jontow / timesync

An ansible role which configures time synchronization

timesync

This role installs and configures an NTP and/or PTP implementation to operate as an NTP client and/or PTP slave in order to synchronize the system clock with NTP servers and/or grandmasters in PTP domains. Supported NTP/PTP implementations are chrony, ntp (the reference implementation) and linuxptp.

Warning

The role replaces the configuration of the given or detected provider service on the managed host. Previous settings will be lost, even if they are not specified in the role variables (no attempt is made to preserve or merge the previous settings, the configuration files are replaced entirely). The only setting which is preserved is the choice of provider if timesync_ntp_provider is not defined (see the description of this variable below).

Role Variables

The variables that can be passed to this role are as follows:

# List of NTP servers
timesync_ntp_servers:
  - hostname: foo.example.com   # Hostname or address of the server
    minpoll: 4                  # Minimum polling interval (default 6)
    maxpoll: 8                  # Maximum polling interval (default 10)
    iburst: yes                 # Flag enabling fast initial synchronization
                                # (default no)
    pool: no                    # Flag indicating that each resolved address
                                # of the hostname is a separate NTP server
                                # (default no)

# List of PTP domains
timesync_ptp_domains:
  - number: 0                   # PTP domain number
    interfaces: [ eth0 ]        # List of interfaces in the domain
    delay: 0.000010             # Assumed maximum network delay to the
                                # grandmaster in seconds
                                # (default 100 microsecond)
    transport: UDPv4            # Network transport: UDPv4, UDPv6, L2
                                # (default UDPv4)
    udp_ttl: 1                  # TTL for UDPv4 and UDPv6 transports
                                # (default 1)

# Flag enabling use of NTP servers provided by DHCP (default no)
timesync_dhcp_ntp_servers: no

# Minimum offset of the clock which can be corrected by stepping (default is
# specific to NTP/PTP implementation: chrony 1.0, ntp 0.128, linuxptp 0.00002).
# Zero threshold disables all steps.
timesync_step_threshold: 1.0

# Minimum number of selectable time sources required to allow synchronization
# of the clock (default 1)
timesync_min_sources: 1

# Name of the package which should be installed and configured for NTP.
# Possible values are "chrony" and "ntp". If not defined, the currently active
# or enabled service will be configured. If no service is active or enabled, a
# package specific to the system and its version will be selected.
timesync_ntp_provider: chrony

Example Playbook

Install and configure ntp to synchronize the system clock with three NTP servers:

- hosts: targets
  vars:
    timesync_ntp_servers:
      - hostname: foo.example.com
        iburst: yes
      - hostname: bar.example.com
        iburst: yes
      - hostname: baz.example.com
        iburst: yes
  roles:
    - linux-system-roles.timesync

Install and configure linuxptp to synchronize the system clock with a grandmaster in PTP domain number 0, which is accessible on interface eth0:

- hosts: targets
  vars:
    timesync_ptp_domains:
      - number: 0
        interfaces: [ eth0 ]
  roles:
    - linux-system-roles.timesync

Install and configure chrony and linuxptp to synchronize the system clock with multiple NTP servers and PTP domains for a highly accurate and resilient synchronization:

- hosts: targets
  vars:
    timesync_ntp_servers:
      - hostname: foo.example.com
        maxpoll: 6
      - hostname: bar.example.com
        maxpoll: 6
      - hostname: baz.example.com
        maxpoll: 6
    timesync_ptp_domains:
      - number: 0
        interfaces: [ eth0, eth1 ]
        transport: L2
        delay: 0.000010
      - number: 1
        interfaces: [ eth2 ]
        transport: UDPv4
        delay: 0.000010
  roles:
    - linux-system-roles.timesync