Add an option to skip NTP installation

docs/cluster_spec.md

@@ -1293,3 +1293,14 @@ spec:
 
 In the case of containerd, the cgroup-driver is dependant on the cgroup driver of kubelet. To use cgroupfs, just update the
 cgroupDriver of kubelet to use cgroupfs.
+
+## NTP
+
+The installation and the configuration of NTP can be skipped by setting `managed` to `false`.
+
+```yaml
+spec:
+  ntp:
+    managed: false
+```
+

k8s/crds/kops.k8s.io_clusters.yaml

@@ -3913,6 +3913,15 @@ spec:
                   NonMasqueradeCIDR is the CIDR for the internal k8s network (on which
                   pods & services live) It cannot overlap ServiceClusterIPRange
                 type: string
+              ntp:
+                description: NTPConfig is the configuration for NTP.
+                properties:
+                  managed:
+                    description: Managed controls if the NTP configuration is managed
+                      by kOps. The NTP configuration task is skipped if this is set
+                      to false.
+                    type: boolean
+                type: object
               podCIDR:
                 description: PodCIDR is the CIDR from which we allocate IPs for pods
                 type: string

nodeup/pkg/model/ntp.go

@@ -34,6 +34,11 @@ var _ fi.ModelBuilder = &NTPBuilder{}
 
 // Build is responsible for configuring NTP
 func (b *NTPBuilder) Build(c *fi.ModelBuilderContext) error {
+	if !b.managed() {
+		klog.Infof("Managed is set to false; won't install NTP")
+		return nil
+	}
+
 	switch b.Distribution {
 	case distributions.DistributionContainerOS:
 		klog.Infof("Detected ContainerOS; won't install ntp")
@@ -112,3 +117,11 @@ NTP=` + host + `
 		Mode:     s("0644"),
 	}
 }
+
+// managed determines if kops should manage the installation and configuration of NTP.
+func (b *NTPBuilder) managed() bool {
+	n := b.Cluster.Spec.NTP
+	// Consider the NTP is managed when the NTP configuration
+	// is not specified (for backward compatibility).
+	return n == nil || n.Managed == nil || *n.Managed
+}

pkg/apis/kops/cluster.go

@@ -159,6 +159,7 @@ type ClusterSpec struct {
 	MasterKubelet                  *KubeletConfigSpec            `json:"masterKubelet,omitempty"`
 	CloudConfig                    *CloudConfiguration           `json:"cloudConfig,omitempty"`
 	ExternalDNS                    *ExternalDNSConfig            `json:"externalDns,omitempty"`
+	NTP                            *NTPConfig                    `json:"ntp,omitempty"`
 
 	// NodeTerminationHandler determines the cluster autoscaler configuration.
 	NodeTerminationHandler *NodeTerminationHandlerConfig `json:"nodeTerminationHandler,omitempty"`

pkg/apis/kops/ntpconfig.go

@@ -0,0 +1,24 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kops
+
+// NTPConfig is the configuration for NTP.
+type NTPConfig struct {
+	// Managed controls if the NTP configuration is managed by kOps.
+	// The NTP configuration task is skipped if this is set to false.
+	Managed *bool `json:"managed,omitempty"`
+}

pkg/apis/kops/v1alpha2/cluster.go

@@ -158,6 +158,7 @@ type ClusterSpec struct {
 	MasterKubelet                  *KubeletConfigSpec            `json:"masterKubelet,omitempty"`
 	CloudConfig                    *CloudConfiguration           `json:"cloudConfig,omitempty"`
 	ExternalDNS                    *ExternalDNSConfig            `json:"externalDns,omitempty"`
+	NTP                            *NTPConfig                    `json:"ntp,omitempty"`
 
 	// NodeTerminationHandler determines the cluster autoscaler configuration.
 	NodeTerminationHandler *NodeTerminationHandlerConfig `json:"nodeTerminationHandler,omitempty"`

pkg/apis/kops/v1alpha2/ntpconfig.go

@@ -0,0 +1,24 @@
+/*
+Copyright 2021 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package v1alpha2
+
+// NTPConfig is the configuration for NTP.
+type NTPConfig struct {
+	// Managed controls if the NTP configuration is managed by kOps.
+	// The NTP configuration task is skipped if this is set to false.
+	Managed *bool `json:"managed,omitempty"`
+}