Dracut needs /proc and /dev mounts

[Vogtinator]

Using python3-kiwi-9.23.31-1.1, the generated initrd is incomplete because dracut fails to run some commands due to missing mounts:

[  116s] [ DEBUG   ]: 22:30:05 | EXEC: [chroot /usr/src/packages/KIWI-vmx/build/image-root dracut --verbose --no-hostonly --no-hostonly-cmdline --xz --install /.profile --omit  multipath  --install /config.partids openSUSE-MicroOS.x86_64-16.0.0.initrd.xz 5.12.12-1-default]
[  191s] [ DEBUG   ]: 22:31:20 | findmnt: can't read /proc/mounts: No such file or directory
[  191s] dracut: Executing: /usr/bin/dracut --verbose --no-hostonly --no-hostonly-cmdline --xz --install /.profile --omit " multipath " --install /config.partids openSUSE-MicroOS.x86_64-16.0.0.initrd.xz 5.12.12-1-default
...
[  191s] dracut: *** Including module: systemd ***
[  191s] /usr/lib/dracut/modules.d/00systemd/module-setup.sh: line 168: /dev/fd/63: No such file or directory
...
[  191s] dracut: *** Including module: url-lib ***
[  191s] /usr/lib/dracut/modules.d/45url-lib/module-setup.sh: line 35: /dev/fd/63: No such file or directory
[  191s] /usr/lib/dracut/modules.d/45url-lib/module-setup.sh: line 37: /dev/fd/63: No such file or directory
[  191s] /usr/lib/dracut/modules.d/45url-lib/module-setup.sh: line 35: /dev/fd/63: No such file or directory
[  191s] /usr/lib/dracut/modules.d/45url-lib/module-setup.sh: line 37: /dev/fd/63: No such file or directory
[  191s] /usr/lib/dracut/modules.d/45url-lib/module-setup.sh: line 35: /dev/fd/63: No such file or directory
[  191s] /usr/lib/dracut/modules.d/45url-lib/module-setup.sh: line 37: /dev/fd/63: No such file or directory
[  191s] /usr/lib/dracut/modules.d/45url-lib/module-setup.sh: line 35: /dev/fd/63: No such file or directory
[  191s] /usr/lib/dracut/modules.d/45url-lib/module-setup.sh: line 37: /dev/fd/63: No such file or directory
[  191s] dracut: Couldn't find SSL CA cert bundle or libnssckbi.so; HTTPS won't work.
...
[  191s] dracut: *** Including module: kernel-modules-extra ***
[  191s] dracut:   kernel-modules-extra: configuration source "/run/depmod.d" does not exist
[  191s] dracut:   kernel-modules-extra: configuration source "/lib/depmod.d" does not exist
[  191s] /usr/lib/dracut/modules.d/90kernel-modules-extra/module-setup.sh: line 77: /dev/fd/63: No such file or directory
[  191s] dracut:   kernel-modules-extra: parsing configuration file "00-system.conf//etc/depmod.d/00-system.conf"
[  191s] /usr/lib/dracut/modules.d/90kernel-modules-extra/module-setup.sh: line 82: 00-system.conf//etc/depmod.d/00-system.conf: No such file or directory

[schaefi]

Hmm, it looks up stuff in /dev and /proc on the host the image is created on. I fear even if we mount this it could lead to wrong results. dracut is called in "--no-hostonly" mode, can we first clarify what it looks up on the host ?

You said the generated initrd is incomplete, what exactly is missing that harms on the image when used as such later on ?
and does it really require us to mount host filesystems when creating a no-host-only initrd ?

Thanks

[Vogtinator]

Bash needs /dev/fd/XX for expressions such as cat <(echo hi). So without /dev/ being present, core bash features are simply not working.

[schaefi]

makes sense and let me wonder why it was not an issue before... I'll check on the code

[Vogtinator]

I guess that before the update to dracut 55, it didn't make use of that feature or only in places where it didn't cause any issues.

[schaefi]

PR open for review

[Vogtinator]

Hmm, it looks up stuff in /dev and /proc on the host the image is created on. I fear even if we mount this it could lead to wrong results. dracut is called in "--no-hostonly" mode, can we first clarify what it looks up on the host ?

I think this particular error message is just from checking whether /tmp is mounted noexec, which should be fine. There are various other places where dracut calls findmnt to look at /proc/self/mounts, but in theory those should be unused in non-hostonly mode.