Operations grimoire/NTP

NTP allows to sync time. That's especially important for accurate logs and TLS certificates.

Recommended NTP servers

There is a CC list of servers by country. France makes sense for most servers to use the country of the datacenter where the server is located.

By OS

NTP is configured in core.

FreeBSD

We use ntpd service. Each day, drift from NTP servers is checked by periodic 480.status-ntpd.

Linux

Chrony service is used.

Troubleshoot

Update leap seconds

Leap seconds file isn't maintained any more by NTP package (see upstream issue)

ntpq: read: Connection refused

Reported as T2192. The ntpq command queries a specific NTP server, here localhost:123. If the connection can't be established, it probably means ntpd service isn't started.

NTP status: ntpq: read: Connection refused

Solution: service ntpd start

References

NTP

• NTP servers in France
• [Bug 3898 - update leap seconds file

Chrony

• [1]