Understanding Prometheus Pushgateway with Examples

In this article, we’ll explore Prometheus Pushgateway, an essential tool for managing short-lived job metrics in Prometheus monitoring setups. We’ll uncover its role in ensuring comprehensive visibility into dynamic environments.

Understanding Prometheus Pushgateway with Examples 1

What is Prometheus?

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Prometheus is an open-source monitoring and alerting toolkit designed for reliability and scalability in modern, dynamic environments. Developed by the Cloud Native Computing Foundation, Prometheus excels at collecting and storing time-series data, allowing users to gain valuable insights into the performance and health of their applications and infrastructure.

With its powerful query language and support for multi-dimensional data, Prometheus has become a popular choice for monitoring systems within cloud-native ecosystem.

What is Prometheus Pushgateway?

Prometheus Pushgateway serves as a bridge for jobs that cannot be scraped directly by Prometheus due to their ephemeral nature. It allows these jobs to push their metrics to a metrics cache, enabling Prometheus to collect them.

For example, consider a batch job that runs periodically to process data and generate metrics. Since the job’s lifecycle is short-lived, it may not have a long-lived endpoint for Prometheus to scrape. In such cases, the job can push its metrics to Pushgateway, which stores them temporarily. Prometheus then scrapes the metrics from Pushgateway, ensuring they are collected and analyzed despite the job’s transient nature.

Architecture of Prometheus Pushgateway

Understanding Prometheus Pushgateway with Examples 2
  1. Pushgateway Server:
    • The Pushgateway server is a standalone component that exposes an HTTP endpoint.
    • This endpoint is where jobs or services can push their metrics data.
  2. Metrics Cache:
    • Pushgateway acts as a metrics cache, storing metrics pushed by jobs or services until they are scraped by Prometheus.
    • This caching mechanism ensures that Prometheus can collect metrics even from short-lived or batch jobs.
  3. HTTP Interface:
    • Pushgateway provides a simple HTTP interface that allows jobs or services to push metrics using HTTP POST requests.
    • Metrics are typically pushed with a job name and optional grouping labels.
  4. Temporary Storage:
    • Pushgateway stores metrics temporarily, allowing Prometheus to scrape them until they are overwritten or expire.
    • Metrics are associated with specific jobs, allowing Prometheus to differentiate between different types of metrics.
  5. Expiry Mechanism:
    • Pushgateway provides an expiry mechanism for metrics to prevent the accumulation of stale data.
    • Metrics can be configured with a TTL (time-to-live), after which they are automatically deleted from the Pushgateway.
  6. Prometheus Scraping:
    • Prometheus scrapes metrics from the Pushgateway’s HTTP endpoint at regular intervals.
    • During scraping, Prometheus collects metrics pushed by jobs or services and integrates them into its time series database.
  7. Labeling Support:
    • Pushgateway supports labeling of metrics, allowing jobs or services to include additional metadata with their metrics.
    • Labels help in organizing and querying metrics effectively within Prometheus.
  8. High Availability Considerations:
    • To ensure high availability, it’s recommended to deploy Pushgateway in a redundant configuration with proper monitoring and alerting mechanisms.

In summary, Prometheus Pushgateway acts as a bridge between short-lived jobs or services and Prometheus, providing a mechanism for pushing metrics over HTTP.

Use-Cases of Prometheus Pushgateway

  1. