The output produced will look something like this: rvice - Network Time Synchronization Timesyncd itself is still a normal service, so you can check its status in more detail using: systemctl status systemd-timesyncd If chrony is running it will automatically switch to: īy using timedatectl, an admin can control the timezone, how the system clock should relate to the hwclock and whether permanent synchronisation should be enabled. The current status of time and time configuration via timedatectl and timesyncd can be checked with timedatectl status, which will produce output like this: Local time: Fr 08:47:13 UTC If you require a one-shot time check (without setting the time), use: chronyd -Q If you require a one-shot sync, use: chronyd -q But if you had one of a few known special ntpdate use cases, consider the following: timesyncd will generally do the right thing keeping your time in sync, and chrony will help with more complex cases. Ntpdate is now considered deprecated in favor of timedatectl (or chrony) and is no longer installed by default. However, it also implies that on an upgrade from a former release, ntp/ ntpdate might still be installed and therefore renders the new systemd-based services disabled. While use of ntpd is no longer recommended, this also still applies to ntpd being installed to retain any previous behavior/config that you had through an upgrade. This ensures that no two time syncing services are fighting. If chrony is installed, timedatectl steps back to let chrony do the timekeeping. It also stores time updates locally, so that after reboots the time monotonically advances (if applicable). So, on top of the one-shot action that ntpdate provided on boot and network activation, timesyncd now regularly checks and keeps your local time in sync. Timesyncd is available by default and replaces not only ntpdate, but also the client portion of chrony (formerly ntpd). Since Ubuntu 16.04, timedatectl/ timesyncd (which are part of systemd) replace most of ntpdate/ ntp. Luckily, all that complexity is hidden from you!īy default, Ubuntu uses timedatectl/ timesyncd to synchronise time and users can optionally use chrony to serve the Network Time Protocol. It has to factor out communication delays and adjust the time in a way that does not upset all the other processes that run on the server. The client software is also a lot more complex than you might think. There are tiers of NTP servers, with the tier one NTP servers connected to atomic clocks, and tier two and three servers spreading the load of actually handling requests across the Internet. Basically, a client requests the current time from a server, and uses it to set its own clock.īehind this simple description, there is a lot of complexity. Network Time Protocol (NTP) is a networking protocol for synchronising time over a network. Multi-node configuration with Docker-Composeĭistributed Replicated Block Device (DRBD)
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