Prometheus is a favored open-source monitoring system that collects, stores, and queries metrics from various sources. In Prometheus, an exporter is a component that collects and exposes metrics in a format Prometheus can scrape.

The Prometheus Blackbox Exporter is designed to monitor “black box” systems with internal workings that are not accessible by Prometheus. It sends HTTP, TCP, and ICMP requests to the external systems and measures their response times and statuses.

Prometheus Blackbox Exporter is highly configurable and customizable. Users can define various endpoints, such as HTTP endpoints with specific headers, TCP endpoints with custom payloads, and ICMP endpoints with exact payload sizes. Additionally, users can define timeouts, TLS settings, and authentication options for each endpoint. It can be used independently or with other Prometheus exporters and can help monitor complex systems with multiple dependencies when used with other exporters.

This article will explain Prometheus Blackbox Exporter in detail, including its benefits, how it works, limitations, nine essential best practices, and a practical walkthrough covering how to install Prometheus Blackbox Exporter.

Summary of key Prometheus Blackbox Exporter concepts

Prometheus Blackbox Exporter can probe external endpoints using protocols such as HTTP, HTTPS, ICMP, DNS, and TCP to collect metrics about their health and responsiveness. Prometheus can then use the metrics for alerting, graphing, and analysis. The table below summarizes nine key concepts related to the benefits of Prometheus Blackbox Exporter for organizations that need to monitor external systems and services.

How does Prometheus Blackbox Exporter work?

Prometheus Blackbox Exporter is a standalone application that runs alongside a Prometheus server. The exporter is written in Go, a compiled language that provides high-performance and efficient execution. It is modular and allows for extensions to add new protocol and endpoint support.

Prometheus Blackbox Exporter works by executing probes against endpoints and returning metrics based on the results of those probes. For example, the HTTP probe supports various options, such as setting a custom user agent string, specifying custom headers, and setting a timeout for the request. The exporter also supports authentication options for HTTP and HTTPS probes, allowing you to specify credentials for basic authentication or a bearer token for token-based authentication. It also provides several advanced features, such as caching probe results, configuring timeouts, and retries for probes. These features help ensure the exporter is efficient and reliable, even in complex and dynamic environments.

In addition to its core functionality, Prometheus Blackbox Exporter provides a robust set of metrics to observe the health and performance of your endpoints. These metrics include each probe's response time, the response status codes, and the probes' overall success rate.

Metrics

Prometheus Blackbox Exporter can collect a wide range of metrics to monitor the availability and performance of networked services. Some of the commonly used metrics that Prometheus Blackbox Exporter can collect include:

1. Uptime: This metric measures the availability and uptime of a service or system. It provides information on how long the service has been up and running without experiencing any downtime.
2. Latency: Latency is a critical metric that measures the time taken for a service to respond to a request. Prometheus Blackbox Exporter can measure the latency of a service by sending requests and measuring the response time, helping to identify any performance degradation or delays.
3. Response Codes: Prometheus Blackbox Exporter can collect HTTP response codes, such as 200 OK, 404 Not Found and 500 Internal Server Error, to provide information on the status of the service or system being probed. This can help detect any issues or errors in the service's responses.
4. DNS Resolution Time: Prometheus Blackbox Exporter can measure the time taken to resolve DNS queries, providing insights into the performance of DNS resolution for a given service or system.
5. SSL/TLS Handshake Time: If the probed service uses SSL/TLS encryption, Prometheus Blackbox Exporter can measure the time taken for the SSL/TLS handshake, providing information on the performance and security of the encryption process.
6. Network Connectivity: Prometheus Blackbox Exporter can monitor network connectivity by checking if a service is reachable and providing information on network availability and potential connectivity issues.
7. Content Validation: Prometheus Blackbox Exporter can validate the content of a response from a service to ensure that it matches expected patterns or values, verifying the correctness of responses from a service.
8. Custom Metrics: Prometheus Blackbox Exporter also supports custom metrics besides the built-in metrics. Users can define their metrics based on their specific monitoring requirements, allowing for flexibility in monitoring and alerting.

The exact metrics that can be collected in any specific implementation depend on the configuration and probing parameters set up for each target. By collecting and analyzing these metrics, Prometheus Blackbox Exporter provides valuable insights into networked services' health and performance, helping to identify and resolve issues proactively.

Use Cases for Prometheus Blackbox Exporter

The Prometheus Blackbox Exporter has a variety of use cases. This section explores eight typical use cases in detail.

Probing external services and endpoints

Blackbox Exporter allows for monitoring the availability and performance of external services or endpoints by probing them using protocols such as HTTP, HTTPS, ICMP, DNS, TCP, and more. This can include APIs, websites, databases, DNS servers, or any other critical services essential for an application's operation. By regularly probing these external services, Blackbox Exporter can provide insights into their availability, responsiveness, and performance, allowing operators to detect and address issues promptly.

Proactive alerting and incident management

Blackbox Exporter can send alerts to Prometheus when a probed endpoint becomes unavailable, responds with errors, or does not meet certain performance thresholds. This enables operators to proactively detect and respond to issues before they impact the availability or performance of their applications. With alerting rules and integration with incident management tools, Blackbox Exporter can facilitate incident detection, triage, and resolution, improving the overall reliability of monitored services.

Monitoring multi-cloud or multi-environment setups

Many organizations deploy their applications across multiple clouds or environments for redundancy, scalability, or geo-distribution. Blackbox Exporter can monitor the availability and performance of endpoints across different clouds, regions, or environments, providing insights into the health of the overall distributed setup. This can help detect cross-cloud or cross-environment issues and enable a timely resolution to ensure the reliability of the application across different deployment scenarios.

Network monitoring and troubleshooting

Prometheus Blackbox Exporter can be used to monitor the network health and connectivity between different components or nodes in a distributed system. It can probe endpoints using protocols such as ICMP, TCP, or DNS to check for network connectivity, latency, and packet loss, helping identify networking issues such as network partitions, misconfigurations, or failures and facilitating troubleshooting to resolve network-related incidents.

Monitoring external dependencies and third-party services

Applications often depend on external services or APIs, such as databases, caching systems, message brokers, or third-party APIs. Prometheus Blackbox Exporter can monitor the health and performance of these dependencies by probing their endpoints, checking for expected responses, and measuring response times. This can help identify issues with external services that impact application performance or availability and enable timely resolution.

Security monitoring and vulnerability detection

Prometheus Blackbox Exporter can monitor endpoints' security by checking for expected responses, verifying SSL/TLS certificates, or scanning for vulnerabilities. It can also be used to detect potential security breaches by probing for unauthorized or unexpected endpoints. This can help ensure the security of the monitored services and proactively detect security risks or vulnerabilities.

Custom monitoring scenarios

Prometheus Blackbox Exporter is highly flexible and extensible, allowing users to define custom probes and configure different types of targets. This makes it adaptable to monitor various scenarios, such as custom APIs, third-party services, or legacy systems that may not have built-in monitoring capabilities. Users can define their probes or use existing third-party probes to monitor their specific use cases, enabling tailored monitoring solutions.

Monitoring DNS health and performance

Prometheus Blackbox Exporter provides DNS-specific probes that can be used to monitor the health and performance of DNS servers. It can perform DNS resolution, measure response times, and check for DNSSEC validation, providing insights into the health and performance of DNS infrastructure.

Limitations of Prometheus Blackbox Exporter

While Prometheus Blackbox Exporter offers many benefits for monitoring “blackbox” systems, like any tool, it also has limitations. The sections below explore six limitations of Prometheus Blackbox Exporter.

Protocol support

Prometheus Blackbox Exporter supports monitoring a wide range of network protocols, including HTTP, HTTPS, ICMP, TCP, and DNS. However, it may not support all protocols and may not have full support for all features of the protocols it does support. For example, it may be unable to monitor complex protocols with dynamic payloads or those requiring authentication beyond basic authentication. This means there may be limitations in the applications or systems that can be effectively monitored using the Blackbox Exporter.

Lack of application-specific metrics

Prometheus Blackbox Exporter provides basic metrics such as response time, status code, and DNS resolution time, which are helpful for basic health checks of a networked service. However, it does not provide application-specific metrics that can give insights into an application's internal behavior or performance. For example, it may not capture metrics such as CPU usage, memory consumption, or database query latency, which are critical for understanding the performance and health of an application. This limitation can make performing in-depth monitoring and troubleshooting of complex applications challenging.

