Docker Container Monitoring Script
Docker Container Monitoring Script
This Python script monitors Docker containers for resource usage (CPU and memory) and sends alert emails when usage exceeds the specified thresholds.
Features
- Monitors all running Docker containers.
- Calculates CPU and memory usage for each container.
- Sends email alerts when CPU or memory usage exceeds defined thresholds.
- Easy to configure thresholds and email settings.
Table of Contents
Prerequisites
- Python: Install Python 3.x on your system.
- Docker: Ensure Docker is installed and running. The script uses the Docker SDK for Python.
- Python Libraries: Install the required libraries using
pip:pip3 install docker
Configuration
-
SMTP Email Settings: Update the following variables in the script:
sender_email: Your email address.password: Your email app password (set up an app-specific password here for Gmail).recipient_email: Add recipient details as a list of dictionaries with name and email.
-
Resource Thresholds:
- Adjust
CPU_THRESHOLDandMEMORY_THRESHOLDto set the percentage usage limits for alerts:CPU_THRESHOLD = 10.0 # CPU usage threshold in percent MEMORY_THRESHOLD = 10.0 # Memory usage threshold in percent
-
Environment Setup
Setting Up a Virtual Environment (Optional)
It’s recommended to use a virtual environment for running the script. Here’s how you can set it up:
python3 -m venv env source env/bin/activate # For Linux/Mac env\Scripts\activate # For Windows
Script
import docker
import smtplib
from email.mime.multipart import MIMEMultipart
from email.mime.text import MIMEText
import logging
import json
logging.basicConfig(level=logging.INFO, format="%(asctime)s - %(levelname)s - %(message)s")
recipient_email = [
{'name': 'abc', 'email': 'abc@gmail.com'}
]
sender_email = "abc@gmail.com"
password = "" # https://myaccount.google.com/u/1/apppasswords
host = "smtp.gmail.com"
port = 587
# Adjust the THRESHOLD as required.
CPU_THRESHOLD = 10.0 # in percent
MEMORY_THRESHOLD = 10.0 # in percent
# Initialize Docker client
docker_client = docker.from_env()
def monitor_containers():
try:
for container in docker_client.containers.list():
try:
# Fetch container stats
stats = container.stats(stream=False)
# CPU usage calculation
cpu_delta = stats["cpu_stats"]["cpu_usage"]["total_usage"] - stats["precpu_stats"]["cpu_usage"]["total_usage"]
system_delta = stats["cpu_stats"]["system_cpu_usage"] - stats["precpu_stats"]["system_cpu_usage"]
cpu_usage = (cpu_delta / system_delta) * 100 if system_delta > 0 else 0
# Memory usage calculation
memory_usage = stats["memory_stats"]["usage"] / stats["memory_stats"]["limit"] * 100
logging.info(f"Container: {container.name}, CPU: {cpu_usage:.2f}%, Memory: {memory_usage:.2f}%")
# Check thresholds and send alerts
if cpu_usage > CPU_THRESHOLD:
send_email_alert(container.name, "CPU", cpu_usage)
if memory_usage > MEMORY_THRESHOLD:
send_email_alert(container.name, "Memory", memory_usage)
except KeyError as e:
logging.warning(f"Container: {container.name} - Missing key in stats: {e}")
except Exception as e:
logging.error(f"Error monitoring container '{container.name}': {e}")
except Exception as e:
logging.error(f"Failed to monitor containers: {e}")
def send_email_alert(container_name, resource_type, usage):
try:
logging.info("Connecting to SMTP server...")
with smtplib.SMTP(host=host, port=port) as smtp_server:
smtp_server.starttls()
smtp_server.login(user=sender_email, password=password)
logging.info("TLS connection established")
for recipient in recipient_email:
message = MIMEMultipart('alternative')
message['Subject'] = f"High {resource_type} Usage Alert: {container_name}"
message['To'] = recipient['email']
message['From'] = sender_email
body = f"The container '{container_name}' is using {usage:.2f}% {resource_type}. Please investigate."
email_template = f"""\
Greetings {recipient['name']},
{body}
Regards,
Monitoring System
"""
mail_template = MIMEText(email_template, "plain")
message.attach(mail_template)
smtp_server.sendmail(to_addrs=recipient['email'], from_addr=sender_email, msg=message.as_string())
logging.info(f"Email sent to {recipient['email']}")
except smtplib.SMTPAuthenticationError as e:
logging.error(f"Authentication failed. Check your username and password. {e}")
except smtplib.SMTPConnectError as e:
logging.error(f"Failed to connect to the SMTP server. Check your internet connection or server details. {e}")
except smtplib.SMTPException as e:
logging.error(f"An SMTP error occurred: {e}")
except Exception as e:
logging.error(f"Exception occurred: {e}")
if __name__ == "__main__":
logging.info("Starting Docker container monitoring...")
monitor_containers()
logging.info("Monitoring complete.")
Usage
- Run the Script: Execute the script using Python:
python3 docker_monitor.py - Email Alerts:
- The script will send an email alert if any container exceeds the defined resource thresholds.
Example Output
Log Output
2024-12-30 14:23:45 - INFO - Starting Docker container monitoring...
2024-12-30 14:23:46 - INFO - Container: nginx, CPU: 15.32%, Memory: 7.45%
2024-12-30 14:23:46 - INFO - Email sent to recipient@example.com
2024-12-30 14:23:46 - INFO - Monitoring complete.
Email Example
Subject: High CPU Usage Alert: nginx Body:
Greetings Jatin Sharma,
The container 'nginx' is using 15.32% CPU. Please investigate.
Regards,
Monitoring System
Troubleshooting
SMTP Authentication Error:
- Ensure the
sender_emailandpasswordare correct. - Use app-specific passwords for Gmail accounts.
Docker SDK Issues:
Don’t save the python script as docker.py, because it will endup with
circular import error.
- Verify that Docker is installed and running on your system.
- Check if your user has permission to interact with Docker. If not, run the script as a user with appropriate permissions or add your user to the Docker group:
sudo usermod -aG docker $USER
How would you rate this article?
Was this article helpful?