Understanding systemd-timesyncd

Ubuntu uses systemd-timesyncd by default. It's a simple, lightweight system that's easy to configure. Before we get to that, let's take a quick look at the systemd-timesyncd.service file.

The systemd-timesyncd.service file

The [Unit] section of the /lib/systemd/system/systemd-timesyncd.service file looks like this:

[Unit]
Description=Network Time Synchronization
Documentation=man:systemd-timesyncd.service(8)
ConditionCapability=CAP_SYS_TIME
ConditionVirtualization=!container
DefaultDependencies=no
After=systemd-sysusers.service
Before=time-set.target sysinit.target shutdown.target
Conflicts=shutdown.target
Wants=time-set.target time-sync.target

Note the ConditionVirtualization=!container line. The ConditionVirtualization= part checks to see if the operating system is running in a virtualized environment. In this case, it wants to see whether it's running in a container. The ! in front of container denotes a negation. In...