Getting started with Kubernetes Operators in Go

In the past few weeks I started to learn Go and beginners like me can make quick progress once you understand the structure and some basics about the programming language. I felt that from all the learning and reading I’ve done on Go and Kubernetes operators, I had enough knowledge to start writing my own Kubernetes operator in Go.

At the beginning of last year, RedHat released the operator-sdk which helps to create the scaffolding for writing your own operators in Ansible, Helm or natively in Go. There has been quite a few changes along the way around the operator-sdk and it is maturing a lot over the course of the past year.

The instructions on how to install Go can be found on the Go website and we need the latest version of the operator-sdk:

$ wget https://github.com/operator-framework/operator-sdk/releases/download/v1.2.0/operator-sdk-v1.2.0-x86_64-linux-gnu
$ mv operator-sdk-v1.2.0-x86_64-linux-gnu operator-sdk
$ sudo mv operator-sdk /usr/local/bin/

Create a new folder and start to initialise the project. You see that I have already set the option --domain so all API groups will be <-group->.helloworld.io. The --repo option allows me to create the project folder outside of my $GOPATH environment. Infos about the folder structure you can find in the Kubebuilder documentation:

$ mkdir k8s-helloworld-operator
$ cd k8s-helloworld-operator
$ operator-sdk init --domain=helloworld.io --repo=github.com/berndonline/k8s-helloworld-operator

The last thing we need before we start writing the operator is to create a new API and Controller and this will scaffold the operator API at api/v1alpha1/operator_types.go and the controller at controllers/operator_controller.go.

$ operator-sdk create api --group app --version v1alpha1 --kind Operator
Create Resource [y/n]
y
Create Controller [y/n]
y
Writing scaffold for you to edit...
api/v1alpha1/operator_types.go
controllers/operator_controller.go
...
  • Define your API

Define your API for the operator custom resource by editing the Go type definitions at api/v1alpha1/operator_types.go

// OperatorSpec defines the desired state of Operator
type OperatorSpec struct {
	// INSERT ADDITIONAL SPEC FIELDS - desired state of cluster
	// Important: Run "make" to regenerate code after modifying this file

	// Foo is an example field of Operator. Edit Operator_types.go to remove/update
	Size     int32  `json:"size"`
	Image    string `json:"image"`
	Response string `json:"response"`
}
// OperatorStatus defines the observed state of Operator
type OperatorStatus struct {
	// INSERT ADDITIONAL STATUS FIELD - define observed state of cluster
	// Important: Run "make" to regenerate code after modifying this file
	Nodes []string `json:"nodes"`
}

// Operator is the Schema for the operators API
// +kubebuilder:subresource:status
type Operator struct {
	metav1.TypeMeta   `json:",inline"`
	metav1.ObjectMeta `json:"metadata,omitempty"`

	Spec   OperatorSpec   `json:"spec,omitempty"`
	Status OperatorStatus `json:"status,omitempty"`
}

After modifying the _types.go file you always need to run the following command to update the generated code for that resource type:

$ make generate 
/home/ubuntu/.go/bin/controller-gen object:headerFile="hack/boilerplate.go.txt" paths="./..."
  • Generate Custom Resource Definition (CRD) manifests

In the previous step we defined the API with spec and status fields of the CRD manifests, which can be generated and updated with the following command:

$ make manifests
/home/ubuntu/.go/bin/controller-gen "crd:trivialVersions=true" rbac:roleName=manager-role webhook paths="./..." output:crd:artifacts:config=config/crd/bases

This makefile will invoke the controller-gen to generate the CRD manifests at config/crd/bases/app.helloworld.io_operators.yaml and below you see my custom resource example for the operator:

apiVersion: app.helloworld.io/v1alpha1
kind: Operator
metadata:
  name: operator-sample
spec:
  size: 1
  response: "Hello, World!"
  image: "ghcr.io/berndonline/k8s/go-helloworld:latest"
  • Controller

In the beginning when I created the API, the operator-sdk automatically created the controller file for me at controllers/operator_controller.go which we now start to modify and add the Go code. I will not go into every detail because the different resources you will create will all look very similar and repeat like you will see in example code. I will mainly focus on the Deployment for my Helloworld container image which I want to deploy using the operator.

