics] for storage in timeseries
+  database. The agent can then query this database to get historical values of
+  these metrics.
 
 [#protocols]
 == Protocols

docs/modules/overview/pages/overview.adoc

@@ -60,8 +60,10 @@ Watch your jobs running with visual representation of their progress.
 [#nodes-status]
 == Nodes Status
 
-Live status of the compute nodes is displayed in a graphical representation of
-the racks. Just move the mouse pointer over a specific node to get all details:
+Live status of the compute nodes can be visualized in an advanced interactive
+graphical representation of the racks based on data extracted from
+xref:racksdb:overview:start.adoc[RacksDB]. Just move the mouse pointer over a
+specific node to get all details:
 
 image::screenshot_nodes_hovering.png[]