binliuk/sample-operator

Sample-operator

Example to create a sample operator using operator-sdk

In this example we will create a sample-operator for deploying sample application based on spring-boot and camel.

Prerequisites.

1. Build the sample App image
2. Install operator-sdk
3. Install golang
4. Access of Openshift cluster with cluster-admin permissions.
5. Openshift CLI(OC)

Steps to create the sample-operator.

1. Create sample-operator project

$ mkdir -p $GOPATH/src/github.com/binliuk/  // remane to your account.
$ cd $GOPATH/src/github.com/binliuk/
$ export GO111MODULE=on
$ operator-sdk new sample-operator
$ cd sample-operator
$ go mod tidy // Install dependencies

2. Verify the directory structure cretaed.

├── build
│   ├── bin
│   │   ├── entrypoint
│   │   └── user_setup
│   └── Dockerfile
├── cmd
│   └── manager
│       └── main.go
├── deploy
│   ├── operator.yaml
│   ├── role_binding.yaml
│   ├── role.yaml
│   └── service_account.yaml
├── go.mod
├── go.sum
├── pkg
│   ├── apis
│   │   └── apis.go
│   └── controller
│       └── controller.go
├── tools.go
└── version
    └── version.go

More info about SDK project layout doc.

2. Create Custom Resource Definition (CRD)

$ operator-sdk add api --api-version=binliuk.com/v1alpha1 --kind=Sample

3. Update the Smaple CR Spec and Status at pkg/apis/binliuk/v1alpha1/sample_types.go

type SampleSpec struct {
  Size        int32             `json:"size"`
  BodyValue   string            `json:"bodyvalue"`
  Image        string           `json:"image"`

}

// SampleStatus defines the observed state of Sample
type SampleStatus struct {
    Nodes []string `json:"nodes"`
}

Run the below command to update the generaed code after modifying *_types.go

$ operator-sdk generate k8s

//Generate the updated CRDs
$ operator-sdk generate crds

4. Create a new Controller to watch and reconcile Sample resource

$ operator-sdk add controller --api-version=binliuk.com/v1alpha1 --kind=Sample

5. Replace the default pkg/controller/sample/sample_controller.go with the sample_controller.go

6. Build and push the Operator image to a reqistry.

$operator-sdk build default-route-openshift-image-registry.apps.osdtest1.h7z8.p2.openshiftapps.com/test/sample-operator:v0.0.1

//Verify the operator image cretaed locally
lbin@lbin-ThinkPad-W530:~/go/src/github.com/binliuk/sample-operator$ docker images
REPOSITORY                                                                                            TAG                 IMAGE ID            CREATED             SIZE
default-route-openshift-image-registry.apps.osdtest1.h7z8.p2.openshiftapps.com/test/sample-operator   v0.0.1              d25097cb8055        About an hour ago   185MB

// Push the image
$ docker login -u `oc whoami` -p `oc whoami -t` default-route-openshift-image-registry.apps.osdtest1.h7z8.p2.openshiftapps.com
$ docker push default-route-openshift-image-registry.apps.osdtest1.h7z8.p2.openshiftapps.com/test/sample-operator

7. Update the default deploy/operator.yaml with the correct image deatils

serviceAccountName: sample-operator
containers:
  - name: sample-operator
    # Replace this with the built image name
    image: image-registry.opernshift-image-registry.svc:5000/test/sample-operator:v0.0.1 
    command:
    - sample-operator
    imagePullPolicy: Always

Steps to deploy the sample-operator on Openshift cluster

1. Create a new project

$ oc new-project sample-operator

2. Create the sample CRD

$ oc create -f deploy/crds/binliuk.com_samples_crd.yaml

3. Deploy the Operator along with set-up the RBAC

$ oc create -f deploy/service_account.yaml
$ oc create -f deploy/role.yaml
$ oc create -f deploy/role_binding.yaml
$ oc create -f deploy/operator.yaml

4. Verify the deployment and logs

$ oc get all
NAME                                  READY   STATUS    RESTARTS   AGE
pod/sample-operator-8f4667bd-zj5d2    1/1     Running   0          47m

NAME                              TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)             AGE
service/sample-operator-metrics   ClusterIP   172.30.82.158   <none>        8383/TCP,8686/TCP   47m

NAME                              READY   UP-TO-DATE   AVAILABLE   AGE
deployment.apps/sample-operator   1/1     1            1           49m

NAME                                         DESIRED   CURRENT   READY   AGE
replicaset.apps/sample-operator-8f4667bd     1         1         1       47m

