How to synchronize the clock on an IPA installation - ntpdate or slew mode

Issue

• The objective is to synchronize the clock at boot time on a ntp server defined by its DNS name.
• In a IPA installation, the named service is managed by ipactl (ipa service).

Thus, ntpdate fails to resolve the name of the ntp server with this kind of message:

Oct  2 05:04:00 server ntpdate-wrapper: Error resolving clock1.rdu2.redhat.com: Name or service not known (-2)

• The use of the IP address instead of the name is a basic workaround.
• The second issue is that ntpd is launched with the slew mode (-x option) which does not allow to step the clock. Thus the use of ntpdate is needed.