Merge pull request #6657 from kameshsampath/registry-aliases

New addon: registry-aliases

deploy/addons/registry-aliases/README.md

+# Minikube Registry Aliases Addon
+
+An addon to minikube that can help push and pull from the minikube registry using custom domain names. The custom domain names will be made resolveable from with in cluster and at minikube node.
+
+## How to use ?
+
+### Start minikube
+
+```shell
+minikube start -p demo
+```
+This addon depends on `registry` addon, it need to be enabled before the alias addon is installed:
+
+### Enable internal registry
+
+```shell
+minikube addons enable registry
+```
+
+Verifying the registry deployment
+
+```shell
+watch kubectl get pods -n kube-system
+```
+
+```shell
+NAME                           READY   STATUS    RESTARTS   AGE
+coredns-6955765f44-kpbzt       1/1     Running   0          16m
+coredns-6955765f44-lzlsv       1/1     Running   0          16m
+etcd-demo                      1/1     Running   0          16m
+kube-apiserver-demo            1/1     Running   0          16m
+kube-controller-manager-demo   1/1     Running   0          16m
+kube-proxy-q8rb9               1/1     Running   0          16m
+kube-scheduler-demo            1/1     Running   0          16m
+*registry-4k8zs*              1/1     Running   0          40s
+registry-proxy-vs8jt           1/1     Running   0          40s
+storage-provisioner            1/1     Running   0          16m
+```
+
+```shell
+kubectl get svc -n kube-system
+```
+
+```shell
+NAME       TYPE        CLUSTER-IP     EXTERNAL-IP   PORT(S)                  AGE
+kube-dns   ClusterIP   10.96.0.10     <none>        53/UDP,53/TCP,9153/TCP   17m
+registry   ClusterIP   10.97.247.75   <none>        80/TCP                   94s
+```
+
+>
+> **NOTE:**
+> Please make a note of the CLUSTER-IP of `registry` service
+
+### Enable registry aliases addon
+
+```shell
+minikube addons enable registry-aliases
+🌟  The 'registry-aliases' addon is enabled
+```
+
+You can check the mikikube vm's `/etc/hosts` file for the registry aliases entries:
+
+```shell
+watch minikube ssh -- cat /etc/hosts
+```
+
+```shell
+127.0.0.1       localhost
+127.0.1.1 demo
+10.97.247.75    example.org
+10.97.247.75    example.com
+10.97.247.75    test.com
+10.97.247.75    test.org
+```
+
+The above output shows that the Daemonset has added the `registryAliases` from the ConfigMap pointing to the internal registry's __CLUSTER-IP__.
+
+### Update CoreDNS
+
+The coreDNS would have been automatically updated by the patch-coredns. A successful job run will have coredns ConfigMap updated like:
+
+```yaml
+apiVersion: v1
+data:
+  Corefile: |-
+    .:53 {
+        errors
+        health
+        rewrite name example.com registry.kube-system.svc.cluster.local
+        rewrite name example.org registry.kube-system.svc.cluster.local
+        rewrite name test.com registry.kube-system.svc.cluster.local
+        rewrite name test.org registry.kube-system.svc.cluster.local
+        kubernetes cluster.local in-addr.arpa ip6.arpa {
+           pods insecure
+           upstream
+           fallthrough in-addr.arpa ip6.arpa
+        }
+        prometheus :9153
+        proxy . /etc/resolv.conf
+        cache 30
+        loop
+        reload
+        loadbalance
+    }
+kind: ConfigMap
+metadata:
+  name: coredns
+```
+
+To verify it run the following command:
+
+```shell
+kubectl get cm -n kube-system coredns -o yaml
+```
+
+Once you have successfully patched you can now push and pull from the registry using suffix `example.com`, `example.org`,`test.com` and `test.org`.
+
+The successful run will show the following extra pods (Daemonset, Job) in `kube-system` namespace:
+
+```shell
+NAME                                    READY   STATUS      RESTARTS   AGE
+registry-aliases-hosts-update-995vx     1/1     Running     0          47s
+registry-aliases-patch-core-dns-zsxfc   0/1     Completed   0          47s
+```
+
+## Verify with sample application
+
+You can verify the deployment end to end using the example [application](https://github.com/kameshsampath/minikube-registry-aliases-demo).
+
+```shell
+git clone https://github.com/kameshsampath/minikube-registry-aliases-demo
+cd minikube-registry-aliases-demo
+```
+
+Make sure you set the docker context using `eval $(minikube -p demo docker-env)`
+
+Deploy the application using [Skaffold](https://skaffold.dev):
+
+```shell
+skaffold dev --port-forward
+```
+
+Once the application is running try doing `curl localhost:8080` to see the `Hello World` response
+
+You can also update [skaffold.yaml](./skaffold.yaml) and [app.yaml](.k8s/app.yaml), to use `test.org`, `test.com` or `example.org` as container registry urls, and see all the container image names resolves to internal registry, resulting in successful build and deployment.
+
+> **NOTE**:
+>
+> You can also update [skaffold.yaml](./skaffold.yaml) and [app. yaml](.k8s/app.yaml), to use `test.org`, `test.com` or > `example.org` as container registry urls, and see all the > container image names resolves to internal registry, resulting in successful build and deployment.

