Table of Contents

Introduction

JS7 can be set up using for use with a Kubernetes cluster on a Server. Using the Linux - based JS7 images for Docker® containers which ship with a current Alpine base image and OpenJDK.
- Docker® images for JS7 are publicly available from https://hub.docker.com/r/sosberlin/js7.
- Instructions on how to run containers for JS7 components can be found
in the articles listed below.
- from the JS7 - Installation for Docker Containers article series.
Users can run JS7 components You can run an application by creating a Kubernetes Deployment deployment object, and you can describe a Deployment the deployment in a YAML file. To do so we need
- To this purpose users have to first install and set up the Kubernetes
cluster, once it is completed you can use the deployment YAML files to deploy JS7.

Setting up a Kubernetes Cluster

There are several ways how to set up a Kubernetes Cluster. Find an example from the following chapters.

The basic step which can be followed to install the Kubernetes cluster on Centos are:

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Install Docker on all CentOS 7 VMs

Update the package database
Code Block
sudo yum check-update

Install the dependencies

Code Block
sudo yum install -y yum-utils device-mapper-persistent-data lvm2

Add and enable the official Docker Repository to CentOS 7

Code Block
sudo yum-config-manager --add-repo https://download.docker.com/linux/centos/docker-ce.repo

Install the latest Docker version on CentOS 7
Code Block
sudo yum install docker-ce
A successful installation output will be concluded with a Complete!You may be prompted to accept the GPG key. This is to verify that the fingerprint matches. The format will look as follows. If correct, accept it.
Code Block
060A 61C5 1B55 8A7F 742B 77AA C52F EB6B 621E 9F35
Manage Docker service
Now Docker is installed, but the service is not yet running. Start and enable Docker using the commands.
Code Block
sudo systemctl start docker sudo systemctl enable docker
To confirm that Docker is active and running, use:
Code Block
sudo systemctl status docker

Set up the Kubernetes Repository

...

Since the Kubernetes packages aren’t present in the official CentOS 7 repositories, we will need to add a new repository file. Use the following command to create the file and open it for editing:

Code Block
sudo vi /etc/yum.repos.d/kubernetes.repo

Once the file is open, press the I key to enter insert mode and paste the following contents:

Code Block

[kubernetes]
name=Kubernetes
baseurl=https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://packages.cloud.google.com/yum/doc/yum-key.gpg https://packages.cloud.google.com/yum/doc/rpm-package-key.gpg

Once pasted, press escape to exit insert mode. Then enter :x to save the file and exit.

- Cluster see JS7 - How to install a Kubernetes Cluster.
- With the Kubernetes Cluster being up and running users can use the deployment YAML files to deploy JS7 components.

Deployment Files

The sample YAML files for use with

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Install Kubelet on CentOS 7

The first core module that we need to install on every node is Kubelet. Use the following command to do so:
Code Block
sudo yum install -y kubelet

Install kubeadm and kubectl on CentOS 7

kubeadm, the next core module, which has to be installed. Use the following command:

Code Block
sudo yum install -y kubeadm

(Note that kubeadm automatically installs kubectl as a dependency)

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Disable swap

For Kubelet to work, we also need to disable swap. The swap can be disabled using the below commands:
Code Block
sudo swapoff -a sudo sed -i '/ swap / s/^/#/' /etc/fstab

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Initialize Kubeadm and start the Kubernetes cluster

When we initialize the kubeadm directly, then the kubeadm throws the error:

Code Block

Some fatal errors occurred: [ERROR CRI]: container runtime is not running Status from runtime service failed” err=”rpc error: code = Unimplemented desc = unknown service runtime.v1alpha2.RuntimeService”

To resolve the above error, it is required to delete the config.tomal file and restart contained using the below steps:
Code Block
sudo rm /etc/containerd/config.toml systemctl restart containerd

Initialize Kubeadm and Create required directories and start managing Kubernetes cluster

Code Block
sudo kubeadm init mkdir $HOME/.kube sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config sudo chown $(id -u):$(id -g) $HOME/.kube/config export KUBECONFIG=/etc/kubernetes/admin.conf

Enable and restart docker and Kubernetes services.

