helm: revert parts of CoreDNS Helm chart packaging (#3366)

* Revert "helm: fix kubeadm bugs caused by CoreDNS installation (#3353)"

This reverts commit 8ef5ea2.

* Revert "helm: manage CoreDNS addon as Helm chart (#3236)"

This reverts commit 97c77e2.

* upgrade-agent: ignore CoreDNS preflight errors

bootstrapper/internal/kubernetes/k8sapi/k8sutil.go

@@ -48,6 +48,7 @@ type Client interface {
 	AddNodeSelectorsToDeployment(ctx context.Context, selectors map[string]string, name string, namespace string) error
 	ListAllNamespaces(ctx context.Context) (*corev1.NamespaceList, error)
 	AnnotateNode(ctx context.Context, nodeName, annotationKey, annotationValue string) error
+	EnforceCoreDNSSpread(ctx context.Context) error
 	PatchFirstNodePodCIDR(ctx context.Context, firstNodePodCIDR string) error
 }
 
@@ -149,7 +150,7 @@ func (k *KubernetesUtil) InitCluster(
 
 	// initialize the cluster
 	log.Info("Initializing the cluster using kubeadm init")
-	skipPhases := "--skip-phases=preflight,certs,addon/coredns"
+	skipPhases := "--skip-phases=preflight,certs"
 	if !conformanceMode {
 		skipPhases += ",addon/kube-proxy"
 	}

bootstrapper/internal/kubernetes/kubernetes.go

@@ -165,6 +165,10 @@ func (k *KubeWrapper) InitCluster(
 		return nil, fmt.Errorf("waiting for Kubernetes API to be available: %w", err)
 	}
 
+	if err := k.client.EnforceCoreDNSSpread(ctx); err != nil {
+		return nil, fmt.Errorf("configuring CoreDNS deployment: %w", err)
+	}
+
 	// Setup the K8s components ConfigMap.
 	k8sComponentsConfigMap, err := k.setupK8sComponentsConfigMap(ctx, kubernetesComponents, versionString)
 	if err != nil {

cli/internal/cmd/apply.go

@@ -428,9 +428,6 @@ func (a *applyCmd) apply(
 		if err := a.runHelmApply(cmd, conf, stateFile, upgradeDir); err != nil {
 			return err
 		}
-		if err := a.applier.CleanupCoreDNSResources(cmd.Context()); err != nil {
-			return fmt.Errorf("cleaning up CoreDNS: %w", err)
-		}
 	}
 
 	// Upgrade node image
@@ -850,7 +847,6 @@ type applier interface {
 	// methods required to install/upgrade Helm charts
 
 	AnnotateCoreDNSResources(context.Context) error
-	CleanupCoreDNSResources(context.Context) error
 	PrepareHelmCharts(
 		flags helm.Options, state *state.State, serviceAccURI string, masterSecret uri.MasterSecret,
 	) (helm.Applier, bool, error)

cli/internal/cmd/apply_test.go

@@ -554,7 +554,6 @@ func (s *stubConstellApplier) Init(context.Context, atls.Validator, *state.State
 
 type helmApplier interface {
 	AnnotateCoreDNSResources(context.Context) error
-	CleanupCoreDNSResources(ctx context.Context) error
 	PrepareHelmCharts(
 		flags helm.Options, stateFile *state.State, serviceAccURI string, masterSecret uri.MasterSecret,
 	) (

cli/internal/cmd/applyhelm.go

@@ -42,7 +42,6 @@ func (a *applyCmd) runHelmApply(cmd *cobra.Command, conf *config.Config, stateFi
 		HelmWaitMode:        a.flags.helmWaitMode,
 		ApplyTimeout:        a.flags.helmTimeout,
 		AllowDestructive:    helm.DenyDestructive,
-		ServiceCIDR:         conf.ServiceCIDR,
 	}
 	if conf.Provider.OpenStack != nil {
 		var deployYawolLoadBalancer bool

cli/internal/cmd/init_test.go

@@ -282,10 +282,6 @@ func (s stubHelmApplier) AnnotateCoreDNSResources(_ context.Context) error {
 	return nil
 }
 
