openstack-manuals/doc/install-guide-rst/source/basics-ntp.rst

Network Time Protocol (NTP)

You must install Network Time Protocol (NTP) 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.

Controller node

To install the NTP service

ubuntu or debian

# apt-get install ntp

rdo

# yum install ntp

obs

# zypper install ntp

To configure the NTP service

By default, the controller node synchronizes the time via a pool of public servers. However, you can optionally edit the /etc/ntp.conf file to configure alternative servers such as those provided by your organization.

1. Edit the /etc/ntp.conf file and add, change, or remove the following keys as necessary for your environment:

   server NTP_SERVER iburst
   restrict -4 default kod notrap nomodify
   restrict -6 default kod notrap nomodify

   Replace NTP_SERVER with the hostname or IP address of a suitable more accurate (lower stratum) NTP server. The configuration supports multiple server keys.

   Note

   For the restrict keys, you essentially remove the nopeer and noquery options.

   ubuntu or debian

   Note

   Remove the /var/lib/ntp/ntp.conf.dhcp file if it exists.

ubuntu or debian

2. Restart the NTP service:

   # service ntp restart

rdo or obs

2. Start the NTP service and configure it to start when the system boots:

   # systemctl enable ntpd.service
   # systemctl start ntpd.service

Other nodes

To install the NTP service

ubuntu or debian

# apt-get install ntp

rdo

# yum install ntp

obs

# zypper install ntp

To configure the NTP service

Configure the network and compute nodes to reference the controller node.

1. Edit the /etc/ntp.conf file:

   Comment out or remove all but one server key and change it to reference the controller node.

   server controller iburst

   ubuntu or debian

   Note

   Remove the /var/lib/ntp/ntp.conf.dhcp file if it exists.

ubuntu or debian

2. Restart the NTP service:

   # service ntp restart

rdo or obs

2. Start the NTP service and configure it to start when the system boots:

   # systemctl enable ntpd.service
   # systemctl start ntpd.service

Verify operation

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.

1. Run this command on the controller node:

   # ntpq -c peers
     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

   Contents in the remote column should indicate the hostname or IP address of one or more NTP servers.

   Note

   Contents in the refid column typically reference IP addresses of upstream servers.

2. Run this command on the controller node:

   # ntpq -c assoc
   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

   Contents in the condition column should indicate sys.peer for at least one server.

3. Run this command on all other nodes:

   # ntpq -c peers
   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

   Contents in the remote column should indicate the hostname of the controller node.

   Note

   Contents in the refid column typically reference IP addresses of upstream servers.

4. Run this command on all other nodes:

   # ntpq -c assoc
   ind assid status  conf reach auth condition  last_event cnt
   ===========================================================
   1   21181  963a   yes   yes  none  sys.peer    sys_peer  3

   Contents in the condition column should indicate sys.peer.