Troubleshooting Grafana Prometheus Integration 404 Error And Build Info Issues

by StackCamp Team 79 views

Integrating Grafana with Prometheus is crucial for monitoring and visualizing metrics from various applications and systems. In this article, we will address a common issue encountered while setting up a Prometheus datasource in Grafana, specifically when trying to monitor a crowdsec-mikrotik-bouncer instance. The user is facing a 404 Not Found error and warning messages in the Grafana logs, indicating problems with the Prometheus API and build information retrieval. This comprehensive guide will walk you through the troubleshooting steps, potential causes, and solutions to resolve this integration challenge. Understanding these steps ensures you can effectively monitor your systems using Grafana and Prometheus.

Understanding the Problem

The core issue revolves around Grafana's inability to connect to the Prometheus endpoint exposed by the crowdsec-mikrotik-bouncer. The user attempted to add the metrics page to Grafana using the URLs http://crowdsec-mikrotik-bouncer:2112/metrics and http://crowdsec-mikrotik-bouncer:2112, but encountered a 404 Not Found error. Further investigation into the Grafana logs revealed warning messages indicating failures in retrieving Prometheus heuristics and build information. These messages suggest a deeper problem than just a simple URL mismatch. Let's delve into the possible reasons for these errors and how to address them.

Analyzing the Grafana Logs

To effectively troubleshoot, it's essential to dissect the Grafana logs provided by the user. The logs contain valuable clues about the nature of the problem. Here's a breakdown of the relevant log entries:

{
  "logger": "tsdb.prometheus",
  "endpoint": "checkHealth",
  "pluginId": "prometheus",
  "dsName": "prometheus-crowdsec-mikrotik-bouncer",
  "dsUID": "cer0ho58l8kqod",
  "uname": "admin",
  "t": "2025-07-06T11:20:46.379130566+02:00",
  "level": "warn",
  "msg": "Failed to get prometheus heuristics",
  "err": "failed to get buildinfo: no build info"
}

{
  "logger": "tsdb.prometheus",
  "endpoint": "checkHealth",
  "pluginId": "prometheus",
  "dsName": "prometheus-crowdsec-mikrotik-bouncer",
  "dsUID": "cer0ho58l8kqod",
  "uname": "admin",
  "t": "2025-07-06T11:20:46.37911128+02:00",
  "level": "warn",
  "msg": "Failed to get prometheus buildinfo",
  "err": "no build info"
}

These logs indicate that Grafana's Prometheus datasource plugin (pluginId: prometheus) failed to retrieve both heuristics and build information from the specified endpoint. The error message no build info suggests that the /metrics endpoint might not be correctly exposing the Prometheus metrics, or there could be an issue with the Prometheus server itself. The 404 Not Found error further supports the idea that the endpoint is either not accessible or not correctly configured. Understanding these errors is the first step in diagnosing and resolving the issue. Let’s explore potential causes and solutions in the subsequent sections.

Potential Causes and Solutions

1. Incorrect Prometheus Endpoint

One of the most common causes of a 404 Not Found error is an incorrect Prometheus endpoint. It is crucial to ensure that the URL specified in Grafana matches the actual endpoint exposed by the crowdsec-mikrotik-bouncer. Double-check the URL (http://crowdsec-mikrotik-bouncer:2112/metrics) for typos and ensure that the port (2112) is the correct one. If the crowdsec-mikrotik-bouncer is running in a containerized environment (e.g., Docker), the hostname might need to be adjusted to the container's name or IP address within the network.

  • Solution: Verify the correct endpoint by accessing it directly via a web browser or curl. For example, use the command curl http://crowdsec-mikrotik-bouncer:2112/metrics from the Grafana server to see if it returns Prometheus metrics. If you get a 404 error here as well, the issue lies with the endpoint configuration itself, not Grafana.

