legacy.go

/*
Copyright 2018 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 validation

import (
	"fmt"
	"net"
	"strings"

	"k8s.io/apimachinery/pkg/util/validation"
	"k8s.io/apimachinery/pkg/util/validation/field"
	"k8s.io/kops/pkg/apis/kops"
	"k8s.io/kops/pkg/apis/kops/util"
	"k8s.io/kops/pkg/featureflag"
	"k8s.io/kops/pkg/model/components"
	"k8s.io/kops/pkg/util/subnet"
	"k8s.io/kops/upup/pkg/fi"

	"github.com/blang/semver"
)

// legacy contains validation functions that don't match the apimachinery style

// ValidateCluster is responsible for checking the validity of the Cluster spec
func ValidateCluster(c *kops.Cluster, strict bool) *field.Error {
	fieldSpec := field.NewPath("spec")
	var err error

	// kubernetesRelease is the version with only major & minor fields
	var kubernetesRelease semver.Version

	// KubernetesVersion
	if c.Spec.KubernetesVersion == "" {
		return field.Required(fieldSpec.Child("KubernetesVersion"), "")
	}

	sv, err := util.ParseKubernetesVersion(c.Spec.KubernetesVersion)
	if err != nil {
		return field.Invalid(fieldSpec.Child("KubernetesVersion"), c.Spec.KubernetesVersion, "unable to determine kubernetes version")
	}
	kubernetesRelease = semver.Version{Major: sv.Major, Minor: sv.Minor}

	if c.ObjectMeta.Name == "" {
		return field.Required(field.NewPath("Name"), "Cluster Name is required (e.g. --name=mycluster.myzone.com)")
	}

	{
		// Must be a dns name
		errs := validation.IsDNS1123Subdomain(c.ObjectMeta.Name)
		if len(errs) != 0 {
			return field.Invalid(field.NewPath("Name"), c.ObjectMeta.Name, fmt.Sprintf("Cluster Name must be a valid DNS name (e.g. --name=mycluster.myzone.com) errors: %s", strings.Join(errs, ", ")))
		}

		if !strings.Contains(c.ObjectMeta.Name, ".") {
			// Tolerate if this is a cluster we are importing for upgrade
			if c.ObjectMeta.Annotations[kops.AnnotationNameManagement] != kops.AnnotationValueManagementImported {
				return field.Invalid(field.NewPath("Name"), c.ObjectMeta.Name, "Cluster Name must be a fully-qualified DNS name (e.g. --name=mycluster.myzone.com)")
			}
		}
	}

	if c.Spec.Assets != nil && c.Spec.Assets.ContainerProxy != nil && c.Spec.Assets.ContainerRegistry != nil {
		return field.Forbidden(fieldSpec.Child("Assets", "ContainerProxy"), "ContainerProxy cannot be used in conjunction with ContainerRegistry as represent mutually exclusive concepts. Please consult the documentation for details.")
	}

	if c.Spec.CloudProvider == "" {
		return field.Required(fieldSpec.Child("CloudProvider"), "")
	}

	requiresSubnets := true
	requiresNetworkCIDR := true
	requiresSubnetCIDR := true
	switch kops.CloudProviderID(c.Spec.CloudProvider) {
	case kops.CloudProviderBareMetal:
		requiresSubnets = false
		requiresSubnetCIDR = false
		requiresNetworkCIDR = false
		if c.Spec.NetworkCIDR != "" {
			return field.Invalid(fieldSpec.Child("NetworkCIDR"), c.Spec.NetworkCIDR, "NetworkCIDR should not be set on bare metal")
		}

	case kops.CloudProviderGCE:
		requiresNetworkCIDR = false
		if c.Spec.NetworkCIDR != "" {
			return field.Invalid(fieldSpec.Child("NetworkCIDR"), c.Spec.NetworkCIDR, "NetworkCIDR should not be set on GCE")
		}
		requiresSubnetCIDR = false

	case kops.CloudProviderDO:
		requiresSubnets = false
		requiresSubnetCIDR = false
		requiresNetworkCIDR = false
		if c.Spec.NetworkCIDR != "" {
			return field.Invalid(fieldSpec.Child("NetworkCIDR"), c.Spec.NetworkCIDR, "NetworkCIDR should not be set on DigitalOcean")
		}
	case kops.CloudProviderAWS:
	case kops.CloudProviderVSphere:
	case kops.CloudProviderOpenstack:
		requiresNetworkCIDR = false
		requiresSubnetCIDR = false

	default:
		return field.Invalid(fieldSpec.Child("CloudProvider"), c.Spec.CloudProvider, "CloudProvider not recognized")
	}

	if requiresSubnets && len(c.Spec.Subnets) == 0 {
		// TODO: Auto choose zones from region?
		return field.Required(fieldSpec.Child("Subnets"), "must configure at least one Subnet (use --zones)")
	}

