I want to have a Shell command action or a command line sensor to A) test whether the two storages are accessible (i.e. the NFS mount is present), and B) check the storage disk usage on each of the NFS mounts.
At the moment, I can’t even see these locations mounted anywhere (that I would expect) in the directory structure from the terminal:
Addons are separate containers.
It is like it is a completely different server.
Available commands between the HA container and the terminal addon container might also be different.
I now completely understand what is going on, and have learned something new.
The host system (which I accessed through the Proxmox console) correctly shows the mounted drives.
When running HAOS, the drives that are configured in the UI under “Settings → System → Storage → Network Drives” are NOT bind-mounted into the “homeassistant” docker container from the host. I guess they don’t need to be.
It seems that instead the mounted network storage drives are bind-mounted into the supervisor container (instead of the homeassistant container, which runs the frontend). This can be seen by first logging into the supervisor container and then showing the mounts: