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Edit File: dracut-shutdown.service.8

'\" t .\" Title: dracut-shutdown.service .\" Author: [see the "AUTHORS" section] .\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/> .\" Date: 10/14/2023 .\" Manual: dracut .\" Source: dracut .\" Language: English .\" .TH "DRACUT\-SHUTDOWN\&.S" "8" "10/14/2023" "dracut" "dracut" .\" ----------------------------------------------------------------- .\" * Define some portability stuff .\" ----------------------------------------------------------------- .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .\" http://bugs.debian.org/507673 .\" http://lists.gnu.org/archive/html/groff/2009-02/msg00013.html .\" ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ .ie \n(.g .ds Aq \(aq .el .ds Aq ' .\" ----------------------------------------------------------------- .\" * set default formatting .\" ----------------------------------------------------------------- .\" disable hyphenation .nh .\" disable justification (adjust text to left margin only) .ad l .\" ----------------------------------------------------------------- .\" * MAIN CONTENT STARTS HERE * .\" ----------------------------------------------------------------- .SH "NAME" dracut-shutdown.service \- unpack the initramfs to /run/initramfs .SH "SYNOPSIS" .sp dracut\-shutdown\&.service .SH "DESCRIPTION" .sp This service unpacks the initramfs image to /run/initramfs\&. systemd pivots into /run/initramfs at shutdown, so the root filesystem can be safely unmounted\&. .sp The following steps are executed during a shutdown: .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} systemd switches to the shutdown\&.target .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} systemd starts /lib/systemd/system/shutdown\&.target\&.wants/dracut\-shutdown\&.service .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} dracut\-shutdown\&.service executes /usr/lib/dracut/dracut\-initramfs\-restore which unpacks the initramfs to /run/initramfs .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} systemd finishes shutdown\&.target .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} systemd kills all processes .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} systemd tries to unmount everything and mounts the remaining read\-only .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} systemd checks, if there is a /run/initramfs/shutdown executable .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} if yes, it does a pivot_root to /run/initramfs and executes \&./shutdown\&. The old root is then mounted on /oldroot\&. /usr/lib/dracut/modules\&.d/99shutdown/shutdown\&.sh is the shutdown executable\&. .RE .sp .RS 4 .ie n \{\ \h'-04'\(bu\h'+03'\c .\} .el \{\ .sp -1 .IP \(bu 2.3 .\} shutdown will try to umount every /oldroot mount and calls the various shutdown hooks from the dracut modules .RE .sp This ensures, that all devices are disassembled and unmounted cleanly\&. .sp To debug the shutdown process, you can get a shell in the shutdown procedure by injecting "rd\&.break=pre\-shutdown rd\&.shell" or "rd\&.break=shutdown rd\&.shell"\&. .sp .if n \{\ .RS 4 .\} .nf # mkdir \-p /run/initramfs/etc/cmdline\&.d # echo "rd\&.break=pre\-shutdown rd\&.shell" > /run/initramfs/etc/cmdline\&.d/debug\&.conf # touch /run/initramfs/\&.need_shutdown .fi .if n \{\ .RE .\} .sp In case the unpack of the initramfs fails, dracut\-shutdown\-onfailure\&.service executes to make sure switch root doesn\(cqt happen, since it would result in switching to an incomplete initramfs\&. .SH "AUTHORS" .sp Harald Hoyer .SH "SEE ALSO" .sp \fBdracut\fR(8)