NAME                                             IMAGE REPOSITORY                                                                                      TAGS     UPDATED
imagestream.image.openshift.io/sample-operator   default-route-openshift-image-registry.apps.osdtest1.h7z8.p2.openshiftapps.com/test/sample-operator   v0.0.1   53 minutes ago

5. Create the Sample Custom Resource(CR)

$ cat deploy/crds/binliuk.com_v1alpha1_sample_cr.yaml 

apiVersion: binliuk.com/v1alpha1
kind: Sample
metadata:
  name: example-sample
spec:
  # Add fields here
  size: 2
  bodyvalue: "Response received from POD : {{env:HOSTNAME}}"
  image: "quay.io/shailendra14k/sample:v0.1"

$ oc create -f deploy/crds/binliuk.com_v1alpha1_sample_cr.yaml 
sample.binliuk.com/example-sample created

6. Verify the application deployemnet and POD has been created.

$ oc get deployment
NAME              READY   UP-TO-DATE   AVAILABLE   AGE
example-sample    2/2     2            2           43m
sample-operator   1/1     1            1           51m

$ oc get pods
NAME                              READY   STATUS    RESTARTS   AGE
example-sample-56d56cdd67-bgrf9   1/1     Running   0          44m
example-sample-56d56cdd67-txlwp   1/1     Running   0          44m
nginx                             1/1     Running   12         12h
sample-operator-8f4667bd-zj5d2    1/1     Running   0          50m

$ oc get samples
NAME             AGE
example-sample   5m23s

7. Create a service and route to test the camel route application(Sample image).

$ oc create service clusterip sample --tcp=8080:8080
$ oc expose svc/sample

8. Test the Application

$ curl http://sample-test.apps.osdtest1.h7z8.p2.openshiftapps.com/test
Response received from POD : example-sample-7d856cb9fc-7pbg2

$ curl http://sample-test.apps.osdtest1.h7z8.p2.openshiftapps.com/test
Response received from POD : example-sample-7d856cb9fc-bjg47

9. To update the Application size from 2 to 1

apiVersion: binliuk.com/v1alpha1
kind: Sample
metadata:
  name: example-sample
spec:
  # Add fields here
  size: 1
  bodyvalue: "Response received from POD : {{env:HOSTNAME}}"
  image: "quay.io/shailendra14k/sample:v0.1"

$ oc apply -f deploy/crds/binliuk.com_v1alpha1_sample_cr.yaml

$ oc get deployment
NAME              READY     UP-TO-DATE   AVAILABLE   AGE
example-sample    1/1       1            1           3m1s

Finally, you can delete the namespace using the command

$ oc delete project sample-operator

Manage the sample-operator using the Operator Lifecycle Manager

#Prerequisites

OLM installed on a Kubernetes-based cluster (v1.8 or above to support the apps/v1beta2 API group), for example OpenShift Container Platform 4.4 Preview OLM enabled

Sample Operator built

#Procedure

1. Generate an Operator manifest

$ operator-sdk generate csv --csv-version 0.0.1

2. Create an OperatorGroup that specifies the namespaces that the Operator will target.

$ cat <<EOF | oc apply -f -
apiVersion: operators.coreos.com/v1
kind: OperatorGroup
metadata:
  name: memcached-operator-group
  namespace: operator-sample
spec:
  targetNamespaces:
  - operator-sample
EOF

3. Deploy the Operator

$ oc create -f deploy/crds/binliuk.com_samples_crd.yaml
$ oc create -f deploy/service_account.yaml
$ oc create -f deploy/role.yaml
$ oc create -f deploy/role_binding.yaml
$ oc apply -f deploy/olm-catalog/sample-operator/0.0.1/sample-operator.v0.0.1.clusterserviceversion.yaml

4. Create an application instance.

$ cat <<EOF | oc apply -f -
apiVersion: binliuk.com/v1alpha1
kind: Sample
metadata:
  name: example-sample
spec:
  # Add fields here
  size: 2
  bodyvalue: "Response received from POD : {{env:HOSTNAME}}"
  image: "quay.io/shailendra14k/sample:v0.1"
EOF

5. Check pods

$ oc get pod
NAME                               READY   STATUS    RESTARTS   AGE
example-sample-7d856cb9fc-c9bl7    1/1     Running   0          13m
example-sample-7d856cb9fc-qj6jw    1/1     Running   0          13m
sample-operator-665fdd6d79-rkzn5   1/1     Running   0          19m
$ oc get sample
NAME             AGE
example-sample   13m