90_ntp_daemon_set.yaml

apiVersion: v1
kind: ConfigMap
metadata:
  name: ntp-server
  namespace: kube-system
data:
           #first          #backup
  server: "de.pool.ntp.org pool.ntp.org"
  syncInterval: "60"
---
### Tested for OS-Systems:
#- flatcar
#- ubuntu 20.04
apiVersion: apps/v1
kind: DaemonSet
metadata:
  name: ntp-sync
  namespace: kube-system
  labels:
    app: ntp-sync
spec:
  selector:
    matchLabels:
      app: ntp-sync
  template:
    metadata:
      labels:
        app: ntp-sync
    spec:
      tolerations:
        - key: node-role.kubernetes.io/master
          effect: NoSchedule
        - effect: NoExecute
          operator: Exists
        - effect: NoSchedule
          operator: Exists
      hostPID: true
      hostNetwork: true
      containers:
        - name: ntp-sync
          #{{ Registry "gcr.io" }}/
          image: quay.io/kubermatic/util:1.4.1
          command:
            - /bin/sh
          args:
            - -c
            - nsenter -t 1 -m -u -i -n -p -- sh -c 'if test -f /usr/sbin/ntpdate; then echo installed; else /usr/bin/apt-get update && /usr/bin/apt-get -y install ntpdate; fi && while true; do ntpdate $NTP_SERVER && sleep $INTERVAL; done'
          securityContext:
            privileged: true
          env:
            - name: NTP_SERVER
              valueFrom:
                configMapKeyRef:
                  name: ntp-server
                  key: server
            - name: INTERVAL
              valueFrom:
                configMapKeyRef:
                  name: ntp-server
                  key: syncInterval
      terminationGracePeriodSeconds: 10