Oh No! “There was an error returned querying the Prometheus API” in Grafana when creating new Prometheus Datasource?

Don’t panic! This error message might seem daunting, but trust us, we’ve got you covered. In this article, we’ll guide you through the troubleshooting process to identify and resolve the issue. By the end of this, you’ll be creating new Prometheus datasources in Grafana like a pro!

What is Prometheus, and why do I need it in Grafana?

Prometheus is an open-source monitoring system and time-series database. It’s an incredibly powerful tool for monitoring and alerting your applications, allowing you to collect metrics and query them in a flexible and efficient way. Grafana, on the other hand, is a visualization platform that enables you to create dashboards and graphs to visualize your metrics. The two are a match made in heaven, and that’s why you need Prometheus in Grafana!

The Error: “There was an error returned querying the Prometheus API”

When creating a new Prometheus datasource in Grafana, you might encounter this error message:

 Error: There was an error returned querying the Prometheus API: request failed with status code 400

Or, in some cases:

 Error: There was an error returned querying the Prometheus API: dial tcp :9090: connect: connection refused

Don’t worry; we’ll help you diagnose the issue and get your Prometheus datasource up and running!

Step 1: Check the Basics

Before we dive into the nitty-gritty, let’s cover the basics:

• Ensure your Prometheus server is running and accessible. Check the server’s status using curl http://localhost:9090 or wget http://localhost:9090. If the server is not running, start it up!

• Verify that your Prometheus server is configured correctly. Check the configuration file (prometheus.yml) to ensure it’s properly set up. You can refer to the official Prometheus documentation for configuration guidelines.

• Double-check your Grafana and Prometheus versions. Make sure they’re compatible and up-to-date. You can check the versions in the Grafana UI (Settings > Server > Version) or by running grafana-server --version and prometheus --version respectively.

Step 2: Check the Prometheus API

Let’s investigate the Prometheus API:

curl -v http://localhost:9090/api/v1/query?query=up

This command queries the up metric, which should return a simple response indicating if the Prometheus server is up or down.

• If the API returns a successful response (200 OK), it’s a good sign! The issue might be specific to Grafana. Proceed to the next step.

• If the API returns an error (400, 404, or 500), there might be a problem with your Prometheus configuration or server. Check the Prometheus logs for errors and troubleshoot accordingly.

Step 3: Inspect the Grafana Configuration

Now, let’s examine the Grafana configuration:

grafana-server --config file-path

file-path WITH THE PATH TO YOUR GRAFANA CONFIGURATION FILE_

Check the following settings:

• Ensure the datasources section is correctly configured. Verify the Prometheus datasource settings, including the URL, username, and password.

• Check the http_config section. If you’re using a proxy or have specific HTTP settings, ensure they’re correctly configured.

Step 4: Verify Firewall and Network Settings

Firewalls and network settings can be the culprit:

sudo ufw status

ufw allow 9090 to allow incoming traffic on the port._

Also, verify your network settings:

• Check your Prometheus server’s network IP and ensure it’s accessible from the Grafana server.

• Verify that there are no network issues or connectivity problems between the Grafana and Prometheus servers.

Step 5: Check the Prometheus Datasource Configuration in Grafana

Let’s review the Prometheus datasource configuration in Grafana:

grafana-server --datasource-configuration

Step 6: Enable Debug Logging in Grafana

Enabling debug logging can provide valuable insights:

grafana-server --debug

Common Issues and Solutions

We’ve seen it all! Here are some common issues and their solutions:

Issue	Solution
Prometheus server not running	Start the Prometheus server or ensure it’s running properly.
Prometheus configuration issue	Check the Prometheus configuration file (prometheus.yml) and ensure it’s correctly configured.
Grafana and Prometheus version mismatch	Ensure both Grafana and Prometheus are running compatible versions. Update either or both to the latest version.
Firewall or network issues	Verify firewall settings and ensure the Prometheus port is allowed. Check network connectivity between the Grafana and Prometheus servers.
Misconfigured Prometheus datasource in Grafana	Check the Prometheus datasource configuration in Grafana and ensure it’s correctly set up.

Conclusion

That’s it! By following these steps, you should be able to identify and resolve the “There was an error returned querying the Prometheus API” issue in Grafana. Remember to stay calm, be patient, and methodically troubleshoot the problem. If you’re still stuck, feel free to reach out to the Grafana or Prometheus communities for further assistance.

Happy monitoring and happy troubleshooting!

Frequently Asked Question

Hey there, Grafana enthusiasts! Have you ever encountered the dreaded “There was an error returned querying the Prometheus API” error when creating a new Prometheus data source in Grafana? Don’t sweat, we’ve got you covered! Here are the top 5 FAQs to help you troubleshoot this issue like a pro: