This content originally appeared on DEV Community and was authored by John Ajera
📌 Datadog Agent Debugging Checklist
If your Datadog Agent is running without errors but your host is missing from the Datadog UI, follow this guide to diagnose and resolve the issue efficiently.
1️⃣ Verify Datadog Agent Status
Run the following command to check if the agent is active:
sudo systemctl status datadog-agent
✅ Expected Output:
● datadog-agent.service - Datadog Agent
Loaded: loaded (/lib/systemd/system/datadog-agent.service; enabled; vendor preset: enabled)
Active: active (running) since ...
🚨 If inactive or failed, restart the agent:
sudo systemctl restart datadog-agent
2️⃣ Check Agent Logs for Errors
To review logs for potential issues:
sudo journalctl -u datadog-agent --no-pager --lines=50
✅ Look for messages related to:
- API key authentication failures
- Connection refused errors
- Failure to reach Datadog servers
3️⃣ Verify API Key & Connectivity
Ensure the API key is correctly set:
sudo grep -oP '(?<=api_key: ).*' /etc/datadog-agent/datadog.yaml
Then, test connectivity manually:
sudo curl -v "https://api.datadoghq.com/api/v1/validate?api_key=$(sudo grep -oP '(?<=api_key: ).*' /etc/datadog-agent/datadog.yaml)"
✅ Expected Response (200 OK):
{"valid":true}
🚨 If response is 403 Forbidden or 401 Unauthorized, the API key is incorrect. Verify and update it in /etc/datadog-agent/datadog.yaml.
4️⃣ Check Hostname in Datadog
sudo datadog-agent hostname
✅ Ensure this matches the expected hostname in Datadog UI.
🚨 If incorrect, manually set it in /etc/datadog-agent/datadog.yaml:
hostname: my-hostname
Restart the agent:
sudo systemctl restart datadog-agent
5️⃣ Test Network Connectivity Manually
Instead of datadog-agent check connectivity, manually test connectivity:
curl -v https://app.datadoghq.com
curl -v https://api.datadoghq.com
✅ Expected Output: No Connection refused or Timeout errors.
🚨 If blocked, allow outbound traffic:
sudo ufw allow out to api.datadoghq.com
6️⃣ Verify Datadog Agent is Sending Data
sudo datadog-agent status | grep -A10 "Forwarder"
✅ Look for:
Transactions flushed: successfully: X, errors: 0
🚨 If errors: X appears, the agent is not sending data. Restart it:
sudo systemctl restart datadog-agent
7️⃣ Manually Send a Test Metric
If the agent is running but not visible, manually send a test metric:
sudo datadog-agent telemetry send test.metric 1
✅ Check in Datadog UI → Metrics Explorer and search for test.metric.
📌 Summary of Debugging Steps
| Check | Command | Expected Result | |
|---|---|---|---|
| Agent is running | sudo systemctl status datadog-agent |
Active: running |
|
| Check logs for errors | sudo journalctl -u datadog-agent --no-pager --lines=50 |
No connection/auth errors | |
| Verify API key | sudo grep -oP '(?<=api_key: ).*' /etc/datadog-agent/datadog.yaml |
Matches correct API key | |
| Test Datadog connectivity | curl -v https://api.datadoghq.com |
No network errors | |
| Check hostname | sudo datadog-agent hostname |
Matches expected hostname | |
| Check network reachability | ping api.datadoghq.com |
Successful ping | |
| Ensure metrics are sent | `sudo datadog-agent status | grep -A10 "Forwarder"` | No errors in transactions |
| Manually send a test metric | sudo datadog-agent telemetry send test.metric 1 |
Appears in Datadog UI |
🚀 Follow these steps to ensure your non-containerized host appears in the Datadog UI! Need more help? Drop a comment or reach out! 🚀
This content originally appeared on DEV Community and was authored by John Ajera
John Ajera | Sciencx (2025-02-01T01:23:36+00:00) Datadog Agent Debugging Checklist. Retrieved from https://www.scien.cx/2025/02/01/datadog-agent-debugging-checklist/
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