Added systemd and dbus to the book.

Set up systemd and System V side-by-side with the
ability to reboot to either system.


git-svn-id: http://svn.linuxfromscratch.org/LFS/trunk/BOOK@10520 4aa44e1e-78dd-0310-a6d2-fbcd4c07a689

1 files changed, 106 insertions, 42 deletions

diff --git a/chapter07/setclock.xml b/chapter07/setclock.xml
index 1daa445ef..729c447f6 100644
--- a/chapter07/setclock.xml
+++ b/chapter07/setclock.xml
@@ -5,46 +5,53 @@
   %general-entities;
 ]>
 
-<sect1 id="ch-scripts-setclock">
-  <?dbhtml filename="setclock.html"?>
+<sect1 id="ch-scripts-clock">
+  <?dbhtml filename="clock.html"?>
 
-  <title>Configuring the setclock Script</title>
+  <title>Configuring the System Clock</title>
 
-  <indexterm zone="ch-scripts-setclock">
-    <primary sortas="d-setclock">setclock</primary>
-  <secondary>configuring</secondary></indexterm>
+  <para>Procedures for setting the system clock differ between systemd and 
+  System V, however the separate procedures do not conflict so both
+  procedures should be accomplished to allow switching between systems.</para>
+
+  <sect2 id="ch-scripts-setclock">
+    <title>System V Clock Configuration</title>
+
+    <indexterm zone="ch-scripts-setclock">
+      <primary sortas="d-setclock">setclock</primary>
+    <secondary>configuring</secondary></indexterm>
+
+    <para>The <command>setclock</command> script reads the time from the hardware
+    clock, also known as the BIOS or the Complementary Metal Oxide Semiconductor
+    (CMOS) clock. If the hardware clock is set to UTC, this script will convert the
+    hardware clock's time to the local time using the
+    <filename>/etc/localtime</filename> file (which tells the
+    <command>hwclock</command> program which timezone the user is in). There is no
+    way to detect whether or not the hardware clock is set to UTC, so this
+    needs to be configured manually.</para>
+
+    <para>The <command>setclock</command> is run via
+    <application>udev</application> when the kernel detects the hardware
+    capability upon boot.  It can also be run manually with the stop parameter to
+    store the system time to the CMOS clock.</para>
+
+    <para>If you cannot remember whether or not the hardware clock is set to UTC,
+    find out by running the <userinput>hwclock --localtime --show</userinput>
+    command. This will display what the current time is according to the hardware
+    clock. If this time matches whatever your watch says, then the hardware clock is
+    set to local time. If the output from <command>hwclock</command> is not local
+    time, chances are it is set to UTC time. Verify this by adding or subtracting
+    the proper amount of hours for the timezone to the time shown by
+    <command>hwclock</command>. For example, if you are currently in the MST
+    timezone, which is also known as GMT -0700, add seven hours to the local
+    time.</para>
+
+    <para>Change the value of the <envar>UTC</envar> variable below
+    to a value of <parameter>0</parameter> (zero) if the hardware clock
+    is <emphasis>not</emphasis> set to UTC time.</para>
 
-  <para>The <command>setclock</command> script reads the time from the hardware
-  clock, also known as the BIOS or the Complementary Metal Oxide Semiconductor
-  (CMOS) clock. If the hardware clock is set to UTC, this script will convert the
-  hardware clock's time to the local time using the
-  <filename>/etc/localtime</filename> file (which tells the
-  <command>hwclock</command> program which timezone the user is in). There is no
-  way to detect whether or not the hardware clock is set to UTC, so this
-  needs to be configured manually.</para>
-
-  <para>The <command>setclock</command> is run via
-  <application>udev</application> when the kernel detects the hardware
-  capability upon boot.  It can also be run manually with the stop parameter to
-  store the system time to the CMOS clock.</para>
-
-  <para>If you cannot remember whether or not the hardware clock is set to UTC,
-  find out by running the <userinput>hwclock --localtime --show</userinput>
-  command. This will display what the current time is according to the hardware
-  clock. If this time matches whatever your watch says, then the hardware clock is
-  set to local time. If the output from <command>hwclock</command> is not local
-  time, chances are it is set to UTC time. Verify this by adding or subtracting
-  the proper amount of hours for the timezone to the time shown by
-  <command>hwclock</command>. For example, if you are currently in the MST
-  timezone, which is also known as GMT -0700, add seven hours to the local
-  time.</para>
-
-  <para>Change the value of the <envar>UTC</envar> variable below
-  to a value of <parameter>0</parameter> (zero) if the hardware clock
-  is <emphasis>not</emphasis> set to UTC time.</para>
-
-  <para>Create a new file <filename>/etc/sysconfig/clock</filename> by running
-  the following:</para>
+    <para>Create a new file <filename>/etc/sysconfig/clock</filename> by running
+    the following:</para>
 
