JS7 JobScheduler

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Introduction

  • JS7 can be set up for use with a Kubernetes Cluster. Using the Linux based JS7 images for Docker® containers which ship with a current Alpine base image and OpenJDK.
  • Users deploy JS7 products by creating a Kubernetes deployment object from a deployment YAML file.
    • To this purpose users have to first install and set up the Kubernetes Cluster see JS7 - How to install a Kubernetes Cluster.
    • With the Kubernetes Cluster being up and running users can use YAML deployment files to deploy JS7 products.

Deployment Files

The YAML sample files for deployment to Kubernetes are attached to the article.

Download the archive file: js7-kubernetes.zip

The archive includes the following files.

Deployment of JS7 Products: js7-deployment.yaml

Example for js7-deployment.yaml
apiVersion: v1
kind: Pod
metadata:
  creationTimestamp: null
  labels:
    run: js7joc
  name: js7joc
spec:
  volumes:
  - name: hibernate-config
    configMap:
        name: hibernate-config
  containers:
  - image: sosberlin/js7:joc-2-5-1
    name: js7joc
    ports:
    - containerPort: 4446
    volumeMounts:
    - name: hibernate-config
      mountPath: /var/sos-berlin.com/js7/joc/resources/joc/
  
    env:
    - name: RUN_JS_JAVA_OPTIONS
      value: "-Xmx256m"
    - name: RUN_JS_USER_ID
      value:  "0:0"
      
  - image: sosberlin/js7:controller-2-5-1
    name: js7con
    ports:
    - containerPort: 4444
    env:
    - name: RUN_JS_JAVA_OPTIONS
      value: "-Xmx256m"
    - name: RUN_JS_USER_ID
      value:  "0:0"
    - name: RUN_JS_ID
      value:  "jobscheduler"
      
  - image: sosberlin/js7:agent-2-5-1
    name: js7agent
    ports:
    - containerPort: 4445
    env:
    - name: RUN_JS_JAVA_OPTIONS
      value: "-Xmx256m"
    - name: RUN_JS_USER_ID
      value:  "0:0"


The YAML file describes a single Pod for deployment to Kubernetes which is a group of one or more containers and a ConfigMap. The Pod includes three containers:

  1. The js7joc container runs the joc-2-5-1 image and exposes port 4446. It uses a ConfigMap with the name hibernate-config to specify a volume mounted to the /var/sos-berlin.com/js7/joc/resources/joc directory. The deployment file specifies a number of environment variables, including RUN_JS_JAVA_OPTIONS, RUN_JS_USER_ID, and RUN_JS_ID.
  2. The js7con container runs the controller-2-5-1 image and exposes port 4444. It sets the environment variables RUN_JS_JAVA_OPTIONS, RUN_JS_USER_ID, and RUN_JS_ID.
  3. The js7agent container runs the agent-2-5-1 image and exposes port 4445. It sets the environment variables RUN_JS_JAVA_OPTIONS, RUN_JS_USER_ID, and RUN_JS_ID.

The following implications apply:

  • Each container runs a different image from the sosberlin/js7 repository and is assigned a unique port.

  • Each container defines environment variables which control a number of runtime parameters for the application such as:

    • RUN_JS_JAVA_OPTIONS : see JS7 - FAQ - Which Java Options are recommended
    • RUN_JS_USER_ID: specifies the numeric User ID and Group ID - separated by a colon - of the run-time account used for the related JS7 product. A value 0:0 indicates the root account and root group, a value 1000:1000 specifies a user account with the given User ID and Group ID. For details see JS7 - Running Containers for User Accounts.
    • RUN_JS_ID: specifies the Controller ID which is a unique identifier for a Standalone Controller or Controller Cluster.

  • For the js7joc container the volumeMounts element specifies the hibernate-config ConfigMap which is mounted to the /var/sos-berlin.com/js7/joc/resources/joc directory.

Configuration for Port Forwarding: js7-service.yaml

Example for js7-service.yaml
apiVersion: v1
kind: Service
metadata:
  creationTimestamp: null
  labels:
    run: js7joc
  name: js7joc
spec:
  ports:

  - name: js7joc
    port: 4446
    protocol: TCP
    targetPort: 4446

  - name: js7agent
    port: 4445
    protocol: TCP
    targetPort: 4445

  - name: js7controller
    port: 4444
    protocol: TCP
    targetPort: 4444
  
  selector:
    run: js7joc
  type: LoadBalancer
status:
  loadBalancer: {}

Hibernate Configuration: hibernate.cfg.xml

This file includes the Hibernate configuration for connections to the JS7 - Database. Find the following example for use with a MySQL® database:

Example for js7-service.yaml
<?xml version="1.0" encoding="UTF-8" standalone="no"?>
<hibernate-configuration>
 <session-factory>
  <property name="hibernate.connection.driver_class">org.mysql.jdbc.Driver</property>
  <property name="hibernate.connection.password">jobscheduler</property>
  <property name="hibernate.connection.url">jdbc:mysql://mysqlsrv:3306/jobscheduler</property>
  <property name="hibernate.connection.username">jobscheduler</property>
  <property name="hibernate.dialect">org.hibernate.dialect.MySQLInnoDBDialect</property>
  <property name="hibernate.show_sql">false</property>
  <property name="hibernate.connection.autocommit">false</property>
  <property name="hibernate.format_sql">true</property>
  <property name="hibernate.temp.use_jdbc_metadata_defaults">false</property>
  <property name="hibernate.connection.provider_class">org.hibernate.hikaricp.internal.HikariCPConnectionProvider</property>
  <property name="hibernate.hikari.maximumPoolSize">10</property>
 </session-factory>
</hibernate-configuration>

Step-by-Step Instructions

To operate JOC Cockpit in a Kubernetes Cluster with the JS7 database users adjust the hibernate.cfg.xml file that specifies the database connection and that holds credentials for database access. Find further examples from the JS7 - Database article.

  1. Download the archive file: js7-kubernetes.zip. Open a console window from the directory where you downloaded the .zip archive and extract the archive.

  2. Execute the below command to create a ConfigMap and to pass the hibernate.cfg.xml file to the mount directory of the container.

    kubectl create configmap hibernate-config --from-file=hibernate.cfg.xml



  3. Run the js7-deployment.yaml file to create the deployment for the JS7 configuration.

    kubectl create -f js7-deployment.yaml



  4. Run the js7-service.yaml file to create the service for the JS7 configuration.

    kubectl create -f js7-service.yaml



  5. Once both YAML files are executed successfully, users can check the Pods' status. The following command displays Pods running in the Kubernetes Cluster.

    kubectl get pods



  6. Once both YAML files are executed successfully, users can check the steps from the YAML file executed to create the Pod. The following command displays resources used in Kubernetes. It shows data from a single resource and from a collection of resources.

    kubectl describe pods



  7. The following command can be executed to check the IP address and port of JS7 products.

    kubectl get service

Further Resources