Scalability and resource utilization

The Prometheus Blackbox Exporter can generate a decent amount of network traffic when performing active probing of targets, which can impact network performance and scalability. Additionally, it requires system resources such as CPU, memory, and disk space to store and process the collected metrics. Depending on the complexity and scale of the monitoring setup, the Blackbox Exporter may consume significant resources, which can impact the overall performance and scalability of the monitoring solution. This limitation should be considered when planning the deployment of the Prometheus Blackbox Exporter in large-scale environments.

Security concerns

Prometheus Blackbox Exporter performs active probing of targets by sending requests and collecting responses, which can raise security concerns. For example, sending unauthenticated requests to external systems or services may result in unintended consequences or security vulnerabilities. Additionally, Prometheus Blackbox Exporter may store sensitive data such as URLs, usernames, and passwords in its configuration or metrics, posing a security risk if not handled properly. Administrators should follow the best practices for securing sensitive information and ensuring that only authorized targets are probed by the exporter.

Limited alerting capabilities

Prometheus Blackbox Exporter can generate alerts based on metrics thresholds, but it has limited alerting capabilities compared to the core Prometheus server. For example, it may not support advanced alerting features such as aggregation or correlation of multiple metrics, complex alerting rules, or custom notification actions. Implementing sophisticated alerting and notification workflows for complex monitoring setups makes it challenging to implement them, requiring additional tools or workarounds to achieve desired alerting functionality.

Lack of long-term data storage

Prometheus Blackbox Exporter needs support for long-term data storage for use cases like historical analysis and to satisfy compliance requirements. To support these use cases, users may need to configure external storage to address this issue.

Nine essential Prometheus Blackbox Exporter best practices

Prometheus Blackbox Exporter is a powerful tool that monitors and probes networked services to ensure their availability and performance. When used appropriately, it can provide valuable insights into the health and performance of your systems. Here are some best practices to make the most out of Prometheus Blackbox Exporter.

Define clear monitoring objectives

Before implementing Prometheus Blackbox Exporter, clearly define your monitoring objectives. What services or systems do you want to monitor? What are the critical metrics that you need to collect? A clear understanding of your monitoring goals will help you configure the Blackbox Exporter effectively and ensure that you collect the right metrics for your specific use case.

Select appropriate probing targets

Carefully select the targets you want to probe using the Blackbox Exporter. Consider the criticality of the services or systems being probed and the impact of the probing activity on their performance. Avoid overloading your targets with excessive probing requests that may affect their regular operation. Also, ensure you have proper authorization and permissions to probe the targets to avoid security concerns.

Customize probe configuration

Prometheus Blackbox Exporter allows you to configure various parameters for probing, such as timeouts, intervals, and retries. Customize these parameters based on the characteristics of your systems and the network environment. For example, set appropriate timeouts and retries based on the expected response times of your services to avoid false positives or negatives in your monitoring alerts.

Use target labels effectively

Utilize target labels in Prometheus Blackbox Exporter to provide meaningful metadata for your probes. Target labels can help you identify and group your probed targets, making filtering and aggregating metrics in Prometheus easier. Use labels to provide relevant information, such as service name, environment, or location, which can be helpful for troubleshooting and analysis.

Enable alerting and notification

Configure Prometheus alerts and notification rules based on the metrics collected by the Blackbox Exporter. Set appropriate threshold values for metrics to trigger alerts when they exceed or fall below predefined limits. Define alerting rules aligning with your monitoring objectives and notify the proper stakeholders when issues arise to detect and resolve system anomalies or incidents quickly.

Monitor and optimize resource utilization

Keep an eye on the resource utilization of your Prometheus Blackbox Exporter instance. Optimize the resource configuration of the Blackbox Exporter based on the scale and complexity of your monitoring environment to ensure efficient resource utilization. Monitor CPU, memory, and disk usage to ensure that the Blackbox Exporter does not impact the performance and scalability of your overall monitoring setup.

Secure configuration

Avoid storing sensitive information such as usernames, passwords, or API keys in plain text within the configuration. Utilize secure mechanisms such as environment variables, secret stores, or configuration management tools to manage sensitive information securely. Restrict access to the Blackbox Exporter configuration to authorized personnel only.

Regularly review and update monitoring setup

Monitoring requirements and environments change over time, so reviewing and updating your Prometheus Blackbox Exporter setup is essential. Periodically review your monitoring objectives, metrics, alerting rules, and configurations to ensure they are still relevant and practical. Keep the Blackbox Exporter version up to date with the latest releases to benefit from bug fixes, performance improvements, and new features.

