man/systemd-debug-generator.xml

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   5   SPDX-License-Identifier: LGPL-2.1+
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   7 <refentry id="systemd-debug-generator">
   8
   9   <refentryinfo>
  10     <title>systemd-debug-generator</title>
  11     <productname>systemd</productname>
  12   </refentryinfo>
  13
  14   <refmeta>
  15     <refentrytitle>systemd-debug-generator</refentrytitle>
  16     <manvolnum>8</manvolnum>
  17   </refmeta>
  18
  19   <refnamediv>
  20     <refname>systemd-debug-generator</refname>
  21     <refpurpose>Generator for enabling a runtime debug shell and
  22     masking specific units at boot</refpurpose>
  23   </refnamediv>
  24
  25   <refsynopsisdiv>
  26     <para><filename>/usr/lib/systemd/system-generators/systemd-debug-generator</filename></para>
  27   </refsynopsisdiv>
  28
  29   <refsect1>
  30     <title>Description</title>
  31
  32     <para><filename>systemd-debug-generator</filename> is a generator
  33     that reads the kernel command line and understands three
  34     options:</para>
  35
  36     <para>If the <option>systemd.mask=</option> or <option>rd.systemd.mask=</option>
  37     option is specified and followed by a unit name, this unit is
  38     masked for the runtime, similar to the effect of
  39     <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  40     <command>mask</command> command. This is useful to boot with
  41     certain units removed from the initial boot transaction for
  42     debugging system startup. May be specified more than once.
  43     <option>rd.systemd.mask=</option> is honored only by initial
  44     RAM disk (initrd) while <option>systemd.mask=</option> is
  45     honored only in the main system.</para>
  46
  47     <para>If the <option>systemd.wants=</option> or
  48     <option>rd.systemd.wants=</option> option is specified
  49     and followed by a unit name, a start job for this unit is added to
  50     the initial transaction. This is useful to start one or more
  51     additional units at boot. May be specified more than once.
  52     <option>rd.systemd.wants=</option> is honored only by initial
  53     RAM disk (initrd) while <option>systemd.wants=</option> is
  54     honored only in the main system.</para>
  55
  56     <para>If the <option>systemd.debug_shell</option> or
  57     <option>rd.systemd.debug_shell</option> option is
  58     specified, the debug shell service
  59     <literal>debug-shell.service</literal> is pulled into the boot
  60     transaction. It will spawn a debug shell on tty9 during early
  61     system startup. Note that the shell may also be turned on
  62     persistently by enabling it with
  63     <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
  64     <command>enable</command> command.
  65     <option>rd.systemd.debug_shell=</option> is honored only by initial
  66     RAM disk (initrd) while <option>systemd.debug_shell</option> is
  67     honored only in the main system.</para>
  68
  69     <para><filename>systemd-debug-generator</filename> implements
  70     <citerefentry><refentrytitle>systemd.generator</refentrytitle><manvolnum>7</manvolnum></citerefentry>.</para>
  71   </refsect1>
  72
  73   <refsect1>
  74     <title>See Also</title>
  75     <para>
  76       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  77       <citerefentry><refentrytitle>systemctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
  78       <citerefentry><refentrytitle>kernel-command-line</refentrytitle><manvolnum>7</manvolnum></citerefentry>
  79     </para>
  80   </refsect1>
  81
  82 </refentry>