From fdb010e56b19cd0efb7866fb3d0cc16b008ea3a7 Mon Sep 17 00:00:00 2001
From: Sam Yaple <sam@yaple.net>
Date: Thu, 5 Nov 2015 09:10:47 +0000
Subject: [PATCH] Add additional ntp information around ceph
Mention `chrony` since thats what docs.openstack.org recommends for
WAN connections. It does do better than ntpd
Change-Id: I28caade26492294bf12b092ff949003c7bf0bb8e
---
doc/quickstart.rst | 25 ++++++++++++++++---------
1 file changed, 16 insertions(+), 9 deletions(-)
diff --git a/doc/quickstart.rst b/doc/quickstart.rst
index 0eedcc569..1eac54c59 100644
--- a/doc/quickstart.rst
+++ b/doc/quickstart.rst
@@ -126,13 +126,17 @@ To install these clients use:
pip install -U python-openstackclient
-OpenStack uses healthcheck timers which run off wall-clock time rather then
-starting a timer and expiring the timer, encoding the expiration in the message
-contents. In some cases, this timer interval can be on the order of 60
-seconds. For OpenStack to operate correctly with these tight health-check
-timer intervals, the Kolla community highly recommends running the ntpd
-service on all deployment targets. To install, start, and enable ntp
-execute the following:
+OpenStack, RabbitMQ, and Ceph require all hosts to have matching times to ensure
+proper message delivery. In the case of Ceph, it will complain if the hosts
+differ by more than 0.05 seconds. Some OpenStack services have timers as low as
+2 seconds by default. For these reasons it is highly recommended to setup an NTP
+service of some kind. While `ntpd` will achieve more accurate time for the
+deployment if the NTP servers are running in the local deployment environment,
+`chrony <http://chrony.tuxfamily.org>`_ is more accurate when syncing the time
+across a WAN connection. When running Ceph it is recommended to setup `ntpd` to
+sync time locally due to the tight time constraints.
+
+To install, start, and enable ntp on CentOS execute the following:
::
@@ -141,8 +145,11 @@ execute the following:
systemctl enable ntpd
systemctl start ntpd
- # Ubuntu
- sudo apt-get install ntp
+To install and start on Debian based systems execute the following:
+
+::
+
+ apt-get install ntp
Libvirt is started by default on many operating systems. Please disable libvirt
on any machines that will be deployment targets. Only one copy of libvirt may
--
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