Oracle Linux and MySQL, Kafka and Python Flask Monitoring API

In this entry we will dig deeper into the previous post that dealt with invoking an Oracle MySQL stored procedure using Python. The focus of this entry is creating a Python API to monitor Kafka and MySQL running on an Oracle Linux VM. This API can be invoked from a User Interface that will allow the user to check the statuses of these different components.

To create a Python API that will execute the commands on your Oracle Linux or RHEL system to check the status of MySQL, Zookeeper, and Kafka, you can use the subprocess module in Python to run shell commands. 

Below is an example of how you can implement this.

Step-by-Step Implementation:

• Create Python Functions to Check Status: Each function will execute the corresponding system command using subprocess.run and return the output.
• Set Up Flask API: We'll use Flask to create a simple API that the UI can call to retrieve the status.

Python Code:

import subprocess
from flask import Flask, jsonify
app = Flask(__name__)

# Function to check MySQL status
def check_mysql_status():
try:
result = subprocess.run(['sudo', 'systemctl', 'status', 'mysqld'], capture_output=True, text=True)
return result.stdout
except subprocess.CalledProcessError as e:
return str(e)

# Function to check Zookeeper status
def check_zookeeper_status():
try:
result = subprocess.run(['sudo', 'systemctl', 'status', 'zookeeper'], capture_output=True, text=True)
return result.stdout
except subprocess.CalledProcessError as e:
return str(e)

# Function to check Kafka status
def check_kafka_status():
try:
result = subprocess.run(['sudo', 'systemctl', 'status', 'kafka'], capture_output=True, text=True)
return result.stdout
except subprocess.CalledProcessError as e:
return str(e)

# Flask API route to get MySQL status
@app.route('/status/mysql', methods=['GET'])
def get_mysql_status():
status = check_mysql_status()
return jsonify({'service': 'MySQL', 'status': status})

# Flask API route to get Zookeeper status
@app.route('/status/zookeeper', methods=['GET'])
def get_zookeeper_status():
status = check_zookeeper_status()
return jsonify({'service': 'Zookeeper', 'status': status})

# Flask API route to get Kafka status
@app.route('/status/kafka', methods=['GET'])
def get_kafka_status():
status = check_kafka_status()
return jsonify({'service': 'Kafka', 'status': status})

if __name__ == "__main__":
app.run(host='0.0.0.0', port=5000)

Explanation:

• subprocess.run: Executes the systemctl commands to check the status of MySQL, Zookeeper, and Kafka. The capture_output=True argument captures the output, while text=True ensures the output is returned as a string.
• Flask: Provides an API endpoint for each service, which the UI can call to check the respective statuses.
• Routes: Each API route (/status/mysql, /status/zookeeper, /status/kafka) responds to a GET request and returns the status of the requested service in JSON format.

Running the API:

To run the Flask API, ensure Flask is installed:

pip install Flask

To Start the Application:

python your_script_name.py

Creating the UI:

For the UI, you can use any front-end technology (HTML, React, etc.) and have buttons that call these API endpoints to display the status of each service.

For example:

• A button for MySQL could call /status/mysql.
• A button for Kafka could call /status/kafka.
• A button for Zookeeper could call /status/zookeeper.

Note on Permissions:

Ensure that the user running the Python script has the appropriate permissions to run the systemctl commands using sudo. You may need to modify the sudoers file to allow passwordless sudo for these commands.