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Configure time synchronization with an external NTP server on the server

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In OS images for installation on dedicated servers provided by Selectel, all necessary settings for NTP are already configured. You need to configure NTP in the server OS if you install the OS manually from your own image.

  1. Check the installed utility.
  2. Configure the utility.

1. Check the installed utility

  1. Connect to the server via SSH or via KVM console.

  2. Check which utility is used on the server:

    systemctl status ntp
    systemctl status chronyd
    systemctl status systemd-timesyncd

    We recommend using Chrony, but you can configure the utility that is already installed on the server.

  3. If you want to switch to Chrony:

    3.1. Disable and remove the systemd-timesyncd and ntpd utilities:

    systemctl disable <name>
    sudo apt remove <name>

    Specify <name> — the name of the utility to remove: ntp or systemd-timesyncd.

    3.2. Install Chrony:

    sudo apt-get install chronyd

2. Configure the utility

  1. Start Chrony:

    systemctl start chronyd

  2. Open the Chrony configuration file in the vi text editor:

    vi /etc/chrony/chrony.conf

  3. Add or replace NTP servers in the file. We recommend replacing the servers in the file with Selectel NTP servers, but you can specify any available NTP servers.

    server <domain> iburst

    Specify <domain> — the domain name or the address of the pool or server.

    If you need to specify multiple servers, provide each on a new line, for example:

    server 0.spb.ntp.selectel.ru iburst
    server 1.spb.ntp.selectel.ru iburst

  4. Exit the vi text editor with your changes saved:

    :wq

  5. Restart the Chrony utility:

    sudo systemctl restart chronyd

  6. Check the list of NTP servers used:

    chronyc -N sources