Current File : //usr/lib/dracut/modules.d/98dracut-systemd/dracut-shutdown.service.8

'\" t
.\"     Title: dracut-shutdown.service
.\"    Author: [see the "AUTHORS" section]
.\" Generator: DocBook XSL Stylesheets vsnapshot <http://docbook.sf.net/>
.\"      Date: 04/06/2024
.\"    Manual: dracut
.\"    Source: dracut
.\"  Language: English
.\"
.TH "DRACUT\-SHUTDOWN\&.S" "8" "04/06/2024" "dracut" "dracut"
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.\" * MAIN CONTENT STARTS HERE *
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.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)