OpenShift demo

This is a simple project composed of three main components demonstrating the OpenShift Local capabilities:

1. A Python program that fetches weather data from openmeteo, packaged into a Docker image.
2. A MySQL database, sourced from the OpenShift Local app store.
3. A web service written in Python (Flask), which queries the MySQL database and displays the data.

Prerequisites

Before you can run this project, you need to have the following installed:

• OpenShift Local
• MySQL Database from the OpenShift app store. After installing OpenShift Local, you can deploy the default MySQL database from the OpenShift app store.

Weather Fetcher

The Docker image location: janezmk/troia-web-app:latest.

This component is deployed as a Kubernetes Job. The job configuration is defined in the fetch-weather.yml file.

apiVersion: batch/v1
kind: Job
metadata:
  name: troia-web-app-job
spec:
  template:
    metadata:
      labels:
        app: troia-web-app
    spec:
      containers:
      - name: troia-web-app
        image: janezmk/troia-web-app:latest
        imagePullPolicy: Always
        envFrom:
        - configMapRef:
            name: db-config
      restartPolicy: Never
  backoffLimit: 4

Web Service

The web service is a Flask application that queries the MySQL database and displays the data. Docker image location: docker.io/janezmk/troia-front-webapp:latest.

This component is deployed as a Kubernetes Deployment. The deployment configuration is defined in the webapp/front-weather.yml file.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: troia-front-webapp-deployment
  labels:
    app: troia-front-webapp
spec:
  replicas: 3
  selector:
    matchLabels:
      app: troia-front-webapp
  template:
    metadata:
      labels:
        app: troia-front-webapp
    spec:
      containers:
      - name: troia-front-webapp
        image: docker.io/janezmk/troia-front-webapp:latest
        imagePullPolicy: Always
        resources:
          limits:
            cpu: "1"
            memory: "512Mi"
        ports:
        - containerPort: 5000
        envFrom:
        - configMapRef:
            name: db-config

Deployment using GUI

1. After sucessfully deploying Openshift Cluster your first choose new project and name it

2. After naming it you navigate to the left sidebar and choose the Add+

3. Then you proceede to choose the Developer Catalog and choose the MySQL database

• Set the properties MySQL Connection Username, MySQL Connection Password , MySQL root user Password , MySQL Database Name
  • Note that these values must be REMEBERED for creating configmap later

4. Before deploying our apps we must create a configmap for the database infromation:

• navigate to the left sidebar and choose ConfigMaps
• On the top right corner choose Create ConfigMap - name it db-config
• Fill in the Key value pairs for DB_HOST-default should be mysql,
• DB_NAME, DB_PASSWORD, DB_USER - same as in step 3
• Proceed with saving the ConfigMap

5. After the deployment of MySQL DB. Click again on the left sidebar and choose Add +.

6. This time choose the IMPORT from Git and paste in the HTTP address of this Github repository link

7. On the next window the OpenShift will autoimport the name which you can change.

• Under Deploy section choose Show advanced deployment options
• There you will proceed to fill out the values of the ConfigMap for each of the properties:
  • DB_HOST, DB_NAME, DB_PASSWORD, DB_USER
• After that you will deploy the app

8. Then you will repeat the step of importing from Git one more time.

• This time we will deploy another Dockerfile which is inside the folder /webapp
• Under Dockerfile on the right side choose Edit import strategy
• Specify different Dockerfile path : webapp/Dockerfile
• This will change the Dockerfile which we build.
• After that scroll down to the Advanced option section
• And set the Target port to 5000

9. After succesfull deployment of the Webservice open up CMD console and expose the service with the following command:

• be sure to login with oc login and choose the corect project.

kubectl port-forward service/rh-starter-webservice 8080:5000 

• Webservice of fetched data is now avaliable on the URL http://localhost:8080/

Deployment CLI

1. Database deployment.

   oc new-app --name=mydatabase mysql-persistent -p MYSQL_USER=myuser -p MYSQL_PASSWORD=mypassword -p MYSQL_DATABASE=weather_data

   Replace myhost, myuser, mypassword, and mydatabase with your actual MySQL host, username, password, and database name.

2. Store the MySQL connection details in a ConfigMap. Use the kubectl create configmap command:

   kubectl create configmap db-config --from-literal=DB_HOST=mysql --from-literal=DB_USER=myuser --from-literal=DB_PASSWORD=mypassword --from-literal=DB_NAME=weather_data

   Replace mysql, myuser, mypassword, and weather_data with your actual MySQL host, username, password, and database name.

3. Apply the Job configuration for the weather fetcher using command:

   kubectl apply -f fetch-weather.yml

4. Apply the Service configuration for the weather web service with command:

   kubectl apply -f webapp/front-weather.yml

5. Expose the Service with command:

   kubectl apply -f webapp/service.yml

6. Expose the port so you can access service locally http://localhost:8080:

   kubectl port-forward service/troia-front-webapp-service 8080:80

With these steps, you should have a running MySQL database, a Job that fetches the weather data and a simple webservice to display the fetched data from MySQL DB.