raspbian-ua-netinst-ro

An installation of debian that creates a read only system

Intended to be used with raspbian-ua-netinst

Basically, what happens is that /var gets moved to /var_orig, /var_rw is created and mounted as a tmpfs. After this a unionfs is created, so reads from /var really are "served" from /var_orig, and writes go to /var_rw. In case anything is written to a location, it's read from the *_rw location.

Possible improvements:

• Disable journal
• create writable partitions, so state is preserved, add a boot time check to recreate the filesystem if a problem is found with the writable partitions
• mount_unionfs could be made in a more robust fashion
• /var_orig should be cleaned out as much as possible
• write scripts to remount the system read-write and back to read-only
• Documentation
• ...

Contributions are welcome, of course 😉

Temporarily enable write:

One can issue the following command (same thing for /boot) to gain temporary write access to the filesystem (note that /var will still be mounted in a tmpfs, so changes there will be lost!):

(sudo) mount -o remount,rw /

when done writing changes, remount it ro again:

(sudo) mount -o remount,ro /