Bug 2050556

This bug was initially created as a copy of Bug #1924587

I am copying this bug because: 
It still applies.


Description of problem:

Currently the shutdown phase executes dracut-shutdown.service which unpacks the initramfs into /run/initramfs. Then plymouth-switch-root-initramfs.service executes and switches root to /run/initramfs and final shutdown operations execute.

Sometimes, the initramfs couldn't be unpacked properly, which leads to dropping into the following prompt (executed by "shutdown" binary once switch-root happened):
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
/shutdown: line 115: reboot: command not found
[  145.951127] dracut Warning: reboot failed!
dracut Warning: reboot failed!


[  145.953007] dracut Warning: 
dracut Warning: 


Generating "/run/initramfs/rdsosreport.txt"
You might want to save "/run/initramfs/rdsosreport.txt" to a USB stick or /boot
after mounting them and attach it to a bug report.

To get more debug information in the report,
reboot with "rd.debug" added to the kernel command line.

Dropping to debug shell.

shutdown:/# 
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

So far we got some customers hitting this or something similar (e.g. /usr/bin/multipath: command no found) in different scenarios:

1. Upon installation with a virtual DVD mounted on the iLO with low bandwidth between the ISO image and the iLO

  In this scenario, the issue is due to low bandwidth: dracut-shutdown has only 90 seconds to complete and this may not be enough, causing systemd to kill the cpio command executing and having missing binaries in /run/initramfs, causing the issue after switching root

2. Upon restarting VMWare guests: it's unclear which condition effectively happens here but it's very likely related to unpacking being killed as well on 90 seconds timeout


Version-Release number of selected component (if applicable):

dracut-049-95.git20200804.el8.x86_64 / plymouth-0.9.4-7.20200615git1e36e30.el8.x86_64


How reproducible:

ALWAYS with a "slow" DVD during installation
ALWAYS using the hack below

Steps to Reproduce:
1. Edit /usr/lib/dracut/dracut-initramfs-restore to delete "reboot" binary after extraction happens

Replace "exit 0" at the end of the script by this:
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------
rm /run/initramfs/usr/sbin/reboot
exit 1
-------- 8< ---------------- 8< ---------------- 8< ---------------- 8< --------

This mimics a timeout while cpio is running (binaries in /usr/sbin are the last ones being extracted).

2. Reboot the system

Actual results:

Emergency prompt

Expected results:

Automatic reboot if possible