	if strict && c.Spec.Kubelet == nil {
		return field.Required(fieldSpec.Child("Kubelet"), "Kubelet not configured")
	}
	if strict && c.Spec.MasterKubelet == nil {
		return field.Required(fieldSpec.Child("MasterKubelet"), "MasterKubelet not configured")
	}
	if strict && c.Spec.KubeControllerManager == nil {
		return field.Required(fieldSpec.Child("KubeControllerManager"), "KubeControllerManager not configured")
	}
	if kubernetesRelease.LT(semver.MustParse("1.7.0")) && c.Spec.ExternalCloudControllerManager != nil {
		return field.Invalid(fieldSpec.Child("ExternalCloudControllerManager"), c.Spec.ExternalCloudControllerManager, "ExternalCloudControllerManager is not supported in version 1.6.0 or lower")
	}
	if strict && c.Spec.KubeDNS == nil {
		return field.Required(fieldSpec.Child("KubeDNS"), "KubeDNS not configured")
	}
	if strict && c.Spec.KubeScheduler == nil {
		return field.Required(fieldSpec.Child("KubeScheduler"), "KubeScheduler not configured")
	}
	if strict && c.Spec.KubeAPIServer == nil {
		return field.Required(fieldSpec.Child("KubeAPIServer"), "KubeAPIServer not configured")
	}
	if strict && c.Spec.KubeProxy == nil {
		return field.Required(fieldSpec.Child("KubeProxy"), "KubeProxy not configured")
	}
	if strict && c.Spec.Docker == nil {
		return field.Required(fieldSpec.Child("Docker"), "Docker not configured")
	}

	// Check NetworkCIDR
	var networkCIDR *net.IPNet
	{
		if c.Spec.NetworkCIDR == "" {
			if requiresNetworkCIDR {
				return field.Required(fieldSpec.Child("NetworkCIDR"), "Cluster did not have NetworkCIDR set")
			}
		} else {
			_, networkCIDR, err = net.ParseCIDR(c.Spec.NetworkCIDR)
			if err != nil {
				return field.Invalid(fieldSpec.Child("NetworkCIDR"), c.Spec.NetworkCIDR, fmt.Sprintf("Cluster had an invalid NetworkCIDR"))
			}
		}
	}

	// Check AdditionalNetworkCIDRs
	var additionalNetworkCIDRs []*net.IPNet
	{
		if len(c.Spec.AdditionalNetworkCIDRs) > 0 {
			for _, AdditionalNetworkCIDR := range c.Spec.AdditionalNetworkCIDRs {
				_, IPNetAdditionalNetworkCIDR, err := net.ParseCIDR(AdditionalNetworkCIDR)
				if err != nil {
					return field.Invalid(fieldSpec.Child("AdditionalNetworkCIDRs"), AdditionalNetworkCIDR, fmt.Sprintf("Cluster had an invalid AdditionalNetworkCIDRs"))
				}
				additionalNetworkCIDRs = append(additionalNetworkCIDRs, IPNetAdditionalNetworkCIDR)
			}
		}
	}

	// Check NonMasqueradeCIDR
	var nonMasqueradeCIDR *net.IPNet
	{
		nonMasqueradeCIDRString := c.Spec.NonMasqueradeCIDR
		if nonMasqueradeCIDRString == "" {
			return field.Required(fieldSpec.Child("NonMasqueradeCIDR"), "Cluster did not have NonMasqueradeCIDR set")
		}
		_, nonMasqueradeCIDR, err = net.ParseCIDR(nonMasqueradeCIDRString)
		if err != nil {
			return field.Invalid(fieldSpec.Child("NonMasqueradeCIDR"), nonMasqueradeCIDRString, "Cluster had an invalid NonMasqueradeCIDR")
		}

		if networkCIDR != nil && subnet.Overlap(nonMasqueradeCIDR, networkCIDR) && c.Spec.Networking != nil && c.Spec.Networking.AmazonVPC == nil && c.Spec.Networking.LyftVPC == nil {

			return field.Invalid(fieldSpec.Child("NonMasqueradeCIDR"), nonMasqueradeCIDRString, fmt.Sprintf("NonMasqueradeCIDR %q cannot overlap with NetworkCIDR %q", nonMasqueradeCIDRString, c.Spec.NetworkCIDR))
		}

		if c.Spec.Kubelet != nil && c.Spec.Kubelet.NonMasqueradeCIDR != nonMasqueradeCIDRString {
			if strict || c.Spec.Kubelet.NonMasqueradeCIDR != "" {
				return field.Invalid(fieldSpec.Child("NonMasqueradeCIDR"), nonMasqueradeCIDRString, "Kubelet NonMasqueradeCIDR did not match cluster NonMasqueradeCIDR")
			}
		}
		if c.Spec.MasterKubelet != nil && c.Spec.MasterKubelet.NonMasqueradeCIDR != nonMasqueradeCIDRString {
			if strict || c.Spec.MasterKubelet.NonMasqueradeCIDR != "" {
				return field.Invalid(fieldSpec.Child("NonMasqueradeCIDR"), nonMasqueradeCIDRString, "MasterKubelet NonMasqueradeCIDR did not match cluster NonMasqueradeCIDR")
			}
		}
	}

