openstack/openstack-manuals
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openstack-manuals/doc/install-guide/section_basics-ntp.xml
Andreas Jaeger 626b92bea2 Install Guide: Basic Chapter fixes openSUSE/SLES 
Since SLES 12 and openSUSE 13.2 both use systemd, we can remove special
handling for them and also merge instructions with the Fedora based
distros.

Update specifice instructions in Basic chapter.

Change-Id: I16bc5695e60dd00e54c4eb63caf4ccf08bc36842
2015-04-13 13:50:13 +02:00

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<?xml version="1.0" encoding="UTF-8"?>
<section xmlns="http://docbook.org/ns/docbook"
xmlns:xi="http://www.w3.org/2001/XInclude"
xmlns:xlink="http://www.w3.org/1999/xlink"
version="5.0"
xml:id="basics-ntp">
<?dbhtml stop-chunking?>
<title>Network Time Protocol (NTP)</title>
<para>You must install
<glossterm baseform="Network Time Protocol (NTP)">NTP</glossterm> to
properly synchronize services among nodes. We recommend that you configure
the controller node to reference more accurate (lower stratum) servers and
other nodes to reference the controller node.</para>
<section xml:id="basics-ntp-controller-node">
<title>Controller node</title>
<procedure>
<title>To install the NTP service</title>
<step>
<screen os="ubuntu;debian"><prompt>#</prompt> <userinput>apt-get install ntp</userinput></screen>
<screen os="rhel;fedora;centos"><prompt>#</prompt> <userinput>yum install ntp</userinput></screen>
<screen os="opensuse;sles"><prompt>#</prompt> <userinput>zypper install ntp</userinput></screen>
</step>
</procedure>
<procedure>
<title>To configure the NTP service</title>
<para>By default, the controller node synchronizes the time via a pool
of public servers. However, you can optionally edit the
<filename>/etc/ntp.conf</filename> file to configure alternative
servers such as those provided by your organization.</para>
<step>
<para>Edit the <filename>/etc/ntp.conf</filename> file and add,
change, or remove the following keys as necessary for your
environment:</para>
<programlisting language="ini">server <replaceable>NTP_SERVER</replaceable> iburst
restrict -4 default kod notrap nomodify
restrict -6 default kod notrap nomodify</programlisting>
<para>Replace <replaceable>NTP_SERVER</replaceable> with the
hostname or IP address of a suitable more accurate (lower stratum)
NTP server. The configuration supports multiple
<literal>server</literal> keys.</para>
<note>
<para>For the <literal>restrict</literal> keys, you essentially
remove the <literal>nopeer</literal> and <literal>noquery</literal>
options.</para>
</note>
<note os="ubuntu;debian">
<para>Remove the <filename>/var/lib/ntp/ntp.conf.dhcp</filename> file
if it exists.</para>
</note>
</step>
<step os="ubuntu;debian">
<para>Restart the NTP service:</para>
<screen><prompt>#</prompt> <userinput>service ntp restart</userinput></screen>
</step>
<step os="rhel;centos;fedora;sles;opensuse">
<para>Start the NTP service and configure it to start when the system
boots:</para>
<screen><prompt>#</prompt> <userinput>systemctl enable ntpd.service</userinput>
<prompt>#</prompt> <userinput>systemctl start ntpd.service</userinput></screen>
</step>
</procedure>
</section>
<section xml:id="basics-ntp-other-nodes">
<title>Other nodes</title>
<procedure>
<title>To install the NTP service</title>
<step>
<screen os="ubuntu;debian"><prompt>#</prompt> <userinput>apt-get install ntp</userinput></screen>
<screen os="rhel;fedora;centos"><prompt>#</prompt> <userinput>yum install ntp</userinput></screen>
<screen os="opensuse;sles"><prompt>#</prompt> <userinput>zypper install ntp</userinput></screen>
</step>
</procedure>
<procedure>
<title>To configure the NTP service</title>
<para>Configure the network and compute nodes to reference the
controller node.</para>
<step>
<para>Edit the <filename>/etc/ntp.conf</filename> file:</para>
<para>Comment out or remove all but one <literal>server</literal>
key and change it to reference the controller node.</para>
<programlisting language="ini">server <replaceable>controller</replaceable> iburst</programlisting>
<note os="ubuntu;debian">
<para>Remove the <filename>/var/lib/ntp/ntp.conf.dhcp</filename> file
if it exists.</para>
</note>
</step>
<step os="ubuntu;debian">
<para>Restart the NTP service:</para>
<screen><prompt>#</prompt> <userinput>service ntp restart</userinput></screen>
</step>
<step os="rhel;centos;fedora;sles;opensuse">
<para>Start the NTP service and configure it to start when the system
boots:</para>
<screen><prompt>#</prompt> <userinput>systemctl enable ntpd.service</userinput>
<prompt>#</prompt> <userinput>systemctl start ntpd.service</userinput></screen>
</step>
</procedure>
</section>
<section xml:id="basics-ntp-verify">
<title>Verify operation</title>
<para>We recommend that you verify NTP synchronization before proceeding
further. Some nodes, particularly those that reference the controller
node, can take several minutes to synchronize.</para>
<procedure>
<step>
<para>Run this command on the <emphasis>controller</emphasis> node:
</para>
<screen><prompt>#</prompt> <userinput>ntpq -c peers</userinput>
<computeroutput> remote refid st t when poll reach delay offset jitter
==============================================================================
*ntp-server1 192.0.2.11 2 u 169 1024 377 1.901 -0.611 5.483
+ntp-server2 192.0.2.12 2 u 887 1024 377 0.922 -0.246 2.864</computeroutput></screen>
<para>Contents in the <emphasis>remote</emphasis> column should
indicate the hostname or IP address of one or more NTP servers.</para>
<note>
<para>Contents in the <emphasis>refid</emphasis> column typically
reference IP addresses of upstream servers.</para>
</note>
</step>
<step>
<para>Run this command on the <emphasis>controller</emphasis> node:
</para>
<screen><prompt>#</prompt> <userinput>ntpq -c assoc</userinput>
<computeroutput>ind assid status conf reach auth condition last_event cnt
===========================================================
1 20487 961a yes yes none sys.peer sys_peer 1
2 20488 941a yes yes none candidate sys_peer 1</computeroutput></screen>
<para>Contents in the <emphasis>condition</emphasis> column should
indicate <literal>sys.peer</literal> for at least one server.</para>
</step>
<step>
<para>Run this command on <emphasis>all other</emphasis> nodes:</para>
<screen><prompt>#</prompt> <userinput>ntpq -c peers</userinput>
<computeroutput> remote refid st t when poll reach delay offset jitter
==============================================================================
*controller 192.0.2.21 3 u 47 64 37 0.308 -0.251 0.079</computeroutput></screen>
<para>Contents in the <emphasis>remote</emphasis> column should
indicate the hostname of the controller node.</para>
<note>
<para>Contents in the <emphasis>refid</emphasis> column typically
reference IP addresses of upstream servers.</para>
</note>
</step>
<step>
<para>Run this command on <emphasis>all other</emphasis> nodes:
</para>
<screen><prompt>#</prompt> <userinput>ntpq -c assoc</userinput>
<computeroutput>ind assid status conf reach auth condition last_event cnt
===========================================================
1 21181 963a yes yes none sys.peer sys_peer 3</computeroutput></screen>
<para>Contents in the <emphasis>condition</emphasis> column should
indicate <literal>sys.peer</literal>.</para>
</step>
</procedure>
</section>
</section>
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