2. Network Connectivity Issues

Network connectivity problems can prevent Grafana from accessing the Prometheus endpoint. Ensure that Grafana and the crowdsec-mikrotik-bouncer can communicate with each other over the network. Firewalls, network policies, or container networking configurations might be blocking the connection. Check if there are any firewalls between Grafana and the crowdsec-mikrotik-bouncer that might be blocking traffic on port 2112. Similarly, if running in a containerized environment, verify that the containers are on the same network or that appropriate port mappings are in place.

  • Solution: Use tools like ping or traceroute to check basic network connectivity between Grafana and the crowdsec-mikrotik-bouncer. If running in Docker, ensure that the containers are part of the same network or have proper port mappings configured using the -p flag. For instance, docker run -p 3000:3000 grafana/grafana would map port 3000 on the host to port 3000 in the Grafana container. You can also use docker inspect <container_id> to examine the network settings of the containers.

3. Prometheus Server Misconfiguration

The crowdsec-mikrotik-bouncer might not be correctly exposing Prometheus metrics. Ensure that the Prometheus server is running correctly and that the /metrics endpoint is properly configured to serve metrics. A misconfigured Prometheus server will not expose the necessary metrics, leading to Grafana's inability to retrieve build information and heuristics. This could be due to incorrect configuration files, missing scrape jobs, or other internal errors within the Prometheus setup.

  • Solution: Check the configuration files of the crowdsec-mikrotik-bouncer to ensure that Prometheus metrics are being exposed. Look for settings related to the metrics endpoint and confirm that they are correctly set. Also, inspect the Prometheus server logs for any errors or warnings that might indicate a problem with the metrics collection or exposure. You can verify the Prometheus configuration by checking the prometheus.yml file for the necessary scrape jobs and endpoint settings. Common issues include incorrect target configurations or misconfigured authentication settings.

4. Authentication and Authorization Issues

If the Prometheus endpoint requires authentication, Grafana needs to be configured with the correct credentials. Prometheus endpoints can be protected with authentication mechanisms such as Basic Auth or TLS. If the crowdsec-mikrotik-bouncer requires authentication, ensure that Grafana is configured with the necessary credentials to access the metrics. Failing to provide the correct credentials will result in a 401 Unauthorized or similar error, though in this case, the 404 error suggests a different underlying issue.

  • Solution: Check if the Prometheus endpoint requires authentication by attempting to access it via curl with the -u flag for username and password (e.g., curl -u user:password http://crowdsec-mikrotik-bouncer:2112/metrics). If authentication is required, configure the Prometheus datasource in Grafana with the appropriate credentials. This can be done in the Grafana datasource settings under the HTTP settings section, where you can specify Basic Auth details or other authentication methods.

5. Version Incompatibility

In rare cases, incompatibility issues between Grafana and Prometheus versions can cause problems. Ensure that the versions of Grafana and Prometheus you are using are compatible. While version incompatibility is less common, it can sometimes lead to unexpected issues. Check the official documentation for both Grafana and Prometheus to verify compatibility guidelines.

  • Solution: Review the release notes and compatibility matrices for both Grafana and Prometheus. Consider upgrading or downgrading either Grafana or Prometheus to a compatible version if necessary. It's often recommended to use the latest stable versions to avoid known issues and benefit from the latest features and bug fixes.

6. DNS Resolution Problems

DNS resolution issues can prevent Grafana from resolving the hostname of the crowdsec-mikrotik-bouncer. If Grafana is unable to resolve the hostname crowdsec-mikrotik-bouncer, it will not be able to connect to the Prometheus endpoint. This issue is particularly relevant in containerized environments where DNS resolution might be managed internally.

  • Solution: Verify that Grafana can resolve the hostname by using tools like nslookup or dig from the Grafana server. If DNS resolution is failing, ensure that the DNS settings on the Grafana server are correctly configured. In a Docker environment, ensure that the containers are on a network that provides DNS resolution, or use Docker's built-in DNS services by referencing containers by their service names in a Docker Compose file.

