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1. A Kubernetes cluster consists of one or more nodes. Nodes are machines (VMs, physical servers, etc) that run the applications.

   Thai
   คลัสเตอร์ Kubernetes ประกอบด้วยหนึ่งโหนดขึ้นไป Nodes คือเครื่อง (VM, ฟิสิคัลเซิร์ฟเวอร์ ฯลฯ ) ที่รันแอ็พพลิเคชัน

2. A Pod is the smallest Kubernetes object that contains one or more containers, storage resources, network IP and other configuration.

   Thai
   Pod เป็นวัตถุ Kubernetes ที่เล็กที่สุดที่มีหนึ่งคอนเทนเนอร์ขึ้นไปทรัพยากรหน่วยเก็บข้อมูล IP เครือข่ายและการกำหนดค่าอื่น ๆ

3. A Service defines a set of Pods and how they are accessed.

   Thai
   ไดรฟ์ข้อมูล Service เป็นที่เก็บข้อมูลที่ใช้ร่วมกันสำหรับตู้คอนเทนเนอร์และรองรับหลายประเภท

4. A Volume is a shared storage for containers, and many different types are supported.

   Thai
   ไดรฟ์ข้อมูล Volume เป็นที่เก็บข้อมูลที่ใช้ร่วมกันสำหรับตู้คอนเทนเนอร์และรองรับหลายประเภท

5. These Kubernetes objects are defined in YAML format in .yaml files

   Thai
   วัตถุ Kubernetes เหล่านี้ถูกกำหนดในรูปแบบ YAML ในไฟล์. yaml

6. A command line interface tool, kubectl, is used to manage these objects via the Kubernetes API.

   Thai
   เครื่องมืออินเตอร์เฟสบรรทัดคำสั่ง kubectl, ใช้เพื่อจัดการวัตถุเหล่านี้ผ่าน Kubernetes API.

Image Modified

Simplified view of Kubernetes objects

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minikube v1.8.1 on Darwin 10.14.6
Automatically selected the hyperkit driver
Downloading VM boot image ...
Creating hyperkit VM (CPUs=2, Memory=3072MB, Disk=20000MB) ...
Preparing Kubernetes v1.17.3 on Docker 19.03.6 ...
Launching Kubernetes ... 
Enabling addons: default-storageclass, storage-provisioner
Waiting for cluster to come online ...
Done! kubectl is now configured to use "minikube"

2. Install Ingress on Minikube for external access:

minikube addons enable ingress

Test Minikube Installation

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kubectl create rundeployment hello-minikube --image=k8s.gcr.io/google_containers/echoserver:1.4 --port=808010

2. Expose the service so that external connections can be made

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kubectl expose deployment hello-minikube --type=NodePort --port=8080

3. Inspect the pod

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kubectl apply -f https://k8s.io/examples/application/mysql/mysql-pv.yaml

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Once the MySQL database is running, let’s run a Docker image for Joget Enterprise that connects to that MySQL service.

1. Deploy joget image using an example YAML file. Download the contents of joget-dxdx7-tomcat9-deployment.yaml into a file with the same name and run kubectl.

kubectl apply -f joget-dxdx7-tomcat9-deployment.yaml

2. Inspect the deployment

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kubectl describe deployment joget-dx7-tomcat9
kubectl get pods -l app=joget-dx7-tomcat9

3. Once the STATUS is Running, get the URL for the service

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minikube service joget-dx7-tomcat9 --url

4. Access the URL in a browser with an additional /jw in the path to access the Joget App Center e.g. http://192.168.99.100:32496/jw

5. Access the Joget DX URL and in the Database Setup page, key in the database configuration of the database deployed earlier, and click on the Save button.
Image Added

1. Database Type: MySQL
2. Database Host: the service name of the database e.g. mysql
3. Database Port: 3306
4. Database Name: jwdb
5. Database User: root
6. Database Password: the configured password e.g. password

Image Modified

You now have a running installation of Joget, and you’ll be able to visually build a full app in 30 minutes without coding.

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kubectl scale --replicas=2 deployment joget-dx7-tomcat9

2. Examine the running pods, and you should see 2 pods running Joget

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kubectl get pods
NAME                     READY STATUS RESTARTS   AGE
joget-dx7-tomcat9-7d879db895-c9sbb   1/1 Running 0    27s
joget-dx7-tomcat9-7d879db895-wpnsf   1/1 Running 0    37m
mysql-7b9b7999d8-lk9gq   1/1 Running 0    65m

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kubectl scale --replicas=1 deployment joget-dx7-tomcat9

4. Examine the running pods, and you should now see 1 pod running Joget.

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kubectl get pods

Common Errors

How to Validate Your Installation System Key

1. Launch Joget from your browser and login as admin.
2. Navigate to Settings > License.
3. Your system key should contains dashes as the following. 
   Image Added
   If the system key matches any of the nodes listed at the bottom, then it is wrong.
4. If it does not, chances are that you did not assign the service account cluster view permission for Joget to retrieve the deployment info.
   Check the logs to look for "io.kubernetes.client.openapi.ApiException: Forbidden".

   ERROR 14 Apr 2021 12:35:03 org.joget.apps.license.LicenseManager  - Forbidden
   io.kubernetes.client.openapi.ApiException: Forbidden
   	at io.kubernetes.client.openapi.ApiClient.handleResponse(ApiClient.java:971)
   	at io.kubernetes.client.openapi.ApiClient.execute(ApiClient.java:883)
   	at io.kubernetes.client.openapi.apis.CoreV1Api.readNamespacedPodWithHttpInfo(CoreV1Api.java:45995)
   	at io.kubernetes.client.openapi.apis.CoreV1Api.readNamespacedPod(CoreV1Api.java:45965)
   	at org.joget.apps.license.LicenseManager.generateK8sDeploymentSystemKey(LicenseManager.java:934)
   	at org.joget.apps.license.LicenseManager.generateClusterSystemKey(LicenseManager.java:854)
   	at org.joget.apps.license.LicenseManager.checkClusterLicense(LicenseManager.java:1055)
   	at org.joget.apps.license.LicenseManager$4.run(LicenseManager.java:1029)

   
   

5. The "io.kubernetes.client.openapi.ApiException: Forbidden"exception shows this permission is missing. You may need to change namespace value if they are not using the default namespace. Once that you have resolved this error, then only the system key would change back to using the deployment ID.

6. The following in the YAML file.
   
   apiVersion: rbac.authorization.k8s.io/v1
   kind: ClusterRoleBinding
   metadata:
     name: joget-dx7-tomcat9-clusterrolebinding
   roleRef:
     apiGroup: rbac.authorization.k8s.io
     kind: ClusterRole
     name: view
   subjects:
     - kind: ServiceAccount
       name: default
       namespace: default
   
   is to assign the service account cluster view permission to retrieve Deployment info for the license system key.