TerraGuard - Health Check

Health Check RESTful API¶ This project implements a Health Check RESTful API to monitor the status of a web application. By utilizing this API, you can detect when a service instance is unable to handle requests, allowing for proactive management such as stopping traffic to unhealthy instances and automatically replacing or repairing them. This approach enhances user experience by ensuring requests are not routed to malfunctioning instances. The question we want to answer is How to detect that a running service instance is unable to handle requests?. The health check API is a way for us to monitor the health of the application instance and alerts us when something is not working as expected. Health check API allows us to stop sending traffic to unhealthy instances of the application and to automatically replace/repair them. It also helps us improve user experience by not routing their quests to unhealthy instances.

Features

Database used : PostgreSQl - Health Check Endpoint: Provides real-time status of the application instance. ORM Framework : Sequilize (node js) - User Management Endpoint: Allows for user-related operations.

• Database Integration: Utilizes PostgreSQL for data storage.
• ORM Framework: Implements Sequelize for database interactions.
• Packer Integration: Facilitates the creation of machine images for deployment.

Health check endpoint: /healthz ## Prerequisites User endpoint: /v1/user/self

Steps: - Node.js: Version 18.x

1. npm install and run node index.js - PostgreSQL: Version 16.x
2. W + R => services.msc - Packer: Installed and configured
3. start and stop the server - Google Cloud SDK: For managing Google Cloud resources
4. check for different endpoint and different REST method
5. check for payload
6. update test to fail the workflow
7. node version 18
8. postgreSQL version 16

Setup Instructions

commands for packer: 1. Clone the Repository:

git clone https://github.com/sankhlatarunorg/webapp.git
cd webapp

2. Install Dependencies:

   npm install

3. Configure Environment Variables:

   • Create a .env file in the root directory.
   • Add the following variables:

     DB_HOST=your_database_host
     DB_USER=your_database_user
     DB_PASSWORD=your_database_password
     DB_NAME=your_database_name
     

4. Initialize the Database:

   • Ensure PostgreSQL is running.
   • Run migrations (if applicable) to set up the database schema.

5. Start the Application:

   node server.js

6. Access the Endpoints:

   • Health Check: GET /healthz
   • User Management: GET /v1/user/self

Packer Integration

To create a machine image using Packer:

1. Install Packer Plugins:

   packer plugins install github.com/hashicorp/googlecompute	   packer plugins install github.com/hashicorp/googlecompute

packer init ```

2. Initialize Packer:

   packer init .

3. Validate the Packer Template:

   packer validate webappImage.json	   packer validate webappImage.json

4. Build the Image:

   packer build webappImage.json	   packer build webappImage.json

gcloud projects add-iam-policy-binding csye-6225-tarun-002294529 --member=serviceAccount:[email protected] --role roles/compute.imageUser ```

5. Assign IAM Policy: Replace csye-6225-tarun-002294529 with your project ID:

   gcloud projects add-iam-policy-binding csye-6225-tarun-002294529 \
     --member=serviceAccount:[email protected] \
     --role=roles/compute.imageUser

Additional Commands

• Update Google Cloud Components:

  gcloud components update	  gcloud components update

if you want revert - Revert Google Cloud Components to a Specific Version:

gcloud components update --version 463.0.0	  gcloud components update --version 463.0.0

• Upgrade Packer Template to HCL2:

  packer hcl2_upgrade -with-annotations webappImage.json	  packer hcl2_upgrade -with-annotations webappImage.json

packer build webappImage.json.pkr.hcl ```

• Validate Packer Template with Variables:

  packer validate \
    -var 'project_id=csye-6225-tarun-002294529' \
    -var 'zone=us-east1-b' \
    -var 'image_name=csye6225-image-a3' \
    -var 'credentials_file=credentials.json' \
    -var 'source_image=centos-stream-8-v20240110' \
    webappImage.json.pkr.hcl

• Check Google Cloud Ops Agent Status:

  sudo systemctl status google-cloud-ops-agent

packer validate -var 'project_id=csye-6225-tarun-002294529' -var 'zone=us-east1-b' -var 'image_name=csye6225-image-a3' -var 'credentials_file=credentials.json' -var 'source_image=centos-stream-8-v20240110' webappImage.json.pkr.hcl ## Notes

• Ensure that the PostgreSQL server is running and accessible.
• Update the .env file with your specific database credentials.
• Regularly monitor the health endpoint to maintain optimal application performance.

sudo systemctl status google-cloud-ops-agent For more detailed information, refer to the Express.js, Sequelize, and Packer official documentation.