chesty/overlayroot

mounts an overlay file system over root

overlayroot's Issues

Scripts update for ODROID XU4 platform

There is a tiny problem on XU4 the /overlay/lower is not mounted read only.

/dev/mmcblk0p1 on /overlay/lower type ext4 (rw,relatime)

I think I must update partition name inside script (I post result here)...

XU4 mount :

(root|~) mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
udev on /dev type devtmpfs (rw,nosuid,relatime,size=953384k,nr_inodes=187412,mode=755)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,noexec,relatime,size=204488k,mode=755)
overlay on / type overlay (rw,relatime,lowerdir=/overlay/lower,upperdir=/overlay/upper,workdir=/overlay/work)
tmpfs on /overlay type tmpfs (rw,relatime)
/dev/mmcblk0p1 on /overlay/lower type ext4 (rw,relatime)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
tmpfs on /run/lock type tmpfs (rw,nosuid,nodev,noexec,relatime,size=5120k)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/lib/systemd/systemd-cgroups-agent,name=systemd)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_cls,net_prio)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpu,cpuacct)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=26,pgrp=1,timeout=0,minproto=5,maxproto=5,direct)
mqueue on /dev/mqueue type mqueue (rw,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
configfs on /sys/kernel/config type configfs (rw,relatime)
tmpfs on /tmp type tmpfs (rw,nosuid,relatime)
overlay on /var/log.hdd type overlay (rw,relatime,lowerdir=/overlay/lower,upperdir=/overlay/upper,workdir=/overlay/work)
/dev/zram0 on /var/log type ext4 (rw,relatime,block_validity,discard,delalloc,nojournal_checksum,barrier,user_xattr,acl)
tmpfs on /run/user/0 type tmpfs (rw,nosuid,nodev,relatime,size=204484k,mode=700)

Missing mounts after "rootwork"

Whenever i connect to the Raspberry Pi with "overlayroot" thru SSH, run "rootwork", "exit" and then
disconnect, i cannot SSH again, i get this error.

ubuntu@DESKTOP:~$ ssh [email protected]
[email protected]'s password:
PTY allocation request failed on channel 0

After exiting "rootwork" /dev/pts/0 is not there anymore.

Before rootwork

pi@raspberrypiB:~ $ grep --color devpts /proc/mounts
devpts /dev/pts devpts rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000 0 0

After rootwork

pi@raspberrypiB:~ $ grep --color devpts /proc/mounts
pi@raspberrypiB:~ $

I can only SSH again if i manually reboot it.

I've made a pull request with the fix for this.

Mounting /boot read-only

I noticed in rootwork that the /boot partition is remounted rw and then ro on exit, but I don't see where /boot is mounted ro to begin with. On Rasbian, is the /boot partition actually mounted ro after a reboot but before running rootwork?

Just a note - mounting /boot as ro may not be that important because nothing should write to it during normal operation, only during things like kernel updates. However, I don't know what risk power failures would pose.

Related to this, to support Ubuntu Server and other systems that use /boot/firmware rather than /boot (see issue #9), the rootwork script needs to be updated - perhaps to use /boot/firmware if it is a mountpoint, and otherwise use /boot.

@chesty - I want to add to others' comments about how valuable this project is for long-term RPi stable operation. We appreciate the time and energy you've contributed to write, test, publish, and support this project.

Uninstall guide

How do I uninstall this? Might be worth putting in the README.

chroot conflicts with systemd

The chrooting solution is great, however it should be mentioned in the readme, that it has issues with systemd:

- can't reboot
# reboot
Running in chroot, ignoring request.

- can't list active services
# systemctl
Running in chroot, ignoring command 'list-units'

- we cannot be sure, if a new package has been installed succesfully
# apt-get install dbus
E: Can not write log (Is /dev/pts mounted?) - posix_openpt (19: No such device)
Running in chroot, ignoring request / command 'daemon-reload' / 'show' / 'daemon-reload' / 'is-active'
.......service is a disabled or a static unit, not starting it.

If such a task is required I suggest commenting out the initramfs= in /boot/config.txt temporally and reboot.

Create a tag so there is a known stable point

Hey - thanks for this I'm currently testing it out on a Raspberry Pi Zero W running DietPi.

I know this repo has been stable for a long time now but I was wondering if we could create a tag / "release". So that if I install this on multiple Pis I don't have to just clone master which always risks moving on. It would be much better to be able to clone a tag or a release to ensure all versions are the same.

Thanks.

/overlay/lower file not found.

