I’m wanting to make a custom build of VyOS that leverages the existing squashfs + persistance structure to be able to have a system image (transparently) read/write directories that will actually be on a separate partition.
Where is the configuration specified for the overlay/union-fs system that ties everything together? I’m seeing some details specified in the grub configuration but am not entirely sure that is the key config location.
With some more research, I was able to answer my own question. It appears that init in the script located at /usr/libexec/vyos/init/vyos-router is called sometime during boot which ties the squashfs image and the persistance partitions together with overlay/union-fs.