'\" t
.TH "SYSTEMD\-DEBUG\-GENERATOR" "8" "" "systemd 259" "systemd-debug-generator"
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.SH "NAME"
systemd-debug-generator \- Generator for enabling a runtime debug shell and masking specific units at boot
.SH "SYNOPSIS"
.PP
/usr/lib/systemd/system\-generators/systemd\-debug\-generator
.SH "DESCRIPTION"
.PP
\fBsystemd\-debug\-generator\fR
is a generator that provides some debugging functionality\&.
.PP
\fBsystemd\-debug\-generator\fR
implements
\fBsystemd.generator\fR(7)\&.
.SH "KERNEL COMMAND LINE"
.PP
\fBsystemd\-debug\-generator\fR
understands the following kernel command line parameters:
.PP
\fIsystemd\&.mask=\fR, \fIrd\&.systemd\&.mask=\fR
.RS 4
These options take a unit name as argument\&. The unit specified is masked for the runtime (i\&.e\&. for this session \(em from boot to shutdown), similarly to the effect of
\fBsystemctl\fR(1)\*(Aqs
\fBmask\fR
command\&. This is useful to boot with certain units removed from the initial boot transaction for debugging system startup\&. May be specified more than once\&. The option prefixed with
"rd\&."
is honored only in the initrd, while the one without prefix is only honored on the host\&.
.sp
Added in version 215\&.
.RE
.PP
\fIsystemd\&.wants=\fR, \fIrd\&.systemd\&.wants=\fR
.RS 4
These options take a unit name as argument\&. A start job for this unit is added to the initial transaction\&. This is useful to start one or more additional units at boot\&. May be specified more than once\&. The option prefixed with
"rd\&."
is honored only in the initrd, while the one that is not prefixed only on the host\&.
.sp
Added in version 215\&.
.RE
.PP
\fIsystemd\&.debug_shell\fR, \fIrd\&.systemd\&.debug_shell\fR, \fIsystemd\&.default_debug_tty=\fR, \fIrd\&.systemd\&.default_debug_tty=\fR
.RS 4
If the
\fBsystemd\&.debug_shell\fR
or
\fBrd\&.systemd\&.debug_shell\fR
option is specified, the debug shell service
"debug\-shell\&.service"
is pulled into the boot transaction and a debug shell will be spawned during early boot\&. By default,
/dev/tty9
is used, but a specific tty can also be specified, either with or without the
/dev/
prefix\&. To set the tty to use without enabling the debug shell, the
\fBsystemd\&.default_debug_tty=\fR
option can be used which also takes a tty with or without the
/dev/
prefix\&. Note that the shell may also be turned on persistently by enabling it with
\fBsystemctl\fR(1)\*(Aqs
\fBenable\fR
command\&. The options prefixed with
"rd\&."
are honored only in the initrd, while the ones without prefix are only honored on the host\&.
.sp
Added in version 215\&.
.RE
.PP
\fIsystemd\&.break=\fR, \fIrd\&.systemd\&.break=\fR
.RS 4
Takes one of
\fBpre\-udev\fR,
\fBpre\-basic\fR,
\fBpre\-mount\fR, or
\fBpre\-switch\-root\fR
(the default for the
"rd\&."
option)\&. It also accepts multiple values separated by comma (",")\&. These options allow one to pause the boot process at a certain point and spawn a debug shell\&. After exiting this shell, the system will resume booting\&. The option prefixed with
"rd\&."
is honored only in the initrd, while the one without prefix is only honored on the host\&.
.sp
.it 1 an-trap
.nr an-no-space-flag 1
.nr an-break-flag 1
.br
.B Table\ \&1.\ \&Available breakpoints
.TS
allbox tab(:);
lB lB lB lB.
T{
Breakpoints
T}:T{
Description
T}:T{
Can be used in the initrd
T}:T{
Can be used on the host
T}
.T&
l l l l
l l l l
l l l l
l l l l.
T{
\fBpre\-udev\fR
T}:T{
Before starting to process kernel uevents, i\&.e\&., before systemd\-udevd\&.service starts\&.
T}:T{
✓
T}:T{
✓
T}
T{
\fBpre\-basic\fR
T}:T{
Before leaving early boot and regular services start, i\&.e\&., before basic\&.target is reached\&.
T}:T{
✓
T}:T{
✓
T}
T{
\fBpre\-mount\fR
T}:T{
Before the root filesystem is mounted, i\&.e\&., before sysroot\&.mount starts\&.
T}:T{
✓
T}:T{
✗
T}
T{
\fBpre\-switch\-root\fR
T}:T{
Before switching from the initrd to the real root\&.
T}:T{
✓
T}:T{
✗
T}
.TE
.sp 1
Added in version 258\&.
.RE
.SH "SYSTEM CREDENTIALS"
.PP
\fIsystemd\&.extra\-unit\&.*\fR
.RS 4
Credentials prefixed with
"systemd\&.extra\-unit\&."
specify additional units to add to the final system\&. Note that these additional units are added to both the initrd and the final system\&.
\fIConditionPathExists=!/etc/initrd\-release\fR
can be used to make sure the unit is conditioned out in the initrd\&. Note that this can also be used to mask units, by simply specifying an empty value\&.
.sp
Added in version 256\&.
.RE
.PP
\fIsystemd\&.unit\-dropin\&.*\fR
.RS 4
Credentials prefixed with
"systemd\&.unit\-dropin\&."
add drop\-ins for the corresponding units in the final system\&. Each credential must be suffixed with the full unit name including the unit extension\&. Its contents must be a valid unit drop\-in file\&. Optionally, the unit name may be followed with
"~", followed by the drop\-in name without the
"\&.conf"
suffix\&. If not specified, the name of the generated drop\-in will be
"50\-credential\&.conf"\&. Note that these additional drop\-ins are added to both the initrd and the final system\&.
.sp
Added in version 256\&.
.RE
.SH "SEE ALSO"
.PP
\fBsystemd\fR(1), \fBsystemctl\fR(1), \fBkernel-command-line\fR(7), \fBsystemd.system-credentials\fR(7), \fBbootup\fR(7)