Step-by-Step Troubleshooting Guide

To systematically troubleshoot the issue, follow these steps:

  1. Verify the Prometheus Endpoint:

    • Use curl http://crowdsec-mikrotik-bouncer:2112/metrics from the Grafana server to check if the endpoint is accessible and returns metrics.
    • If you receive a 404 error, the issue is with the crowdsec-mikrotik-bouncer or its configuration.

  2. Check Network Connectivity:

    • Use ping crowdsec-mikrotik-bouncer from the Grafana server to check basic network connectivity.
    • If the ping fails, investigate firewall rules, network policies, and container network configurations.

  3. Inspect Prometheus Configuration:

    • Examine the crowdsec-mikrotik-bouncer configuration files to ensure Prometheus metrics are being exposed correctly.
    • Check Prometheus server logs for any errors or warnings.

  4. Review Authentication Settings:

    • If the Prometheus endpoint requires authentication, configure the Grafana datasource with the correct credentials.

  5. Check DNS Resolution:

    • Use nslookup crowdsec-mikrotik-bouncer from the Grafana server to verify DNS resolution.
    • Ensure the Grafana server's DNS settings are correctly configured.

  6. Restart Services:

    • Restart the crowdsec-mikrotik-bouncer, Prometheus, and Grafana services to ensure that any configuration changes are applied.

  7. Review Grafana Logs:

    • Continuously monitor the Grafana logs for any new error messages or warnings.

Practical Examples

Let’s illustrate some of the solutions with practical examples.

Example 1: Verifying Endpoint with curl

Open a terminal on the Grafana server and run:

curl http://crowdsec-mikrotik-bouncer:2112/metrics

If the output is Prometheus metrics, the endpoint is correctly configured. If you receive a 404 Not Found error, the issue lies with the endpoint configuration on the crowdsec-mikrotik-bouncer side.

Example 2: Checking Network Connectivity with ping

Run the following command on the Grafana server:

ping crowdsec-mikrotik-bouncer

If the ping is successful, network connectivity is established. If the ping fails, investigate firewall rules and network configurations.

Example 3: Configuring Prometheus Datasource in Grafana

  1. In Grafana, navigate to Configuration > Data Sources.
  2. Click Add data source and select Prometheus.
  3. Enter the Prometheus URL (http://crowdsec-mikrotik-bouncer:2112).
  4. If authentication is required, configure the HTTP Auth settings.
  5. Click Save & Test to verify the connection.

Best Practices for Grafana and Prometheus Integration

To ensure a smooth integration between Grafana and Prometheus, consider these best practices:

  • Regularly Monitor Logs: Keep an eye on the logs for both Grafana and Prometheus to identify potential issues early.
  • Use Descriptive Datasource Names: Give your datasources descriptive names in Grafana to easily identify them.
  • Implement Alerting: Set up alerts in Grafana to notify you of critical issues based on Prometheus metrics.
  • Secure Your Endpoints: Protect your Prometheus endpoints with authentication and TLS to prevent unauthorized access.
  • Keep Software Updated: Regularly update Grafana and Prometheus to the latest stable versions to benefit from bug fixes and new features.

Conclusion

Troubleshooting Grafana Prometheus datasource integration issues requires a systematic approach. By understanding the potential causes, such as incorrect endpoints, network connectivity problems, Prometheus misconfigurations, authentication issues, version incompatibilities, and DNS resolution failures, you can effectively diagnose and resolve the problem. Following the step-by-step troubleshooting guide and implementing the best practices outlined in this article will help you ensure a robust and reliable monitoring setup. Remember, a well-integrated Grafana and Prometheus system is crucial for gaining insights into your application's performance and health, enabling proactive issue resolution and optimal system management.

By applying these solutions and practices, you can overcome the challenges of integrating Grafana with Prometheus and leverage the powerful monitoring capabilities they offer together. This ensures that you have a clear view of your system's health and performance, enabling you to address issues proactively and maintain optimal operational efficiency.