 <screen><userinput>cat &gt; /etc/sysconfig/clock &lt;&lt; "EOF"
 <literal># Begin /etc/sysconfig/clock
@@ -58,11 +65,68 @@ CLOCKPARAMS=
 # End /etc/sysconfig/clock</literal>
 EOF</userinput></screen>
 
-  <para>A good hint explaining how to deal with time on LFS is available
-  at <ulink url="&hints-root;time.txt"/>. It explains issues such as
-  time zones, UTC, and the <envar>TZ</envar> environment variable.</para>
+    <para>A good hint explaining how to deal with time on LFS is available
+    at <ulink url="&hints-root;time.txt"/>. It explains issues such as
+    time zones, UTC, and the <envar>TZ</envar> environment variable.</para>
+
+    <note><para>The CLOCKPARAMS and UTC paramaters may be alternatively set
+    in the <filename>/etc/sysconfig/rc.site</filename> file.</para></note>
+
+  </sect2>
+
+  <sect2 id="ch-scripts-systemd-clock">
+    <title>Systemd Clock Configuration</title>
+
+  <indexterm zone="ch-scripts-clock">
+    <primary sortas="d-clock">clock</primary>
+  <secondary>configuring</secondary></indexterm>
+
+  <para>This section discusses how to configure the
+  <command>systemd-timedated</command> system service, which configures
+  system clock and timezone.</para>
+
+  <para><command>systemd-timedated</command> reads
+  <filename>/etc/adjtime</filename>, and depending on the contents of the file,
+  it sets the clock to either UTC or local time.  Create the
+  <filename>/etc/adjtime</filename> file with the following contents <emphasis>if your
+  hardware clock is set to local time</emphasis>:</para>
+
+<screen role="nodump"><userinput>cat &gt; /etc/adjtime &lt;&lt; "EOF"
+<literal>0.0 0 0.0
+0
+LOCAL</literal>
+EOF</userinput></screen>
+
+    <para>If <filename>/etc/adjtime</filename> isn't present at first boot,
+    <command>systemd-timedated</command> will assume that hardware clock is
+    set to UTC and create the file using that setting.</para>
+
+    <para>You can also use the <command>timedatectl</command> utility to tell
+    <command>systemd-timedated</command> if your hardware clock is set to
+    UTC or local time:</para>
+
+<screen role="nodump"><userinput>timedatectl set-local-rtc 1</userinput></screen>
+
+    <para><command>timedatectl</command> can also be used to change system time and
+    time zone.</para>
+
+    <para>To change your current system time, issue:</para>
+
+<screen role="nodump"><userinput>timedatectl set-time YYYY:MM:DD HH:MM:SS</userinput></screen>
+
+    <para>Hardware clock will also be updated accordingly.</para>
+
+    <para>To change your current time zone, issue:</para>
+
+<screen role="nodump"><userinput>timedatectl set-timezone TIMEZONE</userinput></screen>
+
+    <para>You can get list of available time zones by running:</para>
+
+<screen role="nodump"><userinput>timedatectl list-timezones</userinput></screen>
+
+    <note><para>Please note that <command>timedatectl</command> command can
+    be used only on a system booted with Systemd.</para></note>
 
-  <note><para>The CLOCKPARAMS and UTC paramaters may be alternatively set
-  in the <filename>/etc/sysconfig/rc.site</filename> file.</para></note>
+  </sect2>
 
 </sect1>