Table of Contents

Introduction

JS7 can be set up using 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.
You can run an application by creating a Kubernetes Deployment object, and you can describe a Deployment in a YAML file. To do so we need 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

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

Add and enable the official Docker Repository to CentOS 7

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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.
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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.
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sudo systemctl start docker sudo systemctl enable docker
To confirm that Docker is active and running, use:
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sudo systemctl status docker

Set up the Kubernetes Repository

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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.

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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:
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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:

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

js7-deployment.yaml – This file is the deployment file for the JS7

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 includes the configuration of 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 is the hibernate file for connection to the 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>

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The zip file, including the above configuration files, is js7-kubernetes.zip. After downloading the attached file, follow the below steps to deploy the container:

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To create a config map and 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

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To create the service of the JS7 configuration, you need to run the js7-service.yaml file:

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kubectl create -f js7-deployment.yaml

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To create the deployment of the JS7 configuration, you need to run the js7-deployment.yaml file:

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kubectl create -f js7-service.yaml

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Once both the YAML files are executed successfully, you can get the pod's status. The Kubectl Get Pod is a command that displays the pods running in the Kubernetes cluster.

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kubectl get pods

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Once both the YAML files are executed successfully, you can describe Pod and check each step in the YAML file is executed successfully or not. The Kubectl Describe Pod is a command that describes any resource in Kubernetes. It shows data on a single or even a collection of resources.

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kubectl describe pods

To check the IP and Port of the running JOC Cockpit, execute the kubectl get service command.

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Key

Introduction

Setting up a Kubernetes Cluster

Install Docker on all CentOS 7 VMs

Set up the Kubernetes Repository

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

Space shortcuts

Page tree

Page History

Versions Compared

Old Version 8

New Version Current

Key

Introduction

Setting up a Kubernetes Cluster

Install Docker on all CentOS 7 VMs

Set up the Kubernetes Repository

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