Chrony NTP Client/Server

Modern NTP implementation for time synchronization. Chrony is designed for systems with intermittent network connectivity and is the default NTP client on modern Linux distributions.

Features

Fast initial time synchronization
Client mode: sync time from NTP pools/servers
Server mode: serve time to local network clients
Automatic conflict resolution with systemd-timesyncd and ntpd
Firewall integration for server mode

Usage

Client-only mode (default)

Sync time from public NTP pools, don't serve time to others:

# host_vars/example.yml
ntp_timezone: "Europe/Paris"
ntp_pools:
    - "0.fr.pool.ntp.org"
    - "1.fr.pool.ntp.org"
    - "2.fr.pool.ntp.org"
    - "3.fr.pool.ntp.org"

Server mode

Serve time to local network:

# host_vars/ntp-server.yml
ntp_timezone: "UTC"
ntp_server_enabled: true
ntp_allowed_networks:
    - 192.168.1.0/24 # Configures both chrony and firewall
    - 192.168.27.0/27

Client syncing from local server

# host_vars/client.yml
ntp_pools: [] # Don't use public pools
ntp_servers:
    - server: ntp.local.lan
      options: iburst prefer
    - server: 192.168.1.1
      options: iburst

Logging

Default: journald - Logs to systemd journal (recommended)

# View chrony logs
journalctl -u chronyd -f

Optional: File-based logging with automatic rotation

ntp_log_backend: file
ntp_log_measurements: true
ntp_log_statistics: true
ntp_log_tracking: true

Variables

See defaults/main.yml for all configuration options.

Verification

# Check chrony status
chronyc tracking

# Show current time sources
chronyc sources

# Show detailed source stats
chronyc sourcestats

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