Wordpress-Operator

The Objective of this Operator is to demonstrate Wordpress kind of resource using Kuberentes controller pattern- Operator.Another objective of the repository is to show how to build the custom controller that encapsulates specific domain/application level knowledge. The Operator is built using the operator-sdk framework. If Wordpress and MySQL were to be deployed without operator on Kuberenetes, it can be referred here. Lets understand how can this be achieved via Kubernetes Operator.

Prerequistites

• golang v1.12+.
• set GO111MODULE="on"
• Install the operator-sdk (version 0.15)
• minikube
• kubectl client

Wordpress Resource

The Wordpress Operator using the operator-sdk project deploys wordpress using on sql via a custom resource

• A kubernetes resource of kind: Wordpress and apiVersion: example.com/v1 is created that results in the Operator deploying Deployments, PersistentVolumeClaims, Services, that constitute a simple instance of wordpress on sql.
• The user can specify plaintext password that can be used as a MYSQL_ROOT_PASSWORD. Once the user applies the Wordpress resource (kubectl aply -f ./deploy/crds/example.com_v1_wordpress_cr.yaml) resource, controller could spin up mysql and wordpress pods using the MYSQL_ROOT_PASSWORD as specified in spec.sqlrootpassword. e.g.,

apiVersion: example.com/v1
kind: Wordpress
metadata:
  name: mysite
spec:
  sqlRootPassword: plaintextpassword 

Trying the Operator

git clone https://github.com/priyanka19-98/Wordpress-Operator.git cd Wordpress-Operator We would be trying out the operator locally. By locally we mean that we want to run the operatot logic binary without actually building an image and pushing it to a container registry. Running the operator locally helps in day to day development. You can have a minikube single node local cluster to play with the operator. Before running the operator do:

kubectl apply -f ./deploy/crds/example.com_wordpresses_crd.yaml
kubectl apply -f ./deploy/crds/example.com_v1_wordpress_cr.yaml

The CRD would be registerd and you can check that by the following command: kubectl get crd You should be able to see the output as:

[pjiandan@pjiandan crds]$ kubectl get crd
NAME                      CREATED AT
wordpresses.example.com   2020-09-01T12:29:55Z

After that run the operator locally with operator-sdk run --local, you should see the logs as:

INFO[0000] Running the operator locally in namespace default. 
{"level":"info","ts":1598973876.2819793,"logger":"cmd","msg":"Operator Version: 0.0.1"}
{"level":"info","ts":1598973876.2820053,"logger":"cmd","msg":"Go Version: go1.13.10"}
{"level":"info","ts":1598973876.282011,"logger":"cmd","msg":"Go OS/Arch: linux/amd64"}
{"level":"info","ts":1598973876.2820172,"logger":"cmd","msg":"Version of operator-sdk: v0.15.2"}
{"level":"info","ts":1598973876.285575,"logger":"leader","msg":"Trying to become the leader."}
{"level":"info","ts":1598973876.285611,"logger":"leader","msg":"Skipping leader election; not running in a cluster."}
{"level":"info","ts":1598973876.5921307,"logger":"controller-runtime.metrics","msg":"metrics server is starting to listen","addr":"0.0.0.0:8383"}
{"level":"info","ts":1598973876.596543,"logger":"cmd","msg":"Registering Components."}
{"level":"info","ts":1598973876.5967476,"logger":"cmd","msg":"Skipping CR metrics server creation; not running in a cluster."}
{"level":"info","ts":1598973876.5967603,"logger":"cmd","msg":"Starting the Cmd."}
{"level":"info","ts":1598973876.5973437,"logger":"controller-runtime.controller","msg":"Starting EventSource","controller":"wordpress-controller","source":"kind source: /, Kind="}
{"level":"info","ts":1598973876.5975914,"logger":"controller-runtime.controller","msg":"Starting EventSource","controller":"wordpress-controller","source":"kind source: /, Kind="}
{"level":"info","ts":1598973876.5977812,"logger":"controller-runtime.controller","msg":"Starting EventSource","controller":"wordpress-controller","source":"kind source: /, Kind="}
{"level":"info","ts":1598973876.5979419,"logger":"controller-runtime.controller","msg":"Starting EventSource","controller":"wordpress-controller","source":"kind source: /, Kind="}
{"level":"info","ts":1598973876.5980544,"logger":"controller-runtime.controller","msg":"Starting Controller","controller":"wordpress-controller"}
{"level":"info","ts":1598973876.598183,"logger":"controller-runtime.manager","msg":"starting metrics server","path":"/metrics"}
{"level":"info","ts":1598973876.6982796,"logger":"controller-runtime.controller","msg":"Starting workers","controller":"wordpress-controller","worker count":1}
{"level":"info","ts":1598973876.6983802,"logger":"controller_wordpress","msg":"Reconciling Wordpress","Request.Namespace":"default","Request.Name":"example-wordpress"}
{"level":"info","ts":1598973876.6984997,"logger":"controller_wordpress","msg":"Creating a new PVC","PVC.Namespace":"default","PVC.Name":"wp-pv-claim"}
{"level":"info","ts":1598973876.7138047,"logger":"controller_wordpress","msg":"Creating a new Deployment","Deployment.Namespace":"default","Deployment.Name":"wordpress"}
{"level":"info","ts":1598973876.736821,"logger":"controller_wordpress","msg":"Creating a new Service","Service.Namespace":"default","Service.Name":"wordpress"}
{"level":"info","ts":1598973876.8298655,"logger":"controller_wordpress","msg":"Reconciling Wordpress","Request.Namespace":"default","Request.Name":"example-wordpress"}
{"level":"info","ts":1598973876.8301716,"logger":"controller_wordpress","msg":"Creating a new Service","Service.Namespace":"default","Service.Name":"wordpress"}

This indicates that our operator is up and running.

See if the pods,deployments,pvcs and services are up and running:

kubectl get pods
kubectl get deploy
kubectl get pvc
kubectl get svc

You should be able to see the following output:

[pjiandan@pjiandan crds]$ kubectl get po
NAME                               READY   STATUS    RESTARTS   AGE
wordpress-6d5b4988ff-dcxfj         1/1     Running   0          16h
wordpress-mysql-59d5d89ff8-qj92r   1/1     Running   0          17h
[pjiandan@pjiandan crds]$ kubectl get svc
NAME              TYPE        CLUSTER-IP      EXTERNAL-IP   PORT(S)        AGE
kubernetes        ClusterIP   10.96.0.1       <none>        443/TCP        19h
wordpress         NodePort    10.100.123.86   <none>        80:31881/TCP   16h
wordpress-mysql   ClusterIP   None            <none>        3306/TCP       17h
[pjiandan@pjiandan crds]$ kubectl get deploy
NAME              READY   UP-TO-DATE   AVAILABLE   AGE
wordpress         1/1     1            1           16h
wordpress-mysql   1/1     1            1           17h
[pjiandan@pjiandan crds]$ kubectl get pvc
NAME             STATUS   VOLUME                                     CAPACITY   ACCESS MODES   STORAGECLASS   AGE
mysql-pv-claim   Bound    pvc-9ee52dce-b7b7-433d-8596-22392033e55e   10Gi       RWO            standard       17h
wp-pv-claim      Bound    pvc-8674f3fa-acb3-4cd7-9283-5ecec8305945   10Gi       RWO            standard       16h

Run the following command to get the IP Address for the Wordpress Service:

minikube service wordpress --url

The response should be like this:

http://192.168.99.101:31881

Copy the IP address and load the page in your browser to view your site:

Questions

Please feel free to open up an issue.

Note

The current operator code uses deprecated operator-sdk version. Please refer here for operator-sdk v1+