	// Check ServiceClusterIPRange
	var serviceClusterIPRange *net.IPNet
	{
		serviceClusterIPRangeString := c.Spec.ServiceClusterIPRange
		if serviceClusterIPRangeString == "" {
			if strict {
				return field.Required(fieldSpec.Child("ServiceClusterIPRange"), "Cluster did not have ServiceClusterIPRange set")
			}
		} else {
			_, serviceClusterIPRange, err = net.ParseCIDR(serviceClusterIPRangeString)
			if err != nil {
				return field.Invalid(fieldSpec.Child("ServiceClusterIPRange"), serviceClusterIPRangeString, "Cluster had an invalid ServiceClusterIPRange")
			}

			if !subnet.BelongsTo(nonMasqueradeCIDR, serviceClusterIPRange) {
				return field.Invalid(fieldSpec.Child("ServiceClusterIPRange"), serviceClusterIPRangeString, fmt.Sprintf("ServiceClusterIPRange %q must be a subnet of NonMasqueradeCIDR %q", serviceClusterIPRangeString, c.Spec.NonMasqueradeCIDR))
			}

			if c.Spec.KubeAPIServer != nil && c.Spec.KubeAPIServer.ServiceClusterIPRange != serviceClusterIPRangeString {
				if strict || c.Spec.KubeAPIServer.ServiceClusterIPRange != "" {
					return field.Invalid(fieldSpec.Child("ServiceClusterIPRange"), serviceClusterIPRangeString, "KubeAPIServer ServiceClusterIPRange did not match cluster ServiceClusterIPRange")
				}
			}
		}
	}

	// Check Canal Networking Spec if used
	if c.Spec.Networking != nil && c.Spec.Networking.Canal != nil {
		action := c.Spec.Networking.Canal.DefaultEndpointToHostAction
		switch action {
		case "", "ACCEPT", "DROP", "RETURN":
		default:
			return field.Invalid(fieldSpec.Child("Networking", "Canal", "DefaultEndpointToHostAction"), action, fmt.Sprintf("Unsupported value: %s, supports 'ACCEPT', 'DROP' or 'RETURN'", action))
		}

		chainInsertMode := c.Spec.Networking.Canal.ChainInsertMode
		switch chainInsertMode {
		case "", "insert", "append":
		default:
			return field.Invalid(fieldSpec.Child("Networking", "Canal", "ChainInsertMode"), chainInsertMode, fmt.Sprintf("Unsupported value: %s, supports 'insert' or 'append'", chainInsertMode))
		}

		logSeveritySys := c.Spec.Networking.Canal.LogSeveritySys
		switch logSeveritySys {
		case "", "INFO", "DEBUG", "WARNING", "ERROR", "CRITICAL", "NONE":
		default:
			return field.Invalid(fieldSpec.Child("Networking", "Canal", "LogSeveritySys"), logSeveritySys, fmt.Sprintf("Unsupported value: %s, supports 'INFO', 'DEBUG', 'WARNING', 'ERROR', 'CRITICAL' or 'NONE'", logSeveritySys))
		}
	}

	// Check ClusterCIDR
	if c.Spec.KubeControllerManager != nil {
		var clusterCIDR *net.IPNet
		clusterCIDRString := c.Spec.KubeControllerManager.ClusterCIDR
		if clusterCIDRString != "" {
			_, clusterCIDR, err = net.ParseCIDR(clusterCIDRString)
			if err != nil {
				return field.Invalid(fieldSpec.Child("KubeControllerManager", "ClusterCIDR"), clusterCIDRString, "Cluster had an invalid KubeControllerManager.ClusterCIDR")
			}

			if !subnet.BelongsTo(nonMasqueradeCIDR, clusterCIDR) {
				return field.Invalid(fieldSpec.Child("KubeControllerManager", "ClusterCIDR"), clusterCIDRString, fmt.Sprintf("KubeControllerManager.ClusterCIDR %q must be a subnet of NonMasqueradeCIDR %q", clusterCIDRString, c.Spec.NonMasqueradeCIDR))
			}
		}
	}

	// @check the custom kubedns options are valid
	if c.Spec.KubeDNS != nil {
		if c.Spec.KubeDNS.ServerIP != "" {
			address := c.Spec.KubeDNS.ServerIP
			ip := net.ParseIP(address)
			if ip == nil {
				return field.Invalid(fieldSpec.Child("kubeDNS", "serverIP"), address, "Cluster had an invalid kubeDNS.serverIP")
			}
			if serviceClusterIPRange != nil && !serviceClusterIPRange.Contains(ip) {
				return field.Invalid(fieldSpec.Child("kubeDNS", "serverIP"), address, fmt.Sprintf("ServiceClusterIPRange %q must contain the DNS Server IP %q", c.Spec.ServiceClusterIPRange, address))
			}
			if !featureflag.ExperimentalClusterDNS.Enabled() {
				if c.Spec.Kubelet != nil && c.Spec.Kubelet.ClusterDNS != c.Spec.KubeDNS.ServerIP {
					return field.Invalid(fieldSpec.Child("kubeDNS", "serverIP"), address, "Kubelet ClusterDNS did not match cluster kubeDNS.serverIP")
				}
				if c.Spec.MasterKubelet != nil && c.Spec.MasterKubelet.ClusterDNS != c.Spec.KubeDNS.ServerIP {
					return field.Invalid(fieldSpec.Child("kubeDNS", "serverIP"), address, "MasterKubelet ClusterDNS did not match cluster kubeDNS.serverIP")
				}
			}
		}

