Chapter 11. Configuring time synchronization using RHEL System Roles

With the timesync RHEL System Role, you can manage time synchronization on multiple target machines on RHEL using Red Hat Ansible Automation Platform.

11.1. The timesync System Role

You can manage time synchronization on multiple target machines using the timesync RHEL System Role.

The timesync role installs and configures an NTP or PTP implementation to operate as an NTP client or PTP replica in order to synchronize the system clock with NTP servers or grandmasters in PTP domains.

Note that using the timesync role also facilitates the migration to chrony, because you can use the same playbook on all versions of Red Hat Enterprise Linux starting with RHEL 6 regardless of whether the system uses ntp or chrony to implement the NTP protocol.

11.2. Applying the timesync System Role for a single pool of servers

The following example shows how to apply the timesync role in a situation with just one pool of servers.

Warning

The timesync role replaces the configuration of the given or detected provider service on the managed host. Previous settings are lost, even if they are not specified in the role variables. The only preserved setting is the choice of provider if the timesync_ntp_provider variable is not defined.

Prerequisites

  • You have Red Hat Ansible Engine installed on the system from which you want to run the playbook.

    Note

    You do not have to have Red Hat Ansible Automation Platform installed on the systems on which you want to deploy the timesync solution.

  • You have the rhel-system-roles package installed on the system from which you want to run the playbook.
  • You have an inventory file which lists the systems on which you want to deploy timesync System Role.

Procedure

  1. Create a new playbook.yml file with the following content:

    ---
    - hosts: timesync-test
      vars:
        timesync_ntp_servers:
          - hostname: 2.rhel.pool.ntp.org
            pool: yes
            iburst: yes
      roles:
        - rhel-system-roles.timesync
  2. Optional: Verify playbook syntax.

    # ansible-playbook --syntax-check playbook.yml
  3. Run the playbook on your inventory file:

    # ansible-playbook -i inventory_file /path/to/file/playbook.yml

11.3. Timesync System Roles variables

You can pass the following variable to the timesync role:

  • timesync_ntp_servers:
Role variable settingsDescription

hostname: host.example.com

Hostname or address of the server

minpoll: number

Minimum polling interval. Default: 6

maxpoll: number

Maximum polling interval. Default: 10

iburst: yes

Flag enabling fast initial synchronization. Default: no

pool: yes

Flag indicating that each resolved address of the hostname is a separate NTP server. Default: no

Additional resources

  • For a detailed reference on timesync role variables, install the rhel-system-roles package, and see the README.md or README.html files in the /usr/share/doc/rhel-system-roles/timesync directory.