Development Environment on Kubernetes cluster

Description

Developers use different software languages to develop applications. Usually, due to local environment differences, developers observe different outputs from the same codebase. For a smooth development process, this shouldn’t be the case.

This project's aim is preparing Docker containers to standardize the development environments and solve this and similar issues.

To achieve this, I have used Vagrant for instance provisioning, Kubernetes as the container orchestration and Ansible for configuration automation. The project has aimed a demo Python application but you can use any language depends on your current development software language such as Golang, Java, etc.

There are 3 core steps:

• VM provisioning by using Vagrant
• Kubernetes cluster installation by using Ansible
• Application build script for building a local image and deploy

Demo application

• Application has been written by using Python3
• The application needs a MySQL database for datastore
• You can build the application by using build.sh script.
• Vagrant syncs the repo's root folder to the /vagrant path of the VMs. So you don't need to copy the changed files to the VM for the build process.
• The application uses the following environment variables:
  • MYSQL_USERNAME
  • MYSQL_PASSWORD
  • MYSQL_INSTANCE_NAME
  • MYSQL_PORT_3306_TCP_ADDR
  • MYSQL_PORT_3306_TCP_PORT

Features

• You can able to increase or decrease Kubernetes cluster size by editing the environment variables inside of the Vagrantfile.
• If you need more instances for testing purposes like application availability test on multi-node, just increase the node size inside of the Vagrantfile.
• Persistency can be enabled on the Kubernetes cluster by using Persistent Volume (PV) and Persistent Volume Claim (PVC).
• MySQL pod uses PVC for the persistent data store

Requirements

• Vagrant 2.2.9 or later: https://www.vagrantup.com/downloads.html
• Ansible 2.9.12 or later: https://docs.ansible.com/ansible/latest/installation_guide/intro_installation.html#installing-the-control-machine

Automation Outputs

• 2 VM instances
• Kubernetes cluster - 1 master, 1 node
• Containerized Python application

Project Structure

.
├── LICENSE
├── README.md
├── Vagrantfile
├── app
│   ├── Dockerfile
│   ├── app.py
│   ├── app.yaml
│   ├── mysql.yaml
│   └── requirements.txt
├── build.sh
├── group_vars
│   └── all
├── k8s-configs
│   ├── config
│   └── join-command
├── roles
│   ├── docker
│   │   └── tasks
│   │       ├── install.yaml
│   │       └── main.yml
│   ├── k8s-install
│   │   └── tasks
│   │       ├── install.yaml
│   │       └── main.yml
│   ├── master
│   │   └── tasks
│   │       ├── install.yaml
│   │       └── main.yaml
│   └── node
│       └── tasks
│           ├── install.yaml
│           └── main.yaml
├── setup.yaml

Example Usage

Installation

• Clone the repository and navigate to the repo's root folder

• Run vagrant up command. This will provision 2 VMs which are master and node instances. Then the ansible-playbook will install the Kubernetes cluster as 1 master and 1 node.

• Run cat ./build.sh | vagrant ssh node-1 command to build and deploy the application to the Kubernetes cluster. After the execution, you should see the information like below:

#########
 The application is running on the 'busayr/hello-devops-dev:4932133f558e' image.
 ----------------------------------------------------------
 You can access http://192.168.50.11:30300
#########

Update

• You need to run vagrant provision after ansible-playbook configuration changes.

Clean-up

• You can remove the environment by using vagrant destroy command.

License

Apache License 2.0