deploy/addons/registry-aliases/node-etc-hosts-update.tmpl

+apiVersion: apps/v1
+kind: DaemonSet
+metadata:
+  name: registry-aliases-hosts-update
+  namespace: kube-system
+  labels:
+    kubernetes.io/minikube-addons: registry-aliases
+    addonmanager.kubernetes.io/mode: Reconcile
+spec:
+  selector:
+    matchLabels:
+      app: registry-aliases-hosts-update
+  template:
+    metadata:
+      labels:
+        app: registry-aliases-hosts-update
+    spec:
+      initContainers:
+        - name: update
+          image: registry.fedoraproject.org/fedora
+          volumeMounts:
+            - name: etchosts
+              mountPath: /host-etc/hosts
+              readOnly: false
+          env:
+            - name: REGISTRY_ALIASES
+              valueFrom:
+                configMapKeyRef:
+                  name: registry-aliases
+                  key: registryAliases
+          command:
+            - bash
+            - -ce
+            - |
+              NL=$'\n'
+              TAB=$'\t'
+              HOSTS="$(cat /host-etc/hosts)"
+              [ -z "$REGISTRY_SERVICE_HOST" ] && echo "Failed to get hosts entry for default registry" && exit 1;
+              for H in $REGISTRY_ALIASES; do                
+                echo "$HOSTS" | grep "$H"  || HOSTS="$HOSTS$NL$REGISTRY_SERVICE_HOST$TAB$H";
+              done;
+              echo "$HOSTS" | diff -u /host-etc/hosts - || echo "$HOSTS" > /host-etc/hosts
+              echo "Done."
+      containers:
+        - name: pause-for-update
+          image: gcr.io/google_containers/pause-amd64:3.1
+      terminationGracePeriodSeconds: 30
+      volumes:
+        - name: etchosts
+          hostPath:
+            path: /etc/hosts

deploy/addons/registry-aliases/patch-coredns-job.tmpl

+---
+apiVersion: batch/v1
+kind: Job
+metadata:
+  name: registry-aliases-patch-core-dns
+  namespace: kube-system
+spec:
+  ttlSecondsAfterFinished: 100
+  template:
+    spec:
+      serviceAccountName: registry-aliases-sa
+      volumes:
+       - name: minikube
+         hostPath: 
+           path: /var/lib/minikube/binaries
+      containers:
+       - name: core-dns-patcher
+         image:  quay.io/rhdevelopers/core-dns-patcher
+         imagePullPolicy: IfNotPresent
+         # using the kubectl from the minikube instance
+         volumeMounts:
+           - mountPath: /var/lib/minikube/binaries
+             name: minikube
+             readOnly: true
+      restartPolicy: Never
+  backoffLimit: 4
\ No newline at end of file

deploy/addons/registry-aliases/registry-aliases-config.tmpl

+apiVersion: v1
+kind: ConfigMap
+metadata:
+  name: registry-aliases
+  namespace: kube-system
+  labels:
+    kubernetes.io/minikube-addons: registry-aliases
+    addonmanager.kubernetes.io/mode: Reconcile
+data:
+  # Add additonal hosts seperated by new-line
+  registryAliases: >-
+    example.org
+    example.com
+    test.com
+    test.org
+  # default registry address in minikube when enabled via minikube addons enable registry
+  registrySvc: registry.kube-system.svc.cluster.local
+

deploy/addons/registry-aliases/registry-aliases-sa-crb.tmpl

+apiVersion: rbac.authorization.k8s.io/v1
+kind: ClusterRoleBinding
+metadata:
+  name: registry-aliases-crb
+subjects:
+- kind: ServiceAccount
+  name: registry-aliases-sa
+  namespace: kube-system
+roleRef:
+  kind: ClusterRole
+  name: cluster-admin
+  apiGroup: rbac.authorization.k8s.io
\ No newline at end of file

deploy/addons/registry-aliases/registry-aliases-sa.tmpl

+apiVersion: v1
+kind: ServiceAccount
+metadata:
+   name: registry-aliases-sa
+   namespace: kube-system
\ No newline at end of file

pkg/addons/config.go

@@ -112,6 +112,13 @@ var Addons = []*Addon{
 		set:       SetBool,
 		callbacks: []setFn{enableOrDisableAddon},
 	},
+	{
+		name:      "registry-aliases",
+		set:       SetBool,
+		callbacks: []setFn{enableOrDisableAddon},
+		//TODO - add other settings
+		//TODO check if registry addon is enabled
+	},
 	{
 		name:      "storage-provisioner",
 		set:       SetBool,

pkg/minikube/assets/addons.go

@@ -246,6 +246,38 @@ var Addons = map[string]*Addon{
 			"0640",
 			false),
 	}, false, "registry-creds"),
+	"registry-aliases": NewAddon([]*BinAsset{
+		MustBinAsset(
+			"deploy/addons/registry-aliases/registry-aliases-sa.tmpl",
+			vmpath.GuestAddonsDir,
+			"registry-aliases-sa.yaml",
+			"0640",
+			false),
+		MustBinAsset(
+			"deploy/addons/registry-aliases/registry-aliases-sa-crb.tmpl",
+			vmpath.GuestAddonsDir,
+			"registry-aliases-sa-crb.yaml",
+			"0640",
+			false),
+		MustBinAsset(
+			"deploy/addons/registry-aliases/registry-aliases-config.tmpl",
+			vmpath.GuestAddonsDir,
+			"registry-aliases-config.yaml",
+			"0640",
+			false),
+		MustBinAsset(
+			"deploy/addons/registry-aliases/node-etc-hosts-update.tmpl",
+			vmpath.GuestAddonsDir,
+			"node-etc-hosts-update.yaml",
+			"0640",
+			false),
+		MustBinAsset(
+			"deploy/addons/registry-aliases/patch-coredns-job.tmpl",
+			vmpath.GuestAddonsDir,
+			"patch-coredns-job.yaml",
+			"0640",
+			false),
+	}, false, "registry-aliases"),
 	"freshpod": NewAddon([]*BinAsset{
 		MustBinAsset(
 			"deploy/addons/freshpod/freshpod-rc.yaml.tmpl",