Vinayak Salunke's Blog

Helm - flask app deployment

Vinayak Salunkhe's photo
Vinayak Salunkhe
·

4 min read

Prerequisite:-

Refer to my last blog for Kubernetes cluster setup and manual application deployment.

https://yes-we-can-devops.hashnode.dev/deploying-flask-applications-on-kubernetes

What is Helm & Helm charts

https://hashnode.com/edit/clnvy0m87000009ig2bcwfu5l

To Install helm and add helm repository in Ubuntu.

curl https://baltocdn.com/helm/signing.asc | gpg --dearmor | sudo tee /usr/share/keyrings/helm.gpg > /dev/null
sudo apt-get install apt-transport-https --yes
echo "deb [arch=$(dpkg --print-architecture) signed-by=/usr/share/keyrings/helm.gpg] https://baltocdn.com/helm/stable/debian/ all main" | sudo tee /etc/apt/sources.list.d/helm-stable-debian.list
sudo apt-get update
sudo apt-get install helm

Commands:

  • sudo apt install bash-completion

  • alias k='kubectl'

  • vim ~/.bashrc

To add aliases (shortcuts for commands) in ~/.bashrc file. To enable auto-completion.

Add below lines:-

  • alias k='kubectl'

  • alias kgp='kubectl get pods'

  • alias kga='kubectl get all'

  • alias a='kubectl get all -A'

  • source <(kubectl completion bash)

  • source <(helm completion bash)

Save the file and exit. (Shift+zz)

  • mkdir two-tier-app

  • cd two-tier-app/

  • helm create mysql-chart

  • cd mysql-chart/

  • ls

  • vim values.yaml

  •         image:
          repository: mysql
          pullPolicy: IfNotPresent
          tag: "latest"Add:

  •         service:
          type: ClusterIP
          port: 3306

env:
  mysqlrootpw: admin
  mysqldb: mydb
  mysqluser: admin
  mysqlpass: admin
  • vim templates/deployment.yaml

Add the below contents:

env:
  - name: MYSQL_ROOT_PASSWORD
    value: "{{ .Values.env.mysqlrootpw }}"
  - name: MYSQL_DATABASE
    value: "{{ .Values.env.mysqldb }}"
  - name: MYSQL_USER
    value: "{{ .Values.env.mysqluser }}"
  - name: MYSQL_PASSWORD
    value: "{{ .Values.env.mysqlpass }}"

  • cd ..

  • ls

  • helm package mysql-chart/

  • helm install mysql-chart ./mysql-chart

  • k get all

  • k get all

  • vim mysql-chart/templates/deployment.yaml

  • delete or # the 1) livenessProbe: and 2) livenessProbe: sections.

  • helm list

  • helm uninstall mysql-chart

  • helm package mysql-chart

  • helm install mysql-chart ./mysql-chart

  • k get all

Go to the worker node (ssh into node) and run the below commands:

  • docker ps

  • docker exec -it 1e0b78b2f125 bash (Change container ID of yours)

  • mysql -u admin -p

  • admin

  • use mydb;

  •         CREATE TABLE messages (
            id INT AUTO_INCREMENT PRIMARY KEY,
            message TEXT
        );

  • SELECT * FROM messages;

The database is empty.

Go to the master node (ssh into node) and run the below commands:

  • helm create flask-app-chart

  • ls

  • cd flask-app-chart/

  • ls

  • k get svc =Copy the MySQL service IP

  • vim values.yaml

Add the below contents:

  •       image:
        repository: yesicanvinayak/projects
        pullPolicy: IfNotPresent
        # Overrides the image tag whose default is the chart appVersion.
        tag: "flaskapp"

      env:
        mysqlhost: 10.99.113.204 # This should be IP of your mysql service.
        mysqldb: mydb
        mysqluser: admin
        mysqlpass: admin

  •       service:
        type: NodePort
        port: 80
        targetPort: 5000
        nodePort: 30007

Check the below screenshots for your reference.

Save and exit.

  • vim templates/deployment.yaml

Add the below contents:

env:
  - name: MYSQL_HOST
    value: "{{ .Values.env.mysqlhost }}"
  - name: MYSQL_DB
    value: "{{ .Values.env.mysqldb }}"
  - name: MYSQL_USER
    value: "{{ .Values.env.mysqluser }}"
  - name: MYSQL_PASSWORD
    value: "{{ .Values.env.mysqlpass }}"
ports:
  - name: http
    containerPort: {{ .Values.service.targetPort }}
    protocol: TCP
                # livenessProbe:
                #   httpGet:
                #     path: /
                #     port: http
                # readinessProbe:
                #   httpGet:
                #     path: /
                #     port: http

Check the below screenshots for your reference.

vim templates/service.yaml

Add the below contents:

  •       ports:
          - port: {{ .Values.service.port }}
            targetPort: {{ .Values.service.targetPort }}
            nodePort: {{ .Values.service.nodePort }}
            protocol: TCP
            name: http

Check the below screenshots for your reference.

  • cd ..

  • helm template flask-app-chart

Check all template values and make sure all are correct.

  • helm package flask-app-chart/

  • helm install flask-app-chart-release-1 ./flask-app-chart

  • k get all

Open the AWS console and copy the worker node's public IP

Open the 30007 port in the security group > edit inbond rule.

Open the browser and enter the worker node's public IP:30007

http://13.235.17.198:30007/

Go to the worker node (ssh into node) and run the below commands:

  • docker ps

  • docker exec -it 1e0b78b2f125 bash (Change container ID of yours)

  • mysql -u admin -p

  • admin

  • use mydb;

  • SELECT * FROM messages;

🎉 Congratulation! 🎉 Your data has been successfully injected into the database. 💾🚀

To uninstall the charts:

  • helm list

  • helm uninstall flask-app-chart-release-1 mysql-chart

  • helm list

If you find the blog helpful, please do like it and share it with your friends. If you have any doubts or questions related to the topics covered in the blog, feel free to ask them in the comments section. I'll be more than happy to help! 😊👍👥

Helmhelm chart#90daysofdevopsflaskapp