Merge pull request #3 from stackhpc/slurm-docs-update

Describe sudo access and addditional s/w for slurm

docs/platforms/slurm.md

@@ -24,4 +24,26 @@ The Slurm platform provides a multi-node HPC environment based on the [Slurm wor
 #### Platform monitoring
 A [Grafana](https://grafana.com/oss/grafana/) dashboard for system monitoring is included in the platform, and is accessible from the platforms page. General current and historical system information is visible.
 
-Additionally, Open OnDemand presents monitoring dashboards for each Slurm job.
+Additionally, Open OnDemand presents monitoring dashboards for each Slurm job.
+
+#### Root access
+
+To get passwordless `sudo` to the login node, SSH as the `rocky` user instead of the `azimuth` user shown on the platform's details page.
+
+Other nodes can also be accessed as `rocky` by jumping through the login node, e.g.:
+
+    ssh -J rocky@$LOGIN_ADDR rocky@$NODE_ADDR
+
+where `$LOGIN_ADDR` is the login node's address shown on the platform's details page and the other node's addresses can be retrieved from the `/etc/hosts` file on the login node, e.g.:
+
+    ssh -J rocky@$LOGIN_ADDR cat /etc/hosts
+
+#### Additional software
+
+Software installed directly via `sudo` will be lost when the platform is upgraded, as upgrades are performed by reimaging all nodes with a new image.
+
+Where possible, it is preferable to package additional software for use via [apptainer](https://apptainer.org/) which is installed on all Slurm platforms. This supports both SIF and Docker/OCI container formats.
+
+Some software is also available via the EESSI pilot repository - follow instructions from [here](https://www.eessi.io/docs/using_eessi/setting_up_environment/).
+
+If these methods are not appropriate and the software has wide applicability, consider making a PR to the [Slurm appliance repository](https://github.com/stackhpc/caas-slurm-appliance) which builds images for the Slurm platforms. Additional Ansible tasks could be added to the [extras.yml](https://github.com/stackhpc/ansible-slurm-appliance/blob/main/ansible/extras.yml) playbook.