Bump Open OnDemand to v4 & install apps in fatimage

[bertiethorpe]

• Upgrade Open OnDemand to v4 (from v3)
• Fixes fatimage not installing ondemand app packages
• Increases fatimage size to 20GB (from 15GB)

NB: The password for "code server app" sessions can be found using My Interactive Sessions > Session ID > connection.yml

Open Ondemand v4 adds a cluster status page:

[sjpb]

It also needs some notes in a comment about what testing has been carrried out on ondemand.

[sjpb]

Image build: https://github.com/stackhpc/ansible-slurm-appliance/actions/runs/17859483504

[sjpb]

Image builds failing with:

==> openstack.openhpc: TASK [dnf_repos : Install epel-release] ****************************************
==> openstack.openhpc: task path: /home/runner/work/ansible-slurm-appliance/ansible-slurm-appliance/ansible/roles/dnf_repos/tasks/set_repos.yml:22
==> openstack.openhpc: Friday 19 September 2025  13:30:05 +0000 (0:00:05.997)       0:00:54.961 ******
==> openstack.openhpc: fatal: ***: FAILED! => {
==> openstack.openhpc:     "changed": false,
==> openstack.openhpc:     "rc": 1,
==> openstack.openhpc:     "results": []
==> openstack.openhpc: }
==> openstack.openhpc: 
==> openstack.openhpc: MSG:
==> openstack.openhpc: 
==> openstack.openhpc: Failed to download metadata for repo 'OpenHPC': Cannot download repomd.xml: Cannot download repodata/repomd.xml: All mirrors were tried

[sjpb]

Looks like dnf_repos_password isn't being set. Run without deleting build VM on failure:
https://github.com/stackhpc/ansible-slurm-appliance/actions/runs/17860113047
[edit Apparently leafcloud s3 is struggling]

[sjpb]

Image build: https://github.com/stackhpc/ansible-slurm-appliance/actions/runs/17980798444

[sjpb]

OnDemand testing (on RL8):

• Monitoring: OK
• Status dashboard: OK
• Shell: OK (sinfo, module av)
• Files: OK
• Remote desktop: OK (in terminal: sinfo, module av)
• Code server: OK
• Jupyter notebook: OK
• Rstudio: OK

[sjpb]

See comment before this for testing