In setting up an embedded system, a Linux box needed to have a read-only root partition. However, the OS must be able to write to certain files (the drive was partitioned into /, /home, /tmp, /usr, /var with the only read-only being / ). So I created symbolic links to the following files:
/etc/mtab (linked to /proc/mounts/etc/mtab)
/etc/network/interfaces (linked to /var/network/interfaces)
/etc/resolv.conf (linked to /var/network/resolv.conf)
/etc/hostname (linked to /var/network/hostname)

All work except /etc/hostname. Whenever I create the symbolic link, the system does not boot or fails to boot all the way.
Does anyone know a fix or an alternative to symbolic links here? /etc/hostname must be writeable.

I was never able to find how to make the symbolic link, so I just wrote a simple script to remount the partition as rw, change the hostname, and remount the partition as ro.