My system work perfectly in RO. but there is a strange bug inside the bashscript at 32 (chroot line)

${SUDO} IMCHROOTED=${ROOT} chroot ${ROOT}

(it's my own PS1)

(root|~/overlayroot) ./rootwork
./rootwork: ligne 32: IMCHROOTED=/overlay/lower: Aucun fichier ou dossier de ce type

I must remove the IMCHROOTED=${ROOT} before the chroot on line 32 to get the RW chroot.

on an read-only root

My pi boot by nfs from a piserver, and I want to use overlayroot to set root writable. I succeed on the os from piserver (kernel version: 4.19.97-v7+), but failed on the latest raspberry pi os (kernel version: 5.4.51-v7l+).
I set debug option on cmdline.txt to see the initramfs debug, and found the error occurred on init-bottom-overlay script from line 64:
mount -t overlay overlay -olowerdir=/overlay/lower,upperdir=/overlay/upper,workdir=/overlay/work ${rootmnt}
mount: mount overlay on /root failed: No such device.
cp: can't stat '/root/etc/fstab': No such file or directory.
/script/init-bottom/init-bottom-overlay: line 71: can't create /root/etc/fstab: nonexistent directory.
/script/init-bottom/init-bottom-overlay: line 72: can't create /root/etc/fstab: nonexistent directory.

Should it work with centos ?

Hello,

Can we use it with CentOS ?

Thanks,
ran

It not work on latest pi os

I tried again and again with the latest pi os 2020-08-20 with kernel 5.4.51-v7l+.

Not working on Ubuntu Server

I have been unable to get this working on Ubuntu 18.04 Server on a Raspberry Pi 3.

As far as I can tell, everything is installed correctly (note Ubuntu uses /boot/firmware rather than /boot):

$ uname -a
Linux rpi3 4.15.0-1048-raspi2 #52-Ubuntu SMP PREEMPT Wed Sep 18 08:58:33 UTC 2019 armv7l armv7l armv7l GNU/Linux

$ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 18.04.3 LTS
Release:	18.04
Codename:	bionic

$ mount |grep mmc
/dev/mmcblk0p2 on / type ext4 (rw,relatime,data=ordered)
/dev/mmcblk0p1 on /boot/firmware type vfat (rw,relatime,fmask=0022,dmask=0022,codepage=437,iocharset=ascii,shortname=mixed,errors=remount-ro)

$ grep initramfs /boot/firmware/config.txt 
#initramfs initrd.img followkernel
initramfs initrd.gz followkernel

$ grep overlay /etc/initramfs-tools/modules
overlay

$ ls -al /etc/initramfs-tools/hooks/hooks-overlay /etc/initramfs-tools/scripts/init-bottom/init-bottom-overlay
-rwxr-xr-x 1 root root  324 Oct 21 14:26 /etc/initramfs-tools/hooks/hooks-overlay
-rwxr-xr-x 1 root root 1973 Oct 21 14:30 /etc/initramfs-tools/scripts/init-bottom/init-bottom-overlay

$ ls -al /boot/firmware/init.gz 
-rwxr-xr-x 1 root root 18609106 Oct 21 15:14 /boot/firmware/init.gz

$ ls -al /usr/share/initramfs-tools/scripts/functions /usr/share/initramfs-tools/hook-functions
-rw-r--r-- 1 root root 22234 Apr 17  2019 /usr/share/initramfs-tools/hook-functions
-rw-r--r-- 1 root root 20067 Dec 12  2018 /usr/share/initramfs-tools/scripts/functions

$ 

However, after rebooting, there is no sign that init-bottom-overlay is even being run:

$ ls -al / |grep overlay

$ cat /var/log/syslog |grep overlay

$ mount |grep overlay

$ cat /proc/cmdline |grep overlay

$ cat /etc/fstab |grep overlay

$ 

Issues with Ubuntu for ARM

I tried this with the DE10-nano board running the provided LXDE Ubuntu 16.04 image (login needed to get it -
https://download.terasic.com/downloads/cd-rom/de10-nano/linux_BSP/DE10_Nano_LXDE.zip).

I followed all the steps for Ubuntu ARM but nothing seems to happen after rebooting. /overlay/lower is not even created and of course all changes are NOT lost after rebooting again.

I can see the prompt changing though (with an 'RO' at the end). Executing 'rootwork' confirms that there is no overlay (it says there is no /overlay). How can I debug this issue? It seems like the scripts are not executing. I noticed that the Ubuntu Linux comes with not fstab file. The bootloader is in charge of mounting the / partition here. I created an fstab file for the command 'sudo update-initramfs -k $(uname -r) -u' to work. I also noticed that the fstab file is not modified at all. Is this supposed to happen? I am sure that I created the fstab file correctly. The is a fat partition that is now mounted fine by the fstab.

I have access to the bootloader code if anything could be changed to that to make overlayroot work. Any ideas?

How to undo all changes made, to make system partitions be as before installing overlayroot?

I read in a previous issue:

Just comment out "initramfs init.gz" in "/boot/config.txt".

But that did not work. Is it possible to undo all changes made to the partitions to make the system be as previously? If so, how?

Edit:
My main guess is that the fstab file needs to be changed as well. Right now mine is as following:
overlay / overlay rw,relatime,lowerdir=/overlay/lower,upperdir=/overlay/upper,workdir=/overlay/work 0 0

But I did not make a copy of the original fstab, so is it then not possible to revert this overlay state?

Complete install script for raspberry pi?

First thank you for your work, this seems like a robust solution for read only overlayed root fs for raspberry. I was wondering if you'd be interested to provide an install script that would do all the work? If yes, I think I can make a pull request. My skills in bash are limited so you will need to look at it...
Sounds like a good idea?