Let’s start looking at the deploymentForOperator function which defines and returns the Kubernetes Deployment object. You see there that I invoke an imported Go packages like &appsv1.Deployment and the import is defined at the top of the controller file. You can find details about this in the Go Doc reference: godoc.org/k8s.io/api/apps/v1

// deploymentForOperator returns a operator Deployment object
func (r *OperatorReconciler) deploymentForOperator(m *appv1alpha1.Operator) *appsv1.Deployment {
	ls := labelsForOperator(m.Name)
	replicas := m.Spec.Size

	dep := &appsv1.Deployment{
		ObjectMeta: metav1.ObjectMeta{
			Name:      m.Name,
			Namespace: m.Namespace,
		},
		Spec: appsv1.DeploymentSpec{
			Replicas: &replicas,
			Selector: &metav1.LabelSelector{
				MatchLabels: ls,
			},
			Template: corev1.PodTemplateSpec{
				ObjectMeta: metav1.ObjectMeta{
					Labels: ls,
				},
				Spec: corev1.PodSpec{
					Containers: []corev1.Container{{
						Image:           m.Spec.Image,
						ImagePullPolicy: "Always",
						Name:            "helloworld",
						Ports: []corev1.ContainerPort{{
							ContainerPort: 8080,
							Name:          "operator",
						}},
						Env: []corev1.EnvVar{{
							Name:  "RESPONSE",
							Value: m.Spec.Response,
						}},
						EnvFrom: []corev1.EnvFromSource{{
							ConfigMapRef: &corev1.ConfigMapEnvSource{
								LocalObjectReference: corev1.LocalObjectReference{
									Name: m.Name,
								},
							},
						}},
						VolumeMounts: []corev1.VolumeMount{{
							Name:      m.Name,
							ReadOnly:  true,
							MountPath: "/helloworld/",
						}},
					}},
					Volumes: []corev1.Volume{{
						Name: m.Name,
						VolumeSource: corev1.VolumeSource{
							ConfigMap: &corev1.ConfigMapVolumeSource{
								LocalObjectReference: corev1.LocalObjectReference{
									Name: m.Name,
								},
							},
						},
					}},
				},
			},
		},
	}

	// Set Operator instance as the owner and controller
	ctrl.SetControllerReference(m, dep, r.Scheme)
	return dep
}

We have defined the deploymentForOperator function and now we can look into the Reconcile function and add the step to check if the deployment already exists and, if not, to create the new deployment:

// Check if the deployment already exists, if not create a new one
found := &appsv1.Deployment{}
err = r.Get(ctx, types.NamespacedName{Name: operator.Name, Namespace: operator.Namespace}, found)
if err != nil && errors.IsNotFound(err) {
	// Define a new deployment
	dep := r.deploymentForOperator(operator)
	log.Info("Creating a new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
	err = r.Create(ctx, dep)
	if err != nil {
		log.Error(err, "Failed to create new Deployment", "Deployment.Namespace", dep.Namespace, "Deployment.Name", dep.Name)
		return ctrl.Result{}, err
	}
	// Deployment created successfully - return and requeue
	return ctrl.Result{Requeue: true}, nil
} else if err != nil {
	log.Error(err, "Failed to get Deployment")
	return ctrl.Result{}, err
}

Unfortunately this isn’t enough because this will only check if the deployment exists or not and create a new deployment, but it will not update the deployment if the custom resource is changed.

We need to add two more steps to check if the created Deployment Spec.Template matches the Spec.Template from the  deploymentForOperator function and the Deployment Spec.Replicas the defined size from the custom resource. I will make use of the defined variable found := &appsv1.Deployment{} from the previous step when I checked if the deployment exists.

