DDAgentForPythonApp

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Datadog Agent Setup for Python App on EC2

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1. Prerequisites

• EC2 instance with Python 3.8+ and a virtual environment (venv) installed.
• Datadog account with API key.
• Security group allowing outbound HTTPS (port 443) for agent reporting.
• Python app installed at /home/<user>/<app-name> (example uses example-app).

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2. Install Datadog Agent

1. Set environment variables for your Datadog API key, site, and environment:

export DD_API_KEY=XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
export DD_SITE="datadoghq.com"   # Use datadoghq.eu for EU, datadoghq.in for India
export DD_ENV=prod

2. Install Datadog Agent v7:

bash -c "$(curl -L https://install.datadoghq.com/scripts/install_script_agent7.sh)"

3. Verify installation:

sudo systemctl status datadog-agent
sudo datadog-agent status

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3. Configure Datadog Agent

1. Edit the main configuration file:

sudo nano /etc/datadog-agent/datadog.yaml

api_key: XXXXXXXXXXXXXXXXXXXXXXXXXXXXXXXX
site: datadoghq.com
tags:
  - env:prod

apm_config:
  enabled: true
  env: prod

2. Restart the agent:

sudo systemctl restart datadog-agent

3. Verify APM listener:

sudo datadog-agent status | grep -A10 "APM Agent"

• Should show listener running on 127.0.0.1:8126.

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4. Python Application Setup (example-app)

/home/ec2-user/example-app/
├── venv/
├── main.py
├── requirements.txt

1. Activate virtual environment and install dependencies:

source /home/ec2-user/example-app/venv/bin/activate
pip install ddtrace uvicorn fastapi

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5. Create Systemd Service for Python App

1. Create the unit file /etc/systemd/system/example-app.service:

[Unit]
Description=Example Python FastAPI Application
After=network.target

[Service]
User=root
Group=root
WorkingDirectory=/home/ec2-user/example-app
Environment=DD_AGENT_HOST=127.0.0.1
Environment=DD_SERVICE=example-app
Environment=DD_ENV=prod
Environment=DD_VERSION=1.0.0
Environment=DD_TRACE_REMOVE_INTEGRATION_SERVICE_NAMES=true
ExecStart=/home/ec2-user/example-app/venv/bin/ddtrace-run /home/ec2-user/example-app/venv/bin/uvicorn main:app --host 0.0.0.0 --port 8000
Restart=always
RestartSec=5
StandardOutput=journal
StandardError=journal

[Install]
WantedBy=multi-user.target

2. Enable and start the service:

sudo systemctl daemon-reload
sudo systemctl enable example-app
sudo systemctl start example-app
sudo journalctl -u example-app -f

ddtrace-run ensures traces from the Python app are sent to the local Datadog Agent. Logs are captured in the systemd journal and can be viewed using journalctl.

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6. Verification

1. Host Metrics:
   • Go to Datadog Dashboard → Host Metrics
   • Verify CPU, memory, disk, and network metrics from the EC2 instance.
2. APM Traces:
   • Go to Datadog APM → Tracing Dashboard
   • Requests to your FastAPI app should appear automatically with traces.
3. Agent Status:
   sudo datadog-agent status
   
   Ensure:
   • Forwarder API key is valid.
   • Core checks (system.cpu, system.mem, etc.) show OK.
   • APM Agent listener is running.

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✅ References

• Datadog Agent Installation for Linux
• Datadog Custom Dashboards
• Datadog APM Tracing