Code Block
sudo systemctl enable docker.service sudo service kubelet restart sudo chown -R centos:centos kubernetes/

Set up Pod network for the Cluster.

Code Block
kubectl apply -f https://raw.githubusercontent.com/coreos/flannel/2140ac876ef134e0ed5af15c65e414cf26827915/Documentation/kube-flannel.yml kubectl get nodes

Following the above steps, the setup of the Kubernetes cluster is successful. Now you can create the Kubernetes YAML files and deploy the JS7 on this Kubernetes cluster.

Deploying JS7 on Kubernetes

The example YAML files of Kubernetes are attached to the article.

Download the archive file: js7-kubernetes.zip

attached zip file. The folder structure includes three the following files:

js7-deployment.yaml – This file is the deployment file for

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JS7 components.

Code Block

language	yml
title	Example js7-deployment.yaml
linenumbers	true
collapse	true

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"
    - name: RUN_JS_ID
      value:  "jobscheduler"
      
  - 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

js7-service.yaml – This file includes the configuration

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for port forwarding.

Code Block

language	yml
title	Example js7-service.yaml
linenumbers	true
collapse	true

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.cfg.xml – This

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

Code Block

language	yml
title	Example js7-service.yaml
linenumbers	true
collapse	true

<?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 To make the Kubernetes cluster run according to your database environment, you can adjust the hibernate.cfg.xml file with your database credentials. The default file is MySql. You can use the hibernate.cfg.xml files of the other database from JS7 - Database.
The zip file, including the above configuration files, is that specifies the database connection and holds credentials for database access. Find further examples from the JS7 - Database article.

Download the archive file: js7-kubernetes.zip.

...

Open a console window from the directory where you downloaded the .zip archive and extract the archive.
Execute the below command to
Open CMD from the folder where you unzip the attached ZIP.
To create a config map and to pass the and to pass this hibernate.cfg.xml file to the mount directory of the container, follow the below command.
Code Block
kubectl create configmap hibernate-config --from-file=hibernate.cfg.xml
To Run the js7-deployment.yaml file to create the service of deployment for the JS7 configuration, you need to run the js7-service.yaml file:
Code Block
kubectl create -f js7-deployment.yaml
To Run the js7-service.yaml file to create the deployment of service for the JS7 configuration, you need to run the js7-deployment.yaml file:
Code Block
kubectl create -f js7-service.yaml
Once both the YAML files are executed successfully , you users can get check the pod's status. The Kubectl Get Pod is a following command that displays the pods running in the Kubernetes cluster.
Code Block
kubectl get pods
Once both the YAML files are executed successfully , you users can describe Pod and check each step in check the steps from the YAML file is executed successfully or not. The Kubectl Describe Pod is a command that describes any resource executed to create the pod. The following command displays resources used in Kubernetes. It shows data on from a single or even resource and from a collection of resources.
Code Block
kubectl describe pods
To The following command can be executed to check the IP address and Port of the running JOC Cockpit, execute the kubectl get service commandport of JS7 components.
Code Block
kubectl get service

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Key

Introduction

Setting up a Kubernetes Cluster

Install Docker on all CentOS 7 VMs

Set up the Kubernetes Repository

Deployment Files

Install Kubelet on CentOS 7

Install kubeadm and kubectl on CentOS 7

Disable swap

Initialize Kubeadm and start the Kubernetes cluster

Deploying JS7 on Kubernetes

Step-by-Step Instructions

Space shortcuts

Page tree

Page History

Versions Compared

Old Version 1

New Version 2

Key

Introduction

Setting up a Kubernetes Cluster

Install Docker on all CentOS 7 VMs

Set up the Kubernetes Repository

Deployment Files

Install Kubelet on CentOS 7

Install kubeadm and kubectl on CentOS 7

Disable swap

Initialize Kubeadm and start the Kubernetes cluster

Deploying JS7 on Kubernetes

Step-by-Step Instructions