// Check if the deployment Spec.Template, matches the found Spec.Template
deploy := r.deploymentForOperator(operator)
if !equality.Semantic.DeepDerivative(deploy.Spec.Template, found.Spec.Template) {
	found = deploy
	log.Info("Updating Deployment", "Deployment.Namespace", found.Namespace, "Deployment.Name", found.Name)
	err := r.Update(ctx, found)
	if err != nil {
		log.Error(err, "Failed to update Deployment", "Deployment.Namespace", found.Namespace, "Deployment.Name", found.Name)
		return ctrl.Result{}, err
	}
	return ctrl.Result{Requeue: true}, nil
}

// Ensure the deployment size is the same as the spec
size := operator.Spec.Size
if *found.Spec.Replicas != size {
	found.Spec.Replicas = &size
	err = r.Update(ctx, found)
	if err != nil {
		log.Error(err, "Failed to update Deployment", "Deployment.Namespace", found.Namespace, "Deployment.Name", found.Name)
		return ctrl.Result{}, err
	}
	// Spec updated - return and requeue
	return ctrl.Result{Requeue: true}, nil
}

The SetupWithManager() function in controllers/operator_controller.go specifies how the controller is built to watch a custom resource and other resources that are owned and managed by that controller.

func (r *OperatorReconciler) SetupWithManager(mgr ctrl.Manager) error {
	return ctrl.NewControllerManagedBy(mgr).
		For(&appv1alpha1.Operator{}).
		Owns(&appsv1.Deployment{}).
		Owns(&corev1.ConfigMap{}).
		Owns(&corev1.Service{}).
		Owns(&networkingv1beta1.Ingress{}).
		Complete(r)
}

Basically that’s all I need to write for the controller to deploy my Helloworld container image using an Kubernetes operator. In my code example you will find that I also create a Kubernetes Service, Ingress and ConfigMap but you see that this mostly repeats what I have done with the Deployment object.

  • RBAC permissions

Before we can start running the operator, we need to define the RBAC permissions the controller needs to interact with the resources it manages otherwise your controller will not work. These are specified via [RBAC markers] like these:

// +kubebuilder:rbac:groups=app.helloworld.io,resources=operators,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=app.helloworld.io,resources=operators/status,verbs=get;update;patch
// +kubebuilder:rbac:groups=app.helloworld.io,resources=operators/finalizers,verbs=update
// +kubebuilder:rbac:groups=apps,resources=deployments,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=core,resources=services,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=core,resources=configmaps,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=networking.k8s.io,resources=ingresses,verbs=get;list;watch;create;update;patch;delete
// +kubebuilder:rbac:groups=core,resources=pods,verbs=get;list;watch

The ClusterRole manifest at config/rbac/role.yaml is generated from the above markers via controller-gen with the following command:

$ make manifests 
/home/ubuntu/.go/bin/controller-gen "crd:trivialVersions=true" rbac:roleName=manager-role webhook paths="./..." output:crd:artifacts:config=config/crd/bases
  • Running the Operator

We need a Kubernetes cluster and admin privileges to run the operator. I will use Kind which will run a lightweight Kubernetes cluster in your local Docker engine, which is all I need to run and test my Helloworld operator:

$ ./scripts/create-kind-cluster.sh 
Creating cluster "kind" ...
 ✓ Ensuring node image (kindest/node:v1.19.1) 🖼 
 ✓ Preparing nodes 📦  
 ✓ Writing configuration 📜 
 ✓ Starting control-plane 🕹️ 
 ✓ Installing CNI 🔌 
 ✓ Installing StorageClass 💾 
Set kubectl context to "kind-kind"
You can now use your cluster with:

kubectl cluster-info --context kind-kind

Have a question, bug, or feature request? Let us know! https://kind.sigs.k8s.io/#community 🙂