Customizing alert routing and escalation policies

You can configure custom alert routing and escalation policies based on the type and severity of the alerts received from Prometheus using tools like Squadcast. For example, you can route alerts to specific teams or individuals based on the service or seriousness of the incident. Incident responders can collaborate in real-time using Squadcast's incident response features, such as incident annotations, status updates, and team chats.

When an alert is triggered and sent to Squadcast, it creates an incident in Squadcast's incident management dashboard. Squadcast allows responders to update the incident status and resolution details upon resolution of the incident. This information can also be automatically sent back to Prometheus to update the alert status, acknowledging that the incident has been resolved. By improving the quality of data and collaboration involved in incident response, integrating Prometheus with tools like Squadcast can help teams meet or exceed SLAs and SLOs.

How to install Prometheus Blackbox Exporter

This section is a walkthrough of the installation steps for Prometheus Blackbox Exporter on Linux.

Prerequisites

Before installing Prometheus Blackbox Exporter, you need to ensure that your system meets the following requirements:

• A Linux-based operating system (Ubuntu, CentOS, Debian or other distribution)
• A user account with sudo privileges
• Prometheus server installed and running
• Basic knowledge of the terminal/command line

Download Prometheus Blackbox Exporter

You can download the latest version of Prometheus Blackbox Exporter from the official Prometheus Github repository. To download the exporter, use the following command:

$ wget 
https://github.com/prometheus/blackbox_exporter/releases/download/v0.19.0/blackbox_exporter-0.19.0.linux-amd64.tar.gz

This will download the tarball of the Prometheus Blackbox Exporter to your current working directory.

Extract the files

Once the download is complete, you must extract the files from the tarball and move the files to the appropriate location. We will transfer the files to /opt/blackbox_exporter. To do this, use the following command

$ tar -xvf blackbox_exporter-0.19.0.linux-amd64.tar.gz
$ sudo mv blackbox_exporter-0.19.0.linux-amd64 /opt/blackbox_exporter

Create a service file

You must create a service file to manage the Prometheus Blackbox Exporter service.

$ sudo nano /etc/systemd/system/blackbox_exporter.service

Then, add the following lines to the file.

[Unit]
Description=Prometheus Blackbox Exporter
Wants=network-online.target
After=network-online.target

[Service]
User=nobody
Group=nogroup
Type=simple
ExecStart=/opt/blackbox_exporter/blackbox_exporter

[Install]
WantedBy=multi-user.target

Restart the systemd service.

$ sudo systemctl daemon-reload

Start the Prometheus Blackbox Exporter service and enable the service to start automatically at boot time.

$ sudo systemctl start blackbox_exporter
$ sudo systemctl enable blackbox_exporter

Configure Prometheus

Finally, you must configure Prometheus to scrape the metrics from the Blackbox Exporter. To do this, add the following lines to your Prometheus configuration file under the “scrape_configs” section:

scrape_configs:
- job_name: 'blackbox'
  metrics_path: /probe
  params:
    module: [http_2xx]
  static_configs:
    - targets:
      - https://example.com
      - http://example.net:808

In this example, the job name is blackbox, and it specifies the metrics endpoint path and the module to use for the probe. The targets section lists the URLs to monitor. You can access the target page by visiting the Prometheus web interface, which is typically available at http://localhost:9090.

Conclusion

In today's digital world, where services are increasingly complex and distributed, monitoring external services is becoming more critical than ever. Prometheus Blackbox Exporter is essential for any organization that monitors external services such as HTTP, DNS, TCP, ICMP, etc. With Prometheus Blackbox Exporter, you can easily collect metrics about the health and performance of your external services and integrate them into your monitoring system. This enables you to proactively identify and resolve issues before they become critical, improving service uptime and user satisfaction. Using Prometheus Blackbox Exporter lets you stay on top of your external service health and ensure your users have a seamless experience with your applications.

Prometheus Blackbox Exporter is easy to install and configure and seamlessly integrates with Prometheus, a popular open-source monitoring solution. By using Prometheus Blackbox Exporter in conjunction with Prometheus, you can get a complete picture of the health and performance of your entire internal and external infrastructure.

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