NTP Client/Server (chrony) Configuration

AstLinux now supports the chrony package, a versatile implementation of the Network Time Protocol NTP. It can synchronize the system clock with NTP servers, and can also operate as an NTPv4 (RFC 5905) server and peer to provide a time service to other computers in the network.

Note: AstLinux 1.2.9 or later is required for 'chrony' specific features

Select the Network Tab in the web interface.
Network Tab

Locate the “NTP Server” entry within Network Time Settings:

Enter user defined NTP Servers (space separated) or select a regional “pool” server, “Save Settings”, then “Restart NTP Time” to apply.

Tip -> Any changes to the “Timezone” selection within this entry requires a System Reboot to apply.

Nothing additional to configure, any local LAN interface device can use the LAN gateway address as an NTP server (UDP 123).

Tip -> By default, the DHCP “ntp-server” options field provides the NTP server for each DHCP configured network segment.

By default a /etc/chrony.conf file is automatically generated from web interface settings. For most users this is sufficient, and recommended, providing automatic /etc/chrony.conf configuration tweaks over time.

For advanced users who want addition control of the /etc/chrony.conf configuration, they can create a persistent /mnt/kd/chrony.conf file that will be automatically sym-linked to /etc/chrony.conf.

Using the CLI, here is a brief how-to on generating a custom configuration for chrony.

Create a persistent /mnt/kd/chrony.conf file from the current automatically generated version:

cp /etc/chrony.conf /mnt/kd/chrony.conf

Now edit /mnt/kd/chrony.conf to your liking, probably delete the “Autogenerated” first line so it won't confuse you later.

Now restart the NTP daemon with the new /mnt/kd/chrony.conf file:

service ntpd stop
service ntpd init

Tip -> The web interface Network and Edit tab will support editing the /mnt/kd/chrony.conf file if it exists.

If you want to specify a persistent driftfile, the destination directory must have ntp:ntp user/group privileges. For example:

mkdir /mnt/kd/ntp
chown ntp:ntp /mnt/kd/ntp

Then in your custom /mnt/kd/chrony.conf file, edit the driftfile line to:

driftfile /mnt/kd/ntp/chrony.drift

Then restart the NTP daemon (as above) to apply the change.

Chrony Documentation

The chronyc command connects to the chronyd daemon to retrieve useful information. If chronyc is entered by itself you will enter an interactive mode with a chronyc> prompt (supports tab-completion of commands). Or just enter chronyc commands on the command line.

Note -> Some chronyc commands can actively change the chronyd operation, so carefully choose what commands you issue. Below are some safe examples.

Display information about current sources: (append -v for verbose)

chronyc sources

Display statistics about collected measurements: (append -v for verbose)

chronyc sourcestats

Display system time information:

chronyc tracking

Report on clients that have accessed the server:

chronyc clients

Display a list of commands:

chronyc help

  • userdoc/tt_ntp_client_server.txt
  • Last modified: 2016/12/09 12:24
  • by abelbeck