Paulgear Ntp

  • By Paul Gear
Channel Version Revision Published Runs on
latest/stable 65 65 19 Mar 2021
Ubuntu 18.04 Ubuntu 17.10 Ubuntu 16.04 Ubuntu 14.04
latest/candidate 105 105 09 Feb 2022
Ubuntu 18.10 Ubuntu 18.04 Ubuntu 17.10 Ubuntu 16.04 Ubuntu 14.04
juju deploy paulgear-ntp
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18.04 17.10 16.04 14.04


NTP provides network based time services to ensure synchronization of time across computers.


The ntp charm is a subordinate charm which is designed for use with other principal charms. It can be used in two ways:


In this mode, the ntp charm is used to configure NTP in other service units to talk directly to a set of NTP time sources:

juju deploy ntp
juju add-relation ntp myservice

By default this charm uses the standard set of NTP pool servers which are configured in the ntp Ubuntu package.

However, if you have a handy atomic clock on your network which you would prefer to use then you can add that:

juju set ntp

You can also specify multiple sources and peers:

juju set ntp source=""
juju set ntp peers=""

To disable the default list of pool servers, set that to the empty string:

juju set ntp pools=""

Sources, peers, and pools should be space separated.

If you have a large number of nodes which need to keep close sync with one another but need to keep upstream traffic to a minimum, try auto_peers:

juju set ntp auto_peers=true

This will select the most suitable units for connecting with upstream, and configure the remaining units to receive time from those units.


In the event that you don't wish every server on your network to talk directly to your configured time sources, you can use this charm in-conjunction with the ntpmaster charm:

juju deploy ntp
juju deploy ntpmaster
juju add-relation ntp ntpmaster

This allows you to gate NTP services to a single set of servers within your control.

This might have application in more secure network environments where general outbound network access to the Internet is not avaliable or desirable and you don't have a good internal time source such as an atomic clock.

You can of course have more than one ntpmaster:

juju add-unit ntpmaster

All services that the ntp charm is subordinate to will be configured to sync with all avaliable masters.

The ntpmaster charm supports the same "source" configuration that the ntp charm does.

The ntp charm can also be used in place of the ntpmaster charm when coupled with another primary charm:

juju deploy ntp ntp-masters
juju deploy ubuntu --num-units=4
juju add-relation ubuntu ntp-masters
juju set ntp-masters auto_peers=true

juju deploy ntp
juju deploy my-other-service --num-units=30
juju add-relation ntp my-other-service
juju add-relation ntp ntp-masters

This is the recommended method, since this charm provides better monitoring and more flexible configuration than ntpmaster.