configure core dns for internal name resolution (#317)

Signed-off-by: Manabu McCloskey <[email protected]>

pkg/build/build.go

@@ -172,6 +172,12 @@ func (b *Build) Run(ctx context.Context, recreateCluster bool) error {
 	defer os.RemoveAll(dir)
 	setupLog.V(1).Info("Created temp directory for cloning repositories", "dir", dir)
 
+	setupLog.Info("Setting up CoreDNS")
+	err = setupCoreDNS(ctx, kubeClient, b.scheme, b.cfg)
+	if err != nil {
+		return err
+	}
+
 	setupLog.V(1).Info("Running controllers")
 	if err := b.RunControllers(ctx, mgr, managerExit, dir); err != nil {
 		setupLog.Error(err, "Error running controllers")

pkg/build/coredns.go

@@ -0,0 +1,76 @@
+package build
+
+import (
+	"context"
+	"embed"
+	"fmt"
+
+	"github.com/cnoe-io/idpbuilder/pkg/k8s"
+	"github.com/cnoe-io/idpbuilder/pkg/util"
+	appsv1 "k8s.io/api/apps/v1"
+	corev1 "k8s.io/api/core/v1"
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	"k8s.io/apimachinery/pkg/runtime"
+	"sigs.k8s.io/controller-runtime/pkg/client"
+	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
+)
+
+const (
+	coreDNSTemplatePath = "templates/coredns"
+)
+
+//go:embed templates
+var templates embed.FS
+
+func setupCoreDNS(ctx context.Context, kubeClient client.Client, scheme *runtime.Scheme, templateData util.CorePackageTemplateConfig) error {
+	checkCM := &corev1.ConfigMap{
+		ObjectMeta: metav1.ObjectMeta{
+			Name:      "coredns-conf-default",
+			Namespace: "kube-system",
+		},
+	}
+	err := kubeClient.Get(ctx, client.ObjectKeyFromObject(checkCM), checkCM)
+	if err == nil {
+		return nil
+	}
+
+	objs, err := k8s.BuildCustomizedObjects("", coreDNSTemplatePath, templates, scheme, templateData)
+	if err != nil {
+		return fmt.Errorf("rendering embedded coredns files: %w", err)
+	}
+
+	for i := range objs {
+		obj := objs[i]
+		switch t := obj.(type) {
+		case *appsv1.Deployment:
+			dep := &appsv1.Deployment{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      t.Name,
+					Namespace: t.Namespace,
+				},
+			}
+			_, err = controllerutil.CreateOrUpdate(ctx, kubeClient, dep, func() error {
+				dep.Spec = t.Spec
+				return nil
+			})
+			if err != nil {
+				return fmt.Errorf("creating/updating deployment: %w", err)
+			}
+		case *corev1.ConfigMap:
+			cm := &corev1.ConfigMap{
+				ObjectMeta: metav1.ObjectMeta{
+					Name:      t.Name,
+					Namespace: t.Namespace,
+				},
+			}
+			_, err = controllerutil.CreateOrUpdate(ctx, kubeClient, cm, func() error {
+				cm.Data = t.Data
+				return nil
+			})
+			if err != nil {
+				return fmt.Errorf("creating/updating configmap: %w", err)
+			}
+		}
+	}
+	return nil
+}

pkg/build/templates/coredns/cm-coredns-custom.yaml

@@ -0,0 +1,8 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: coredns-conf-custom
+  namespace: kube-system
+data:
+  custom.conf: |
+    # insert custom rules here

pkg/build/templates/coredns/cm-coredns-default.yaml.tmpl

@@ -0,0 +1,13 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: coredns-conf-default
+  namespace: kube-system
+data:
+  default.conf: |
+    # subdomain names resolves to ingress IP. e.g. gitea.cnoe.localtest.me becomes ingress-nginx-controller.ingress-nginx.svc.cluster.local
+    rewrite stop {
+        name regex (.*).{{ .Host }} ingress-nginx-controller.ingress-nginx.svc.cluster.local
+    }
+    # host name resolves to ingress IP
+    rewrite name exact {{ .Host }} ingress-nginx-controller.ingress-nginx.svc.cluster.local