Before running the operator the custom resource Definition must be registered with the Kubernetes apiserver:

$ make install
/home/ubuntu/.go/bin/controller-gen "crd:trivialVersions=true" rbac:roleName=manager-role webhook paths="./..." output:crd:artifacts:config=config/crd/bases
/usr/bin/kustomize build config/crd | kubectl apply -f -
Warning: apiextensions.k8s.io/v1beta1 CustomResourceDefinition is deprecated in v1.16+, unavailable in v1.22+; use apiextensions.k8s.io/v1 CustomResourceDefinition
customresourcedefinition.apiextensions.k8s.io/operators.app.helloworld.io created

We can now run the operator locally on my workstation:

$ make run
/home/ubuntu/.go/bin/controller-gen object:headerFile="hack/boilerplate.go.txt" paths="./..."
go fmt ./...
go vet ./...
/home/ubuntu/.go/bin/controller-gen "crd:trivialVersions=true" rbac:roleName=manager-role webhook paths="./..." output:crd:artifacts:config=config/crd/bases
go run ./main.go
2020-11-22T18:12:49.023Z	INFO	controller-runtime.metrics	metrics server is starting to listen	{"addr": ":8080"}
2020-11-22T18:12:49.024Z	INFO	setup	starting manager
2020-11-22T18:12:49.025Z	INFO	controller-runtime.manager	starting metrics server	{"path": "/metrics"}
2020-11-22T18:12:49.025Z	INFO	controller	Starting EventSource	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "source": "kind source: /, Kind="}
2020-11-22T18:12:49.126Z	INFO	controller	Starting EventSource	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "source": "kind source: /, Kind="}
2020-11-22T18:12:49.226Z	INFO	controller	Starting EventSource	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "source": "kind source: /, Kind="}
2020-11-22T18:12:49.327Z	INFO	controller	Starting EventSource	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "source": "kind source: /, Kind="}
2020-11-22T18:12:49.428Z	INFO	controller	Starting EventSource	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "source": "kind source: /, Kind="}
2020-11-22T18:12:49.528Z	INFO	controller	Starting Controller	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator"}
2020-11-22T18:12:49.528Z	INFO	controller	Starting workers	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "worker count": 1}

Let’s open a new terminal and apply the custom resource example:

$ kubectl apply -f config/samples/app_v1alpha1_operator.yaml 
operator.app.helloworld.io/operator-sample created

Going back to the terminal where the operator is running, you see the log messages that it invoke the different functions to deploy the defined resource objects:

2020-11-22T18:15:30.412Z	INFO	controllers.Operator	Creating a new Deployment	{"operator": "default/operator-sample", "Deployment.Namespace": "default", "Deployment.Name": "operator-sample"}
2020-11-22T18:15:30.446Z	INFO	controllers.Operator	Creating a new ConfigMap	{"operator": "default/operator-sample", "ConfigMap.Namespace": "default", "ConfigMap.Name": "operator-sample"}
2020-11-22T18:15:30.453Z	INFO	controllers.Operator	Creating a new Service	{"operator": "default/operator-sample", "Service.Namespace": "default", "Service.Name": "operator-sample"}
2020-11-22T18:15:30.470Z	INFO	controllers.Operator	Creating a new Ingress	{"operator": "default/operator-sample", "Ingress.Namespace": "default", "Ingress.Name": "operator-sample"}
2020-11-22T18:15:30.927Z	DEBUG	controller	Successfully Reconciled	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "name": "operator-sample", "namespace": "default"}
2020-11-22T18:15:30.927Z	DEBUG	controller	Successfully Reconciled	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "name": "operator-sample", "namespace": "default"}
2020-11-22T18:15:33.776Z	DEBUG	controller	Successfully Reconciled	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "name": "operator-sample", "namespace": "default"}
2020-11-22T18:15:35.181Z	DEBUG	controller	Successfully Reconciled	{"reconcilerGroup": "app.helloworld.io", "reconcilerKind": "Operator", "controller": "operator", "name": "operator-sample", "namespace": "default"}

