nodelocaldns.go

// Copyright (c) 2021 SAP SE or an SAP affiliate company. All rights reserved. This file is licensed under the Apache Software License, v. 2 except as noted otherwise in the LICENSE file
//
// 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 botanist

import (
	"context"
	"strconv"

	v1beta1constants "github.com/gardener/gardener/pkg/apis/core/v1beta1/constants"
	v1beta1helper "github.com/gardener/gardener/pkg/apis/core/v1beta1/helper"
	"github.com/gardener/gardener/pkg/operation/botanist/component/nodelocaldns"
	"github.com/gardener/gardener/pkg/utils/images"
	"github.com/gardener/gardener/pkg/utils/imagevector"

	corev1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"sigs.k8s.io/controller-runtime/pkg/client"
)

// DefaultNodeLocalDNS returns a deployer for the node-local-dns.
func (b *Botanist) DefaultNodeLocalDNS() (nodelocaldns.Interface, error) {
	image, err := b.ImageVector.FindImage(images.ImageNameNodeLocalDns, imagevector.RuntimeVersion(b.ShootVersion()), imagevector.TargetVersion(b.ShootVersion()))
	if err != nil {
		return nil, err
	}

	// The node-local-dns interface cannot bind the kube-dns cluster IP since the interface
	// used for IPVS load-balancing already uses this address.
	clusterDNS := "__PILLAR__CLUSTER__DNS__"
	dnsServer := ""
	if b.Shoot.IPVSEnabled() {
		clusterDNS = b.Shoot.Networks.CoreDNS.String()
	} else {
		dnsServer = b.Shoot.Networks.CoreDNS.String()
	}

	return nodelocaldns.New(
		b.SeedClientSet.Client(),
		b.Shoot.SeedNamespace,
		nodelocaldns.Values{
			Image:                 image.String(),
			VPAEnabled:            b.Shoot.WantsVerticalPodAutoscaler,
			ForceTcpToClusterDNS:  v1beta1helper.IsTCPEnforcedForNodeLocalDNSToClusterDNS(b.Shoot.GetInfo().Spec.SystemComponents, b.Shoot.GetInfo().Annotations),
			ForceTcpToUpstreamDNS: v1beta1helper.IsTCPEnforcedForNodeLocalDNSToUpstreamDNS(b.Shoot.GetInfo().Spec.SystemComponents, b.Shoot.GetInfo().Annotations),
			ClusterDNS:            clusterDNS,
			DNSServer:             dnsServer,
			PSPDisabled:           b.Shoot.PSPDisabled,
			KubernetesVersion:     b.Shoot.KubernetesVersion,
		},
	), nil
}

// ReconcileNodeLocalDNS deploys or destroys the node-local-dns component depending on whether it is enabled for the Shoot.
func (b *Botanist) ReconcileNodeLocalDNS(ctx context.Context) error {
	if b.Shoot.NodeLocalDNSEnabled {
		return b.Shoot.Components.SystemComponents.NodeLocalDNS.Deploy(ctx)
	}

	if stillDesired, err := b.isNodeLocalDNSStillDesired(ctx); err != nil {
		return err
	} else if stillDesired {
		// Leave NodeLocalDNS components in the cluster until all nodes have been rolled
		return nil
	}

	return b.Shoot.Components.SystemComponents.NodeLocalDNS.Destroy(ctx)
}

// isNodeLocalDNSStillDesired indicates whether any node still requires node-local-dns components.
func (b *Botanist) isNodeLocalDNSStillDesired(ctx context.Context) (bool, error) {
	nodeList := &metav1.PartialObjectMetadataList{}
	nodeList.SetGroupVersionKind(corev1.SchemeGroupVersion.WithKind("NodeList"))
	if err := b.ShootClientSet.Client().List(ctx, nodeList, client.Limit(1), client.MatchingLabels{
		v1beta1constants.LabelNodeLocalDNS: strconv.FormatBool(true),
	}); err != nil {
		return false, err
	}

	return len(nodeList.Items) > 0, nil
}