pkg/build/templates/coredns/cm-coredns.yaml

@@ -0,0 +1,30 @@
+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: coredns
+  namespace: kube-system
+data:
+  Corefile: |
+    .:53 {
+        errors
+        health {
+           lameduck 5s
+        }
+        ready
+
+        import ../coredns-configs/*.conf
+
+        kubernetes cluster.local in-addr.arpa ip6.arpa {
+           pods insecure
+           fallthrough in-addr.arpa ip6.arpa
+           ttl 30
+        }
+        prometheus :9153
+        forward . /etc/resolv.conf {
+           max_concurrent 1000
+        }
+        cache 30
+        loop
+        reload
+        loadbalance
+    }

pkg/build/templates/coredns/deployment-coredns.yaml

@@ -0,0 +1,126 @@
+apiVersion: apps/v1
+kind: Deployment
+metadata:
+  labels:
+    k8s-app: kube-dns
+  name: coredns
+  namespace: kube-system
+spec:
+  progressDeadlineSeconds: 600
+  replicas: 2
+  revisionHistoryLimit: 10
+  selector:
+    matchLabels:
+      k8s-app: kube-dns
+  strategy:
+    rollingUpdate:
+      maxSurge: 25%
+      maxUnavailable: 1
+    type: RollingUpdate
+  template:
+    metadata:
+      creationTimestamp: null
+      labels:
+        k8s-app: kube-dns
+    spec:
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+            - podAffinityTerm:
+                labelSelector:
+                  matchExpressions:
+                    - key: k8s-app
+                      operator: In
+                      values:
+                        - kube-dns
+                topologyKey: kubernetes.io/hostname
+              weight: 100
+      containers:
+        - args:
+            - -conf
+            - /etc/coredns/Corefile
+          image: registry.k8s.io/coredns/coredns:v1.11.1
+          imagePullPolicy: IfNotPresent
+          livenessProbe:
+            failureThreshold: 5
+            httpGet:
+              path: /health
+              port: 8080
+              scheme: HTTP
+            initialDelaySeconds: 60
+            periodSeconds: 10
+            successThreshold: 1
+            timeoutSeconds: 5
+          name: coredns
+          ports:
+            - containerPort: 53
+              name: dns
+              protocol: UDP
+            - containerPort: 53
+              name: dns-tcp
+              protocol: TCP
+            - containerPort: 9153
+              name: metrics
+              protocol: TCP
+          readinessProbe:
+            failureThreshold: 3
+            httpGet:
+              path: /ready
+              port: 8181
+              scheme: HTTP
+            periodSeconds: 10
+            successThreshold: 1
+            timeoutSeconds: 1
+          resources:
+            limits:
+              memory: 170Mi
+            requests:
+              cpu: 100m
+              memory: 70Mi
+          securityContext:
+            allowPrivilegeEscalation: false
+            capabilities:
+              add:
+                - NET_BIND_SERVICE
+              drop:
+                - ALL
+            readOnlyRootFilesystem: true
+          terminationMessagePath: /dev/termination-log
+          terminationMessagePolicy: File
+          volumeMounts:
+            - mountPath: /etc/coredns
+              name: config-volume
+              readOnly: true
+            - mountPath: /etc/coredns-configs
+              name: custom-configs
+              readOnly: true
+      dnsPolicy: Default
+      nodeSelector:
+        kubernetes.io/os: linux
+      priorityClassName: system-cluster-critical
+      restartPolicy: Always
+      schedulerName: default-scheduler
+      securityContext: {}
+      serviceAccount: coredns
+      serviceAccountName: coredns
+      terminationGracePeriodSeconds: 30
+      tolerations:
+        - key: CriticalAddonsOnly
+          operator: Exists
+        - effect: NoSchedule
+          key: node-role.kubernetes.io/control-plane
+      volumes:
+        - configMap:
+            defaultMode: 420
+            items:
+              - key: Corefile
+                path: Corefile
+            name: coredns
+          name: config-volume
+        - name: custom-configs
+          projected:
+            sources:
+              - configMap:
+                  name: coredns-conf-custom
+              - configMap:
+                  name: coredns-conf-default

pkg/cmd/create/root.go

@@ -19,11 +19,11 @@ import (
 
 var (
 	// Flags
-	recreateCluster           bool
-	buildName                 string
-	kubeVersion               string
-	extraPortsMapping         string
-	kindConfigPath            string
+	recreateCluster   bool
+	buildName         string
+	kubeVersion       string
+	extraPortsMapping string
+	kindConfigPath    string
 	// TODO: Remove extraPackagesDirs after 0.6.0 release
 	extraPackagesDirs         []string
 	extraPackages             []string