-func (s stubHelmApplier) CleanupCoreDNSResources(_ context.Context) error {
-	return nil
-}
-
 func (s stubHelmApplier) PrepareHelmCharts(
 	_ helm.Options, _ *state.State, _ string, _ uri.MasterSecret,
 ) (helm.Applier, bool, error) {

cli/internal/cmd/upgradeapply_test.go

@@ -379,10 +379,6 @@ func (m *mockApplier) AnnotateCoreDNSResources(_ context.Context) error {
 	return nil
 }
 
-func (m *mockApplier) CleanupCoreDNSResources(_ context.Context) error {
-	return nil
-}
-
 func (m *mockApplier) PrepareHelmCharts(
 	helmOpts helm.Options, stateFile *state.State, str string, masterSecret uri.MasterSecret,
 ) (helm.Applier, bool, error) {

go.mod

@@ -192,8 +192,6 @@ require (
 	github.com/cloudflare/circl v1.3.7 // indirect
 	github.com/containerd/containerd v1.7.12 // indirect
 	github.com/containerd/log v0.1.0 // indirect
-	github.com/coredns/caddy v1.1.1 // indirect
-	github.com/coredns/corefile-migration v1.0.21 // indirect
 	github.com/coreos/go-semver v0.3.1 // indirect
 	github.com/cpuguy83/go-md2man/v2 v2.0.4 // indirect
 	github.com/cyberphone/json-canonicalization v0.0.0-20220623050100-57a0ce2678a7 // indirect

internal/constellation/helm.go

@@ -60,21 +60,6 @@ func (a *Applier) AnnotateCoreDNSResources(ctx context.Context) error {
 	return nil
 }
 
-// CleanupCoreDNSResources removes CoreDNS resources that are not managed by Helm.
-//
-// This is only required when CoreDNS was installed by kubeadm directly.
-// TODO(burgerdev): remove after v2.19 is released.
-func (a *Applier) CleanupCoreDNSResources(ctx context.Context) error {
-	err := a.dynamicClient.
-		Resource(schema.GroupVersionResource{Group: "", Version: "v1", Resource: "configmaps"}).
-		Namespace("kube-system").
-		Delete(ctx, "coredns", v1.DeleteOptions{})
-	if !k8serrors.IsNotFound(err) {
-		return err
-	}
-	return nil
-}
-
 // PrepareHelmCharts loads Helm charts for Constellation and returns an executor to apply them.
 func (a *Applier) PrepareHelmCharts(
 	flags helm.Options, state *state.State, serviceAccURI string, masterSecret uri.MasterSecret,

internal/constellation/helm/BUILD.bazel

@@ -465,14 +465,6 @@ go_library(
         "charts/cert-manager/templates/cainjector-config.yaml",
         "charts/cert-manager/templates/extras-objects.yaml",
         "charts/cert-manager/templates/podmonitor.yaml",
-        "charts/coredns/Chart.yaml",
-        "charts/coredns/values.yaml",
-        "charts/coredns/templates/clusterrole.yaml",
-        "charts/coredns/templates/clusterrolebinding.yaml",
-        "charts/coredns/templates/configmap.yaml",
-        "charts/coredns/templates/deployment.yaml",
-        "charts/coredns/templates/service.yaml",
-        "charts/coredns/templates/serviceaccount.yaml",
     ],
     importpath = "github.com/edgelesssys/constellation/v2/internal/constellation/helm",
     visibility = ["//:__subpackages__"],
@@ -500,7 +492,6 @@ go_library(
         "@io_k8s_client_go//restmapper",
         "@io_k8s_client_go//tools/clientcmd",
         "@io_k8s_client_go//util/retry",
-        "@io_k8s_kubernetes//cmd/kubeadm/app/constants",
         "@sh_helm_helm_v3//pkg/action",
         "@sh_helm_helm_v3//pkg/chart",
         "@sh_helm_helm_v3//pkg/chart/loader",