		// @check the nameservers are valid
		for i, x := range c.Spec.KubeDNS.UpstreamNameservers {
			if ip := net.ParseIP(x); ip == nil {
				return field.Invalid(fieldSpec.Child("kubeDNS", "upstreamNameservers").Index(i), x, "Invalid nameserver given, should be a valid ip address")
			}
		}

		// @check the stubdomain if any
		if c.Spec.KubeDNS.StubDomains != nil {
			for domain, nameservers := range c.Spec.KubeDNS.StubDomains {
				if len(nameservers) <= 0 {
					return field.Invalid(fieldSpec.Child("kubeDNS", "stubDomains").Key(domain), domain, "No nameservers specified for the stub domain")
				}
				for i, x := range nameservers {
					if ip := net.ParseIP(x); ip == nil {
						return field.Invalid(fieldSpec.Child("kubeDNS", "stubDomains").Key(domain).Index(i), x, "Invalid nameserver given, should be a valid ip address")
					}
				}
			}
		}
	}

	// Check CloudProvider
	{

		var k8sCloudProvider string
		switch kops.CloudProviderID(c.Spec.CloudProvider) {
		case kops.CloudProviderAWS:
			k8sCloudProvider = "aws"
		case kops.CloudProviderGCE:
			k8sCloudProvider = "gce"
		case kops.CloudProviderDO:
			k8sCloudProvider = "external"
		case kops.CloudProviderVSphere:
			k8sCloudProvider = "vsphere"
		case kops.CloudProviderBareMetal:
			k8sCloudProvider = ""
		case kops.CloudProviderOpenstack:
			k8sCloudProvider = "openstack"
		default:
			return field.Invalid(fieldSpec.Child("CloudProvider"), c.Spec.CloudProvider, "unknown cloudprovider")
		}

		if c.Spec.Kubelet != nil && (strict || c.Spec.Kubelet.CloudProvider != "") {
			if c.Spec.Kubelet.CloudProvider != "external" && k8sCloudProvider != c.Spec.Kubelet.CloudProvider {
				return field.Invalid(fieldSpec.Child("Kubelet", "CloudProvider"), c.Spec.Kubelet.CloudProvider, "Did not match cluster CloudProvider")
			}
		}
		if c.Spec.MasterKubelet != nil && (strict || c.Spec.MasterKubelet.CloudProvider != "") {
			if c.Spec.MasterKubelet.CloudProvider != "external" && k8sCloudProvider != c.Spec.MasterKubelet.CloudProvider {
				return field.Invalid(fieldSpec.Child("MasterKubelet", "CloudProvider"), c.Spec.MasterKubelet.CloudProvider, "Did not match cluster CloudProvider")

			}
		}
		if c.Spec.KubeAPIServer != nil && (strict || c.Spec.KubeAPIServer.CloudProvider != "") {
			if c.Spec.KubeAPIServer.CloudProvider != "external" && k8sCloudProvider != c.Spec.KubeAPIServer.CloudProvider {
				return field.Invalid(fieldSpec.Child("KubeAPIServer", "CloudProvider"), c.Spec.KubeAPIServer.CloudProvider, "Did not match cluster CloudProvider")
			}
		}
		if c.Spec.KubeControllerManager != nil && (strict || c.Spec.KubeControllerManager.CloudProvider != "") {
			if c.Spec.KubeControllerManager.CloudProvider != "external" && k8sCloudProvider != c.Spec.KubeControllerManager.CloudProvider {
				return field.Invalid(fieldSpec.Child("KubeControllerManager", "CloudProvider"), c.Spec.KubeControllerManager.CloudProvider, "Did not match cluster CloudProvider")
			}
		}
	}

	// Check that the subnet CIDRs are all consistent
	{
		for i, s := range c.Spec.Subnets {
			fieldSubnet := fieldSpec.Child("Subnets").Index(i)
			if s.CIDR == "" {
				if requiresSubnetCIDR && strict {
					return field.Required(fieldSubnet.Child("CIDR"), "Subnet did not have a CIDR set")
				}
			} else {
				_, subnetCIDR, err := net.ParseCIDR(s.CIDR)
				if err != nil {
					return field.Invalid(fieldSubnet.Child("CIDR"), s.CIDR, "Subnet had an invalid CIDR")
				}

				if networkCIDR != nil && !validateSubnetCIDR(networkCIDR, additionalNetworkCIDRs, subnetCIDR) {
					return field.Invalid(fieldSubnet.Child("CIDR"), s.CIDR, fmt.Sprintf("Subnet %q had a CIDR %q that was not a subnet of the NetworkCIDR %q", s.Name, s.CIDR, c.Spec.NetworkCIDR))
				}
			}
		}
	}

