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diff --git a/chapter07/sysd-custom.xml b/chapter07/sysd-custom.xml new file mode 100644 index 000000000..7f3d4864b --- /dev/null +++ b/chapter07/sysd-custom.xml @@ -0,0 +1,116 @@ +<?xml version="1.0" encoding="ISO-8859-1"?> +<!DOCTYPE sect1 PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" + "http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [ + <!ENTITY % general-entities SYSTEM "../general.ent"> + %general-entities; +]> + +<sect1 id="ch-scripts-sysd-custom"> + <?dbhtml filename="sysd-custom.html"?> + + <title>Systemd Customization</title> + + <indexterm zone="ch-scripts-sysd-custom"> + <primary sortas="e-Systemd">Systemd Customization</primary> + </indexterm> + + <sect2> + <title>Basic Configuration</title> + + <para>The <filename>/etc/systemd/system.conf</filename> file contains a set + of items to control basic operations. The default file has all entries + commented out with the default settings indicated. This file is where the + log level may be changed as well as some basic journal settings.</para> + + </sect2> + + <sect2> + <title>Disabling Screen Clearing at Boot Time</title> + + <para>The normal behavior for systemd is to clear the secreen at + the end of the boot sequence. If desired, this behavior may be + changed by the following:</para> + +<screen role="nodump"><userinput>mkdir -p /etc/systemd/system/getty@tty1.service.d + +cat > /etc/systemd/system/getty@tty1.service.d/noclear.conf << EOF +[Service] +TTYVTDisallocate=no +EOF</userinput></screen> + + <para>The boot messages can always be revied by using the + <userinput>journalctl -b</userinput> command as the root user.</para> + + </sect2> + + <sect2> + <title>Disabling tmpfs for /tmp </title> + + <para>By default, <filename class="directory">/tmp</filename> is created as + a tmpfs. If this is not desired, it can be overridden by the following:</para> + +<screen role="nodump"><userinput>ln -s /dev/null /etc/systemd/system/tmp.mount</userinput></screen> + + <para>This is not necessary if there is a separate partition for /tmp + specified in <filename>/etc/fstab</filename>.</para> + </sect2> + + <sect2> + <title>Configuring Automatic File Creation and Deletion</title> + + <para>There are several services that create or delete files or + directories:</para> + + <itemizedlist> + <listitem><para>systemd-tmpfiles-clean.service</para></listitem> + <listitem><para>systemd-tmpfiles-setup-dev.service</para></listitem> + <listitem><para>systemd-tmpfiles-setup.service</para></listitem> + </itemizedlist> + + <para>The system location for the configuration files is + <filename>/usr/lib/tmpfiles.d/*.conf</filename>. The local + configuration files are in <filename>/etc/tmpfiles.d/*.conf</filename>. + Files in /etc/tmpfiles.d override files with the same name in + /usr/lib/tmpfiles.d. See <userinput>man tmpfiles.d</userinput> + for file format details.</para> + + </sect2> + + <sect2> + <title>Adding Custom Units and Services</title> + + <para>A custom service can be added by creating a directory and + configuration file in <filename class="directory">/etc/systemd/system/</filename>. + For example:</para> + +<screen role="nodump"><userinput>mkdir -p /etc/systemd/system/foobar.service.d + +cat > /etc/systemd/system/foobar.service.d/foobar.conf << EOF +[Service] +Restart=always +RestartSec=30 +EOF</userinput></screen> + + <para>See the man page for systemd.unit for more information. After + creating the configuration file, run <userinput>systemctl + daemon-reload</userinput> and <userinput>systemctl restart + foobar</userinput> to activate a service or changes to a service.</para> + + </sect2> + + <sect2> + <title>Debugging the Boot Sequence</title> + + <para>There are several commands that can be used to help debug the systemd + boot process. Here are some examples:</para> + + <itemizedlist> + <listitem><para>systemctl list-units -t service [--all]</para></listitem> + <listitem><para>systemctl list-units -t target [--all]</para></listitem> + <listitem><para>systemctl show -p Wants multi-user.target</para></listitem> + <listitem><para>systemctl status sshd.service</para></listitem> + </itemizedlist> + + </sect2> + +</sect1> |