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+<?xml version="1.0" encoding="ISO-8859-1"?>
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+<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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+ "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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+ <!ENTITY % general-entities SYSTEM "../general.ent">
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+ %general-entities;
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+]>
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+
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+<sect1 id="ch-scripts-sysd-custom">
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+ <?dbhtml filename="sysd-custom.html"?>
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+
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+ <title>Systemd Customization</title>
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+
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+ <indexterm zone="ch-scripts-sysd-custom">
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+ <primary sortas="e-Systemd">Systemd Customization</primary>
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+ </indexterm>
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+
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+ <sect2>
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+ <title>Basic Configuration</title>
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+
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+ <para>The <filename>/etc/systemd/system.conf</filename> file contains a set
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+ of items to control basic operations. The default file has all entries
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+ commented out with the default settings indicated. This file is where the
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+ log level may be changed as well as some basic journal settings.</para>
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+
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+ </sect2>
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+
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+ <sect2>
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+ <title>Disabling Screen Clearing at Boot Time</title>
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+
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+ <para>The normal behavior for systemd is to clear the secreen at
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+ the end of the boot sequence. If desired, this behavior may be
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+ changed by the following:</para>
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+
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+<screen role="nodump"><userinput>mkdir -p /etc/systemd/system/getty@tty1.service.d
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+
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+cat > /etc/systemd/system/getty@tty1.service.d/noclear.conf << EOF
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+[Service]
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+TTYVTDisallocate=no
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+EOF</userinput></screen>
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+
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+ <para>The boot messages can always be revied by using the
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+ <userinput>journalctl -b</userinput> command as the root user.</para>
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+
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+ </sect2>
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+
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+ <sect2>
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+ <title>Disabling tmpfs for /tmp </title>
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+
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+ <para>By default, <filename class="directory">/tmp</filename> is created as
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+ a tmpfs. If this is not desired, it can be overridden by the following:</para>
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+
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+<screen role="nodump"><userinput>ln -s /dev/null /etc/systemd/system/tmp.mount</userinput></screen>
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+
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+ <para>This is not necessary if there is a separate partition for /tmp
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+ specified in <filename>/etc/fstab</filename>.</para>
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+ </sect2>
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+
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+ <sect2>
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+ <title>Configuring Automatic File Creation and Deletion</title>
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+
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+ <para>There are several services that create or delete files or
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+ directories:</para>
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+
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+ <itemizedlist>
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+ <listitem><para>systemd-tmpfiles-clean.service</para></listitem>
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+ <listitem><para>systemd-tmpfiles-setup-dev.service</para></listitem>
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+ <listitem><para>systemd-tmpfiles-setup.service</para></listitem>
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+ </itemizedlist>
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+
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+ <para>The system location for the configuration files is
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+ <filename>/usr/lib/tmpfiles.d/*.conf</filename>. The local
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+ configuration files are in <filename>/etc/tmpfiles.d/*.conf</filename>.
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+ Files in /etc/tmpfiles.d override files with the same name in
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+ /usr/lib/tmpfiles.d. See <userinput>man tmpfiles.d</userinput>
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+ for file format details.</para>
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+
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+ </sect2>
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+
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+ <sect2>
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+ <title>Adding Custom Units and Services</title>
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+
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+ <para>A custom service can be added by creating a directory and
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+ configuration file in <filename class="directory">/etc/systemd/system/</filename>.
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+ For example:</para>
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+
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+<screen role="nodump"><userinput>mkdir -p /etc/systemd/system/foobar.service.d
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+
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+cat > /etc/systemd/system/foobar.service.d/foobar.conf << EOF
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+[Service]
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+Restart=always
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+RestartSec=30
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+EOF</userinput></screen>
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+
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+ <para>See the man page for systemd.unit for more information. After
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+ creating the configuration file, run <userinput>systemctl
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+ daemon-reload</userinput> and <userinput>systemctl restart
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+ foobar</userinput> to activate a service or changes to a service.</para>
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+
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+ </sect2>
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+
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+ <sect2>
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+ <title>Debugging the Boot Sequence</title>
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+
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+ <para>There are several commands that can be used to help debug the systemd
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+ boot process. Here are some examples:</para>
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+
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+ <itemizedlist>
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+ <listitem><para>systemctl list-units -t service [--all]</para></listitem>
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+ <listitem><para>systemctl list-units -t target [--all]</para></listitem>
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+ <listitem><para>systemctl show -p Wants multi-user.target</para></listitem>
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+ <listitem><para>systemctl status sshd.service</para></listitem>
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+ </itemizedlist>
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+
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+ </sect2>
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+
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+</sect1>
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Bruce Dubbs