	// NodeAuthorization
	if c.Spec.NodeAuthorization != nil {
		// @check the feature gate is enabled for this
		if !featureflag.EnableNodeAuthorization.Enabled() {
			return field.Invalid(field.NewPath("nodeAuthorization"), nil, "node authorization is experimental feature; set `export KOPS_FEATURE_FLAGS=EnableNodeAuthorization`")
		}
		if c.Spec.NodeAuthorization.NodeAuthorizer == nil {
			return field.Invalid(field.NewPath("nodeAuthorization"), nil, "no node authorization policy has been set")
		}
		// NodeAuthorizer
		if c.Spec.NodeAuthorization.NodeAuthorizer != nil {
			path := field.NewPath("nodeAuthorization").Child("nodeAuthorizer")
			if c.Spec.NodeAuthorization.NodeAuthorizer.Port < 0 || c.Spec.NodeAuthorization.NodeAuthorizer.Port >= 65535 {
				return field.Invalid(path.Child("port"), c.Spec.NodeAuthorization.NodeAuthorizer.Port, "invalid port")
			}
			if c.Spec.NodeAuthorization.NodeAuthorizer.Timeout != nil && c.Spec.NodeAuthorization.NodeAuthorizer.Timeout.Duration <= 0 {
				return field.Invalid(path.Child("timeout"), c.Spec.NodeAuthorization.NodeAuthorizer.Timeout, "must be greater than zero")
			}
			if c.Spec.NodeAuthorization.NodeAuthorizer.TokenTTL != nil && c.Spec.NodeAuthorization.NodeAuthorizer.TokenTTL.Duration < 0 {
				return field.Invalid(path.Child("tokenTTL"), c.Spec.NodeAuthorization.NodeAuthorizer.TokenTTL, "must be greater than or equal to zero")
			}

			// @question: we could probably just default theses settings in the model when the node-authorizer is enabled??
			if c.Spec.KubeAPIServer == nil {
				return field.Invalid(field.NewPath("kubeAPIServer"), c.Spec.KubeAPIServer, "bootstrap token authentication is not enabled in the kube-apiserver")
			}
			if c.Spec.KubeAPIServer.EnableBootstrapAuthToken == nil {
				return field.Invalid(field.NewPath("kubeAPIServer").Child("enableBootstrapAuthToken"), nil, "kube-apiserver has not been configured to use bootstrap tokens")
			}
			if !fi.BoolValue(c.Spec.KubeAPIServer.EnableBootstrapAuthToken) {
				return field.Invalid(field.NewPath("kubeAPIServer").Child("enableBootstrapAuthToken"),
					c.Spec.KubeAPIServer.EnableBootstrapAuthToken, "bootstrap tokens in the kube-apiserver has been disabled")
			}
		}
	}

	// UpdatePolicy
	if c.Spec.UpdatePolicy != nil {
		switch *c.Spec.UpdatePolicy {
		case kops.UpdatePolicyExternal:
		// Valid
		default:
			return field.Invalid(fieldSpec.Child("UpdatePolicy"), *c.Spec.UpdatePolicy, "unrecognized value for UpdatePolicy")
		}
	}

	// KubeProxy
	if c.Spec.KubeProxy != nil {
		ipvsMode := "ipvs"
		kubeProxyPath := fieldSpec.Child("KubeProxy")
		master := c.Spec.KubeProxy.Master

		if kubernetesRelease.LT(semver.MustParse("1.8.0")) && c.Spec.KubeProxy.ProxyMode == ipvsMode {
			return field.Invalid(kubeProxyPath.Child("proxyMode"), c.Spec.KubeProxy.ProxyMode, ipvsMode+" is not available pre v1.8.0")
		}
		for i, x := range c.Spec.KubeProxy.IPVSExcludeCIDRS {
			if _, _, err := net.ParseCIDR(x); err != nil {
				return field.Invalid(kubeProxyPath.Child("ipvsExcludeCIDRS").Index(i), x, "Invalid network CIDR")
			}
		}

		if master != "" && !isValidAPIServersURL(master) {
			return field.Invalid(kubeProxyPath.Child("Master"), master, "Not a valid APIServer URL")
		}
	}

	// KubeAPIServer
	if c.Spec.KubeAPIServer != nil {
		if kubernetesRelease.GTE(semver.MustParse("1.10.0")) {
			if len(c.Spec.KubeAPIServer.AdmissionControl) > 0 {
				if len(c.Spec.KubeAPIServer.DisableAdmissionPlugins) > 0 {
					return field.Invalid(fieldSpec.Child("KubeAPIServer").Child("DisableAdmissionPlugins"),
						strings.Join(c.Spec.KubeAPIServer.DisableAdmissionPlugins, ","),
						"DisableAdmissionPlugins is mutually exclusive, you cannot use both AdmissionControl and DisableAdmissionPlugins together")
				}
			}
		}
	}