In the default namespace where I applied the custom resource you will see the deployed resources by the operator:

$ kubectl get operators.app.helloworld.io 
NAME              AGE
operator-sample   6m11s
$ kubectl get all
NAME                                   READY   STATUS    RESTARTS   AGE
pod/operator-sample-767897c4b9-8zwsd   1/1     Running   0          2m59s

NAME                      TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)    AGE
service/kubernetes        ClusterIP   10.96.0.1               443/TCP    29m
service/operator-sample   ClusterIP   10.96.199.188           8080/TCP   2m59s

NAME                              READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/operator-sample   1/1     1            1           2m59s

NAME                                         DESIRED   CURRENT   READY   AGE
replicaset.apps/operator-sample-767897c4b9   1         1         1       2m59s

There is not much else to do other than to build the operator image and push to an image registry so that I can run the operator on a Kubernetes cluster.

$ make docker-build IMG=ghcr.io/berndonline/k8s/helloworld-operator:latest
$ make docker-push IMG=ghcr.io/berndonline/k8s/helloworld-operator:latest
$ kustomize build config/default | kubectl apply -f -

I hope this article is useful for getting you started on writing your own Kubernetes operator in Go.

Getting started with OpenShift Hive

If you don’t know OpenShift Hive I recommend having a look at the video of my talk at RedHat OpenShift Commons about OpenShift Hive where I also talk about how you can provision and manage the lifecycle of OpenShift 4 clusters using the Kubernetes API and the OpenShift Hive operator.

The Hive operator has three main components the admission controller,  the Hive controller and the Hive operator itself. For more information about the Hive architecture visit the Hive docs:

You can use an OpenShift or native Kubernetes cluster to run the operator, in my case I use a EKS cluster. Let’s go through the prerequisites which are required to generate the manifests and the hiveutil:

$ curl -s "https://raw.githubusercontent.com/\
> kubernetes-sigs/kustomize/master/hack/install_kustomize.sh"  | bash
$ sudo mv ./kustomize /usr/bin/
$ wget https://dl.google.com/go/go1.13.3.linux-amd64.tar.gz
$ tar -xvf go1.13.3.linux-amd64.tar.gz
$ sudo mv go /usr/local

To setup the Go environment copy the content below and add to your .profile:

export GOPATH="${HOME}/.go"
export PATH="$PATH:/usr/local/go/bin"
export PATH="$PATH:${GOPATH}/bin:${GOROOT}/bin"

Continue with installing the Go dependencies and clone the OpenShift Hive Github repository:

$ mkdir -p ~/.go/src/github.com/openshift/
$ go get github.com/golang/mock/mockgen
$ go get github.com/golang/mock/gomock
$ go get github.com/cloudflare/cfssl/cmd/cfssl
$ go get github.com/cloudflare/cfssl/cmd/cfssljson
$ cd ~/.go/src/github.com/openshift/
$ git clone https://github.com/openshift/hive.git
$ cd hive/
$ git checkout remotes/origin/master

Before we run make deploy I would recommend modifying the Makefile that we only generate the Hive manifests without deploying them to Kubernetes:

$ sed -i -e 's#oc apply -f config/crds# #' -e 's#kustomize build overlays/deploy | oc apply -f -#kustomize build overlays/deploy > hive.yaml#' Makefile
$ make deploy
# The apis-path is explicitly specified so that CRDs are not created for v1alpha1
go run tools/vendor/sigs.k8s.io/controller-tools/cmd/controller-gen/main.go crd --apis-path=pkg/apis/hive/v1
CRD files generated, files can be found under path /home/ubuntu/.go/src/github.com/openshift/hive/config/crds.
go generate ./pkg/... ./cmd/...
hack/update-bindata.sh
# Deploy the operator manifests:
mkdir -p overlays/deploy
cp overlays/template/kustomization.yaml overlays/deploy
cd overlays/deploy && kustomize edit set image registry.svc.ci.openshift.org/openshift/hive-v4.0:hive=registry.svc.ci.openshift.org/openshift/hivev1:hive
kustomize build overlays/deploy > hive.yaml
rm -rf overlays/deploy

