atomicturtle / sample-operator

Custom operator based on Operator-sdk

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/shailendra14k/  // remane to your account.
$ cd $GOPATH/src/github.com/shailendra14k/
$ 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=shailendra14k.com/v1alpha1 --kind=Sample

3. Update the Smaple CR Spec and Status at pkg/apis/shailendra14k/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=shailendra14k.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 quay.io/shailendra14k/sample-operator:v0.1 --image-builder podman

//Verify the operator image cretaed locally
[root@shsingh sample-operator]# podman images
REPOSITORY                                                TAG      IMAGE ID       CREATED          SIZE
quay.io/shailendra14k/sample-operator                     v0.1     50fceb91c078   27 seconds ago   150 MB

// Push the image

$ podman push quay.io/shailendra14k/sample-operator:v0.1

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: quay.io/shailendra14k/sample-operator:v0.1
    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/shailendra14k.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-867cf7c68f-jpjxk   1/1       Running   0          95s

NAME                              TYPE        CLUSTER-IP       EXTERNAL-IP   PORT(S)             AGE
service/sample-operator-metrics   ClusterIP   172.30.125.171   <none>        8383/TCP,8686/TCP   76s

NAME                              READY     UP-TO-DATE   AVAILABLE   AGE
deployment.apps/sample-operator   1/1       1            1           97s

NAME                                         DESIRED   CURRENT   READY     AGE
replicaset.apps/sample-operator-867cf7c68f   1         1         1         97s

//Operator logs
{"level":"info","ts":1585146465.5662885,"logger":"metrics","msg":"Metrics Service object created","Service.Name":"sample-operator-metrics","Service.Namespace":"sample-operator"}
{"level":"info","ts":1585146468.5416582,"logger":"cmd","msg":"Starting the Cmd."}
{"level":"info","ts":1585146468.5419788,"logger":"controller-runtime.manager","msg":"starting metrics server","path":"/metrics"}
{"level":"info","ts":1585146468.5421832,"logger":"controller-runtime.controller","msg":"Starting EventSource","controller":"sample-controller","source":"kind source: /, Kind="}
{"level":"info","ts":1585146468.6432557,"logger":"controller-runtime.controller","msg":"Starting EventSource","controller":"sample-controller","source":"kind source: /, Kind="}
{"level":"info","ts":1585146468.743742,"logger":"controller-runtime.controller","msg":"Starting Controller","controller":"sample-controller"}
{"level":"info","ts":1585146468.7437823,"logger":"controller-runtime.controller","msg":"Starting workers","controller":"sample-controller","worker count":1}

5. Create the Sample Custom Resource(CR)

$ cat deploy/crds/shailendra14k.com_v1alpha1_sample_cr.yaml 

apiVersion: shailendra14k.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/shailendra14k.com_v1alpha1_sample_cr.yaml 
sample.shailendra14k.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           4m8s
sample-operator   1/1       1            1           10m

$ oc get pods
NAME                               READY     STATUS    RESTARTS   AGE
example-sample-7d856cb9fc-7pbg2    1/1       Running   0          3m29s
example-sample-7d856cb9fc-bjg47    1/1       Running   0          3m29s
sample-operator-867cf7c68f-jpjxk   1/1       Running   0          10m

$ 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-sampleoperator.apps.lab.com/test
Response received from POD : example-sample-7d856cb9fc-7pbg2

$ curl http://sample-sampleoperator.apps.lab.com/test
Response received from POD : example-sample-7d856cb9fc-bjg47

9. To update the Application size from 2 to 1

apiVersion: shailendra14k.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/shailendra14k.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