On Wed, Sep 6, 2017 at 7:59 AM, Tarmo Kuuse <[email protected]> wrote: > On Tuesday, September 5, 2017 at 1:45:05 AM UTC+3, Britton Kerin wrote: >> >> Any help modifying the above recipe or pointer to how to do it these >> days would be appreciated. > > > I just declare the root file system as read-only in fstab and create some > ramdisks for stuff that needs to be writable. > > LABEL=rootfs / ext4 ro,noatime,errors=remount-ro 0 1 > debugfs /sys/kernel/debug debugfs defaults 0 0 > tmpfs /var/log tmpfs defaults,noatime,nosuid,mode=0777,size=128M 0 0 > tmpfs /var/tmp tmpfs defaults,noatime,nosuid,size=16M 0 0 > tmpfs /tmp tmpfs defaults,noatime,nosuid,size=128M 0 0 > > Service generic-board-startup (a.k.a. /opt/scripts/boot/generic-startup.sh) > must run once with a writable root to set up a bunch of stuff (on later > boots it complains, but it doesn't seem to matter). After that you're stuck > hacking all the software which expects to be able to write to disk. For a > working network, "/etc/resolv.conf" needs symlinking to a writable location. > Many services expect to persistently store their stuff under "/var/lib". > > I've used tmpfiles.d to create required symlinks, e.g. > > $ cat /etc/tmpfiles.d/10-ro-symlinks.conf > L+ /etc/resolv.conf - - - - /var/run/symlinks/etc/resolv.conf > L+ /etc/ppp/resolv.conf - - - - /var/run/symlinks/etc/ppp/resolv.conf
Interesting. The question is why the way I used to do it ever worked. It did seem to though: could change files around and next boot they would be back to their original state. I never had to do anything special for /etc/resolv.conf or anything. Perhaps it was only ending up applying to /root or something. What I wish is that there was a way to tell the kernel "look, never actually sync this file because I don't care and I don't trust the underlying media, go ahead and gradually fill memory and die I don't care about that either because I'm going to hard boot you every 24 hours anyway". Britton -- For more options, visit http://beagleboard.org/discuss --- You received this message because you are subscribed to the Google Groups "BeagleBoard" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/beagleboard/CAC4O8c_u38Pstqm%3DTZGYBjm_E%2B1HndSSQyaN3WWU3wLp%3D2sgYg%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
