README tweaks

Author: jovial

README.md

@@ -59,11 +59,11 @@ unique set of homogenous nodes:
   `free --mebi` total * `openhpc_ram_multiplier`.
   * `ram_multiplier`: Optional.  An override for the top-level definition
   `openhpc_ram_multiplier`. Has no effect if `ram_mb` is set.
-  * `gres_autodetect`: Optional. The [auto detection mechanism](https://slurm.schedmd.com/gres.conf.html#OPT_AutoDetect) to use for the  generic resources. Note: you must still define the `gres` dictionary (see below) but you only need the define the `conf` key.
+  * `gres_autodetect`: Optional. The [auto detection mechanism](https://slurm.schedmd.com/gres.conf.html#OPT_AutoDetect) to use for the  generic resources. Note: you must still define the `gres` dictionary (see below) but you only need the define the `conf` key. See [GRES autodetection](#gres-autodetection) section below.
   * `gres`: Optional. List of dicts defining [generic resources](https://slurm.schedmd.com/gres.html). Each dict should define:
       - `conf`: A string with the [resource specification](https://slurm.schedmd.com/slurm.conf.html#OPT_Gres_1) but requiring the format `<name>:<type>:<number>`, e.g. `gpu:A100:2`. Note the `type` is an arbitrary string.
       - `file`: Omit if `gres_autodetect` is set. A string with the [File](https://slurm.schedmd.com/gres.conf.html#OPT_File) (path to device(s)) for this resource, e.g. `/dev/nvidia[0-1]` for the above example.
-    Note [GresTypes](https://slurm.schedmd.com/slurm.conf.html#OPT_GresTypes) must be set in `openhpc_config` if this is used.
+  Note [GresTypes](https://slurm.schedmd.com/slurm.conf.html#OPT_GresTypes) must be set in `openhpc_config` if this is used.
   * `features`: Optional. List of [Features](https://slurm.schedmd.com/slurm.conf.html#OPT_Features) strings.
   * `node_params`: Optional. Mapping of additional parameters and values for
   [node configuration](https://slurm.schedmd.com/slurm.conf.html#lbAE).
@@ -354,4 +354,23 @@ The RPMs will be created in ` /root/rpmbuild/RPMS/x86_64/`. The method to distri
 each compute node is out of scope of this document. You can either use a custom package repository
 or simply install them manually on each node with Ansible.
 
+#### Configuration example
+
+A configuration snippet is shown below:
+
+```yaml
+openhpc_cluster_name: hpc
+openhpc_nodegroups:
+  - name: general
+  - name: large
+    node_params:
+      CoreSpecCount: 2
+  - name: gpu
+    gres_autodetect: nvml
+    gres:
+      - conf: gpu:A100:2
+```
+for additional context refer to the GPU example in: [Multiple Nodegroups](#multiple-nodegroups).
+
+
 <b id="slurm_ver_footnote">1</b> Slurm 20.11 removed `accounting_storage/filetxt` as an option. This version of Slurm was introduced in OpenHPC v2.1 but the OpenHPC repos are common to all OpenHPC v2.x releases. [↩](#accounting_storage)