improve NTP package conflict handling (#12212)

Signed-off-by: bo.jiang <bo.jiang@daocloud.io>

roles/kubespray_defaults/defaults/main/main.yml

@@ -770,3 +770,20 @@ system_upgrade_reboot: on-upgrade  # never, always
 
 # Enables or disables the scheduler plugins.
 scheduler_plugins_enabled: false
+
+## NTP Settings
+# Start the ntpd or chrony service and enable it at system boot.
+ntp_enabled: false
+
+# TODO: Refactor NTP package selection to integrate with the general package installation system
+# instead of using a separate variable approach
+
+# The package to install which provides NTP functionality.
+# The default is ntp for most platforms, or chrony on RHEL/CentOS 7 and later.
+# The ntp_package can be one of ['ntp', 'ntpsec', 'chrony']
+ntp_package: >-
+      {% if ansible_os_family == "RedHat" -%}
+      chrony
+      {%- else -%}
+      ntp
+      {%- endif -%}