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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-systemd-custom">
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+ <?dbhtml filename="systemd-custom.html"?>
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+
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+ <title>Systemd Usage and Configuration</title>
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+
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+ <indexterm zone="ch-scripts-systemd-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 options to control basic systemd operations. The default file has all
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+ entries commented out with the default settings indicated. This file is
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+ where the log level may be changed as well as some basic logging settings.
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+ See <filename>systemd-system.conf(5)</filename> manual page for details on
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+ each configuration option.</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 running the following command:</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 -sfv /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
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+ <filename class="directory">/tmp</filename> specified in
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+ <filename>/etc/fstab</filename>.</para>
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+
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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
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+ <filename class="directory">/etc/tmpfiles.d</filename>. Files in
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+ <filename class="directory">/etc/tmpfiles.d</filename> override
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+ files with the same name in
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+ <filename class="directory">/usr/lib/tmpfiles.d</filename>. See
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+ <filename>tmpfiles.d(5)</filename> manual page for file format
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+ 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>Overriding Default Services Behavior</title>
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+
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+ <para>A systemd service contents can be overriden by creating a directory
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+ and a configuration file in <filename
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+ class="directory">/etc/systemd/system</filename>. 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 <filename>systemd.unit(5)</filename> manual page for more
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+ information. After creating the configuration file, run
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+ <userinput>systemctl daemon-reload</userinput> and <userinput>systemctl
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+ restart foobar</userinput> to activate the 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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Krejzi