Flesh out docs a bit more

Author: jovial

docs/mig.md

@@ -1,5 +1,22 @@
 # vGPU/MIG configuration
 
+This page details how to configure Multi Instance GPU (MIG) in Slurm.
+
+## Pre-requisites
+
+- Image built with cuda support. This should automatically recompile slurm against NVML.
+
+## Inventory
+
+Add relevant hosts to the ``vgpu`` group, for example in ```environments/<environment>/inventory/groups``:
+
+```
+[vgpu:children]
+cuda
+```
+
+## Configuration
+
 Use variables from the [stackhpc.linux.vgpu](https://github.com/stackhpc/ansible-collection-linux/tree/main/roles/vgpu) role.
 
 For example in: `environments/<environment>/inventory/group_vars/all/vgpu`:
@@ -15,3 +32,11 @@ vgpu_definitions:
 
 The appliance will use the driver installed via the ``cuda`` role. Use ``lspci`` to determine the PCI
 addresses.
+
+## compute_init
+
+Use the ``enable_vgpu`` metadata option to enable creation of mig devices on rebuild.
+
+## gres configuration
+
+TODO