	// Kubelet
	if c.Spec.Kubelet != nil {
		kubeletPath := fieldSpec.Child("Kubelet")

		if kubernetesRelease.GTE(semver.MustParse("1.6.0")) {
			// Flag removed in 1.6
			if c.Spec.Kubelet.APIServers != "" {
				return field.Invalid(
					kubeletPath.Child("APIServers"),
					c.Spec.Kubelet.APIServers,
					"api-servers flag was removed in 1.6")
			}
		} else {
			if strict && c.Spec.Kubelet.APIServers == "" {
				return field.Required(kubeletPath.Child("APIServers"), "")
			}
		}

		if kubernetesRelease.GTE(semver.MustParse("1.10.0")) {
			// Flag removed in 1.10
			if c.Spec.Kubelet.RequireKubeconfig != nil {
				return field.Invalid(
					kubeletPath.Child("requireKubeconfig"),
					*c.Spec.Kubelet.RequireKubeconfig,
					"require-kubeconfig flag was removed in 1.10.  (Please be sure you are not using a cluster config from `kops get cluster --full`)")
			}
		}

		if c.Spec.Kubelet.BootstrapKubeconfig != "" {
			if c.Spec.KubeAPIServer == nil {
				return field.Required(fieldSpec.Child("KubeAPIServer"), "bootstrap token require the NodeRestriction admissions controller")
			}
		}

		if c.Spec.Kubelet.APIServers != "" && !isValidAPIServersURL(c.Spec.Kubelet.APIServers) {
			return field.Invalid(kubeletPath.Child("APIServers"), c.Spec.Kubelet.APIServers, "Not a valid APIServer URL")
		}
	}

	// MasterKubelet
	if c.Spec.MasterKubelet != nil {
		masterKubeletPath := fieldSpec.Child("MasterKubelet")

		if kubernetesRelease.GTE(semver.MustParse("1.6.0")) {
			// Flag removed in 1.6
			if c.Spec.MasterKubelet.APIServers != "" {
				return field.Invalid(
					masterKubeletPath.Child("APIServers"),
					c.Spec.MasterKubelet.APIServers,
					"api-servers flag was removed in 1.6")
			}
		} else {
			if strict && c.Spec.MasterKubelet.APIServers == "" {
				return field.Required(masterKubeletPath.Child("APIServers"), "")
			}
		}

		if kubernetesRelease.GTE(semver.MustParse("1.10.0")) {
			// Flag removed in 1.10
			if c.Spec.MasterKubelet.RequireKubeconfig != nil {
				return field.Invalid(
					masterKubeletPath.Child("requireKubeconfig"),
					*c.Spec.MasterKubelet.RequireKubeconfig,
					"require-kubeconfig flag was removed in 1.10.  (Please be sure you are not using a cluster config from `kops get cluster --full`)")
			}
		}

		if c.Spec.MasterKubelet.APIServers != "" && !isValidAPIServersURL(c.Spec.MasterKubelet.APIServers) {
			return field.Invalid(masterKubeletPath.Child("APIServers"), c.Spec.MasterKubelet.APIServers, "Not a valid APIServer URL")
		}
	}

	// Topology support
	if c.Spec.Topology != nil {
		if c.Spec.Topology.Masters != "" && c.Spec.Topology.Nodes != "" {
			if c.Spec.Topology.Masters != kops.TopologyPublic && c.Spec.Topology.Masters != kops.TopologyPrivate {
				return field.Invalid(fieldSpec.Child("Topology", "Masters"), c.Spec.Topology.Masters, "Invalid Masters value for Topology")
			} else if c.Spec.Topology.Nodes != kops.TopologyPublic && c.Spec.Topology.Nodes != kops.TopologyPrivate {
				return field.Invalid(fieldSpec.Child("Topology", "Nodes"), c.Spec.Topology.Nodes, "Invalid Nodes value for Topology")
			}

		} else {
			return field.Required(fieldSpec.Child("Masters"), "Topology requires non-nil values for Masters and Nodes")
		}
		if c.Spec.Topology.Bastion != nil {
			bastion := c.Spec.Topology.Bastion
			if c.Spec.Topology.Masters == kops.TopologyPublic || c.Spec.Topology.Nodes == kops.TopologyPublic {
				return field.Invalid(fieldSpec.Child("Topology", "Masters"), c.Spec.Topology.Masters, "Bastion supports only Private Masters and Nodes")
			}
			if bastion.IdleTimeoutSeconds != nil && *bastion.IdleTimeoutSeconds <= 0 {
				return field.Invalid(fieldSpec.Child("Topology", "Bastion", "IdleTimeoutSeconds"), *bastion.IdleTimeoutSeconds, "Bastion IdleTimeoutSeconds should be greater than zero")
			}
			if bastion.IdleTimeoutSeconds != nil && *bastion.IdleTimeoutSeconds > 3600 {
				return field.Invalid(fieldSpec.Child("Topology", "Bastion", "IdleTimeoutSeconds"), *bastion.IdleTimeoutSeconds, "Bastion IdleTimeoutSeconds cannot be greater than one hour")
			}

