I've got a project where several pi's run NFS servers and export a directory (one each).
Another pi then mounts these directories, and exports them on its own NFS server.
A laptop then mounts these over direct wifi connection to the 'head' pi. The idea being that the laptop only has to make one connection to access files on all the 'sub' pi's.
To keep things simple to start with, I've only connected one 'sub' pi to the head pi.
The head pi mounts this share fine, and both boot without issue.
When I first install and start the NFS server on the head pi, it successfully exports the slave's shared directory, and everything's accessible via laptop.
But having done this, when I restart the pi's (unplug the power, the pi's are networked over a USB hub, and powering off the head pi powers off everything), the head pi won't boot again.
I assume that the NFS server on the head pi is attempting to export the sub-pi's directory before the sub-pi has booted, and getting stuck.
Is there a way to either re-order how things start at boot, or to get the head pi to wait for the sub-pi's export to become available before it starts its nfs server?
Failing that, is there a way to get some sort of diagnostic output so I can be absolutely sure of what's going on?