Quick look at the content of the hive.yaml manifest:

$ cat hive.yaml
apiVersion: v1
kind: Namespace
metadata:
  name: hive
---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: hive-operator
  namespace: hive

...

---
apiVersion: apps/v1
kind: Deployment
metadata:
  labels:
    control-plane: hive-operator
    controller-tools.k8s.io: "1.0"
  name: hive-operator
  namespace: hive
spec:
  replicas: 1
  revisionHistoryLimit: 4
  selector:
    matchLabels:
      control-plane: hive-operator
      controller-tools.k8s.io: "1.0"
  template:
    metadata:
      labels:
        control-plane: hive-operator
        controller-tools.k8s.io: "1.0"
    spec:
      containers:
      - command:
        - /opt/services/hive-operator
        - --log-level
        - info
        env:
        - name: CLI_CACHE_DIR
          value: /var/cache/kubectl
        image: registry.svc.ci.openshift.org/openshift/hive-v4.0:hive
        imagePullPolicy: Always
        livenessProbe:
          failureThreshold: 1
          httpGet:
            path: /debug/health
            port: 8080
          initialDelaySeconds: 10
          periodSeconds: 10
        name: hive-operator
        resources:
          requests:
            cpu: 100m
            memory: 256Mi
        volumeMounts:
        - mountPath: /var/cache/kubectl
          name: kubectl-cache
      serviceAccountName: hive-operator
      terminationGracePeriodSeconds: 10
      volumes:
      - emptyDir: {}
        name: kubectl-cache

Now we can apply the Hive custom resource definition (crds):

$ kubectl apply -f ./config/crds/
customresourcedefinition.apiextensions.k8s.io/checkpoints.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterdeployments.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterdeprovisions.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterimagesets.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterprovisions.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/clusterstates.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/dnszones.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/hiveconfigs.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/machinepools.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/selectorsyncidentityproviders.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/selectorsyncsets.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/syncidentityproviders.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/syncsets.hive.openshift.io created
customresourcedefinition.apiextensions.k8s.io/syncsetinstances.hive.openshift.io created

And continue to apply the hive.yaml manifest for deploying the OpenShift Hive operator and its components:

$ kubectl apply -f hive.yaml
namespace/hive created
serviceaccount/hive-operator created
clusterrole.rbac.authorization.k8s.io/hive-frontend created
clusterrole.rbac.authorization.k8s.io/hive-operator-role created
clusterrole.rbac.authorization.k8s.io/manager-role created
clusterrole.rbac.authorization.k8s.io/system:openshift:hive:hiveadmission created
rolebinding.rbac.authorization.k8s.io/extension-server-authentication-reader-hiveadmission created
clusterrolebinding.rbac.authorization.k8s.io/auth-delegator-hiveadmission created
clusterrolebinding.rbac.authorization.k8s.io/hive-frontend created
clusterrolebinding.rbac.authorization.k8s.io/hive-operator-rolebinding created
clusterrolebinding.rbac.authorization.k8s.io/hiveadmission-hive-hiveadmission created
clusterrolebinding.rbac.authorization.k8s.io/hiveapi-cluster-admin created
clusterrolebinding.rbac.authorization.k8s.io/manager-rolebinding created
deployment.apps/hive-operator created

For the Hive admission controller you need to generate a SSL certifcate:

$ ./hack/hiveadmission-dev-cert.sh
~/Dropbox/hive/hiveadmission-certs ~/Dropbox/hive
2020/02/03 22:17:30 [INFO] generate received request
2020/02/03 22:17:30 [INFO] received CSR
2020/02/03 22:17:30 [INFO] generating key: ecdsa-256
2020/02/03 22:17:30 [INFO] encoded CSR
certificatesigningrequest.certificates.k8s.io/hiveadmission.hive configured
certificatesigningrequest.certificates.k8s.io/hiveadmission.hive approved
-----BEGIN CERTIFICATE-----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-----END CERTIFICATE-----
secret/hiveadmission-serving-cert created
~/Dropbox/hive

Afterwards we can check if all the pods are running, this might take a few seconds:

$ kubectl get pods -n hive
NAME                                READY   STATUS    RESTARTS   AGE
hive-controllers-7c6ccc84b9-q7k7m   1/1     Running   0          31s
hive-operator-f9f4447fd-jbmkh       1/1     Running   0          55s
hiveadmission-6766c5bc6f-9667g      1/1     Running   0          27s
hiveadmission-6766c5bc6f-gvvlq      1/1     Running   0          27s

The Hive operator is successfully installed on your Kubernetes cluster but we are not finished yet. To create the required Cluster Deployment manifests we need to generate the hiveutil binary:

$ make hiveutil
go generate ./pkg/... ./cmd/...
hack/update-bindata.sh
go build -o bin/hiveutil github.com/openshift/hive/contrib/cmd/hiveutil

To generate Hive Cluster Deployment manifests just run the following hiveutil command below, I output the definition with -o into yaml:

$ bin/hiveutil create-cluster --base-domain=mydomain.example.com --cloud=aws mycluster -o yaml
apiVersion: v1
items:
- apiVersion: hive.openshift.io/v1
  kind: ClusterImageSet
  metadata:
    creationTimestamp: null
    name: mycluster-imageset
  spec:
    releaseImage: quay.io/openshift-release-dev/ocp-release:4.3.2-x86_64
  status: {}
- apiVersion: v1
  kind: Secret
  metadata:
    creationTimestamp: null
    name: mycluster-aws-creds
  stringData:
    aws_access_key_id: <-YOUR-AWS-ACCESS-KEY->
    aws_secret_access_key: <-YOUR-AWS-SECRET-KEY->
  type: Opaque
- apiVersion: v1
  data:
    install-config.yaml: <-BASE64-ENCODED-OPENSHIFT4-INSTALL-CONFIG->
  kind: Secret
  metadata:
    creationTimestamp: null
    name: mycluster-install-config
  type: Opaque
- apiVersion: hive.openshift.io/v1
  kind: ClusterDeployment
  metadata:
    creationTimestamp: null
    name: mycluster
  spec:
    baseDomain: mydomain.example.com
    clusterName: mycluster
    controlPlaneConfig:
      servingCertificates: {}
    installed: false
    platform:
      aws:
        credentialsSecretRef:
          name: mycluster-aws-creds
        region: us-east-1
    provisioning:
      imageSetRef:
        name: mycluster-imageset
      installConfigSecretRef:
        name: mycluster-install-config
  status:
    clusterVersionStatus:
      availableUpdates: null
      desired:
        force: false
        image: ""
        version: ""
      observedGeneration: 0
      versionHash: ""
- apiVersion: hive.openshift.io/v1
  kind: MachinePool
  metadata:
    creationTimestamp: null
    name: mycluster-worker
  spec:
    clusterDeploymentRef:
      name: mycluster
    name: worker
    platform:
      aws:
        rootVolume:
          iops: 100
          size: 22
          type: gp2
        type: m4.xlarge
    replicas: 3
  status:
    replicas: 0
kind: List
metadata: {}

I hope this post is useful in getting you started with OpenShift Hive. In my next article I will go through the details of the OpenShift 4 cluster deployment with Hive.

Read my new article about OpenShift / OKD 4.x Cluster Deployment using OpenShift Hive