NerdTools

Fast, free online tools for sysadmins, developers, and nerds.

Server Monitoring

Troubleshooting offline or missing data

If a server looks offline or charts stop updating, work through the checks below.

1. Confirm the last check-in window

The dashboard marks a server as online when it has reported within the last 5 minutes. If the last report is older than that, it is shown as offline.

2. Verify the cron job

The installer creates /etc/cron.d/nerdtools-agent to run every minute. Ensure it exists and that /usr/local/bin/nerdtools-agent is executable.

3. Check the agent log

Failures to post are written to /var/log/nerdtools-agent.log. Look for missing token or network errors.

4. Match host and token

The token is tied to a specific host. The host must match what you registered in the dashboard and can only include letters, numbers, dots, underscores, and dashes.

5. Confirm the endpoint URL

In /etc/nerdtools-agent.conf, ensure NERDTOOLS_ENDPOINT points to your NerdTools domain at /server-agent.php.

Back to all articles