Why is NTP out of sync on servers that are hosted on Digital Ocean since the daylight saving time?

Question

Since the daylight saving time the Sensu monitor indicates that the NTP of multiple servers that run on Digital Ocean (DO) are out of sync (12.345404ms-98.338222ms):

CheckNTP WARNING: NTP offset by 34.073039ms

Discussion

Perhaps the NTP configuration is incorrect?

The NTP configuration was deviating, but now the same configuration has been applied using Geerlingguy's ntp role.
What will happen if the NTP server has been restarted?

The monitor indicated that the NTP has been synced, but in a while the issue occurs again.
What will happen if the NTP server will be stopped, the time is set manually and the ntp server will be started again?

Identical to three.
Perhaps the issue is related to the DO platform?

Unknown. No solutions were found on the internet.
What will happen if the nearest location while be chosen as a timeserver?

server 0.nl.pool.ntp.org iburst
server 1.nl.pool.ntp.org iburst
server 2.nl.pool.ntp.org iburst
server 3.nl.pool.ntp.org iburst

When the NTP server was restarted, the time was synced and later on the time was out sync again.
Do the droplets sync and later on run out of sync?

Yes that seems to be the case:

shodanshok · Answer

NTP (and SNTP) do not provide information about timezones/daylight saving. Rather, it provides a precise UTC reference clock that need to be interpreted by the client to be show in correct local times. This means that daylight saving should have absolutely no effects on NTP clock drift/skew.
Some suggestions:

what NTP client are you using? RHEL7 ships with chrony, which I found to be somewhat less accurate than plain old ntpd + ntpdate

remove the iburst option from your ntp config file and restart your NTP client

be sure to use NTP servers which are reacheable with low RTT (ie: you can ping fast)

check for network congestion

be sure to read NTP manpage as it really has some great documentation

Why is NTP out of sync on servers that are hosted on Digital Ocean since the daylight saving time?

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