		}
	}
	// Egress specification support
	{
		for i, s := range c.Spec.Subnets {
			fieldSubnet := fieldSpec.Child("Subnets").Index(i)
			if s.Egress != "" && !strings.HasPrefix(s.Egress, "nat-") && !strings.HasPrefix(s.Egress, "i-") {
				return field.Invalid(fieldSubnet.Child("Egress"), s.Egress, "egress must be of type NAT Gateway or NAT EC2 Instance")
			}
			if s.Egress != "" && !(s.Type == "Private") {
				return field.Invalid(fieldSubnet.Child("Egress"), s.Egress, "egress can only be specified for Private subnets")
			}
		}
	}

	// Etcd
	{
		fieldEtcdClusters := fieldSpec.Child("EtcdClusters")

		if len(c.Spec.EtcdClusters) == 0 {
			return field.Required(fieldEtcdClusters, "")
		}
		for i, x := range c.Spec.EtcdClusters {
			if err := validateEtcdClusterSpecLegacy(x, fieldEtcdClusters.Index(i)); err != nil {
				return err
			}
		}
		if err := validateEtcdTLS(c.Spec.EtcdClusters, fieldEtcdClusters); err != nil {
			return err
		}
		if err := validateEtcdStorage(c.Spec.EtcdClusters, fieldEtcdClusters); err != nil {
			return err
		}
	}

	if kubernetesRelease.GTE(semver.MustParse("1.4.0")) {
		if c.Spec.Networking != nil && c.Spec.Networking.Classic != nil {
			return field.Invalid(fieldSpec.Child("Networking"), "classic", "classic networking is not supported with kubernetes versions 1.4 and later")
		}
	}

	if c.Spec.Networking != nil && (c.Spec.Networking.AmazonVPC != nil || c.Spec.Networking.LyftVPC != nil) &&
		c.Spec.CloudProvider != "aws" {
		return field.Invalid(fieldSpec.Child("Networking"), "amazon-vpc-routed-eni", "amazon-vpc-routed-eni networking is supported only in AWS")
	}

	if kubernetesRelease.LT(semver.MustParse("1.7.0")) {
		if c.Spec.Networking != nil && c.Spec.Networking.Romana != nil {
			return field.Invalid(fieldSpec.Child("Networking"), "romana", "romana networking is not supported with kubernetes versions 1.6 or lower")
		}

		if c.Spec.Networking != nil && c.Spec.Networking.AmazonVPC != nil {
			return field.Invalid(fieldSpec.Child("Networking"), "amazon-vpc-routed-eni", "amazon-vpc-routed-eni networking is not supported with kubernetes versions 1.6 or lower")
		}

		if c.Spec.Networking != nil && c.Spec.Networking.LyftVPC != nil {
			return field.Invalid(fieldSpec.Child("Networking"), "cni-ipvlan-vpc-k8s", "cni-ipvlan-vpc-k8s networking is not supported with kubernetes versions 1.6 or lower")
		}
	}

	// Cilium specific validation rules
	if err := validateCilium(c); err != nil {
		return err
	}

	if errs := newValidateCluster(c); len(errs) != 0 {
		return errs[0]
	}

	return nil
}

// validateSubnetCIDR is responsible for validating subnets are part of the CIRDs assigned to the cluster.
func validateSubnetCIDR(networkCIDR *net.IPNet, additionalNetworkCIDRs []*net.IPNet, subnetCIDR *net.IPNet) bool {
	if subnet.BelongsTo(networkCIDR, subnetCIDR) {
		return true
	}

	for _, additionalNetworkCIDR := range additionalNetworkCIDRs {
		if subnet.BelongsTo(additionalNetworkCIDR, subnetCIDR) {
			return true
		}
	}

	return false
}

// validateEtcdClusterSpecLegacy is responsible for validating the etcd cluster spec
func validateEtcdClusterSpecLegacy(spec *kops.EtcdClusterSpec, fieldPath *field.Path) *field.Error {
	if spec.Name == "" {
		return field.Required(fieldPath.Child("Name"), "EtcdCluster did not have name")
	}
	if len(spec.Members) == 0 {
		return field.Required(fieldPath.Child("Members"), "No members defined in etcd cluster")
	}
	if (len(spec.Members) % 2) == 0 {
		// Not technically a requirement, but doesn't really make sense to allow
		return field.Invalid(fieldPath.Child("Members"), len(spec.Members), "Should be an odd number of master-zones for quorum. Use --zones and --master-zones to declare node zones and master zones separately")
	}
	if err := validateEtcdVersion(spec, fieldPath, nil); err != nil {
		return err
	}
	for _, m := range spec.Members {
		if err := validateEtcdMemberSpec(m, fieldPath); err != nil {
			return err
		}
	}

	return nil
}

// validateEtcdTLS checks the TLS settings for etcd are valid
func validateEtcdTLS(specs []*kops.EtcdClusterSpec, fieldPath *field.Path) *field.Error {
	var usingTLS int
	for _, x := range specs {
		if x.EnableEtcdTLS {
			usingTLS++
		}
	}
	// check both clusters are using tls if one us enabled
	if usingTLS > 0 && usingTLS != len(specs) {
		return field.Invalid(fieldPath.Index(0).Child("EnableEtcdTLS"), false, "Both etcd clusters must have TLS enabled or none at all")
	}

	return nil
}

// validateEtcdStorage is responsible for checks version are identical
func validateEtcdStorage(specs []*kops.EtcdClusterSpec, fieldPath *field.Path) *field.Error {
	version := specs[0].Version
	for i, x := range specs {
		if x.Version != "" && x.Version != version {
			return field.Invalid(fieldPath.Index(i).Child("Version"), x.Version, fmt.Sprintf("cluster: %q, has a different storage versions: %q, both must be the same", x.Name, x.Version))
		}
	}

	return nil
}

// validateEtcdVersion is responsible for validating the storage version of etcd
// @TODO semvar package doesn't appear to ignore a 'v' in v1.1.1 should could be a problem later down the line
func validateEtcdVersion(spec *kops.EtcdClusterSpec, fieldPath *field.Path, minimalVersion *semver.Version) *field.Error {
	// @check if the storage is specified, thats is valid

	if minimalVersion == nil {
		v := semver.MustParse("0.0.0")
		minimalVersion = &v
	}

	version := spec.Version
	if spec.Version == "" {
		version = components.DefaultEtcd2Version
	}

	sem, err := semver.Parse(strings.TrimPrefix(version, "v"))
	if err != nil {
		return field.Invalid(fieldPath.Child("Version"), version, "the storage version is invalid")
	}

	// we only support v3 and v2 for now
	if sem.Major == 3 || sem.Major == 2 {
		if sem.LT(*minimalVersion) {
			return field.Invalid(fieldPath.Child("Version"), version, fmt.Sprintf("minimal version required is %s", minimalVersion.String()))
		}
		return nil
	}

	return field.Invalid(fieldPath.Child("Version"), version, "unsupported storage version, we only support major versions 2 and 3")
}

// validateEtcdMemberSpec is responsible for validate the cluster member
func validateEtcdMemberSpec(spec *kops.EtcdMemberSpec, fieldPath *field.Path) *field.Error {
	if spec.Name == "" {
		return field.Required(fieldPath.Child("Name"), "EtcdMember did not have Name")
	}

	if fi.StringValue(spec.InstanceGroup) == "" {
		return field.Required(fieldPath.Child("InstanceGroup"), "EtcdMember did not have InstanceGroup")
	}

	return nil
}

func validateCilium(c *kops.Cluster) *field.Error {
	if c.Spec.Networking != nil && c.Spec.Networking.Cilium != nil {
		specPath := field.NewPath("Spec")

		minimalKubeVersion := semver.MustParse("1.7.0")
		kubeVersion := semver.MustParse(c.Spec.KubernetesVersion)
		if kubeVersion.LT(minimalKubeVersion) {
			return field.Invalid(specPath.Child("KubernetesVersion"), c.Spec.KubernetesVersion, "Cilium needs at least Kubernetes 1.7")
		}

		minimalVersion := semver.MustParse("3.1.0")
		path := specPath.Child("EtcdClusters").Index(0)
		if err := validateEtcdVersion(c.Spec.EtcdClusters[0], path, &minimalVersion); err != nil {
			return err
		}
	}
	return nil
}

// DeepValidate is responsible for validating the instancegroups within the cluster spec
func DeepValidate(c *kops.Cluster, groups []*kops.InstanceGroup, strict bool) error {
	if err := ValidateCluster(c, strict); err != nil {
		return err
	}

	if len(groups) == 0 {
		return fmt.Errorf("must configure at least one InstanceGroup")
	}

	masterGroupCount := 0
	nodeGroupCount := 0
	for _, g := range groups {
		if g.IsMaster() {
			masterGroupCount++
		} else {
			nodeGroupCount++
		}
	}

	if masterGroupCount == 0 {
		return fmt.Errorf("must configure at least one Master InstanceGroup")
	}

	if nodeGroupCount == 0 {
		return fmt.Errorf("must configure at least one Node InstanceGroup")
	}

	for _, g := range groups {
		err := CrossValidateInstanceGroup(g, c, strict)
		if err != nil {
			return err
		}

		// Additional cloud-specific validation rules,
		// such as making sure that identifiers match the expected formats for the given cloud
		switch kops.CloudProviderID(c.Spec.CloudProvider) {
		case kops.CloudProviderAWS:
			errs := awsValidateInstanceGroup(g)
			if len(errs) != 0 {
				return errs[0]
			}
		}
	}

	return nil
}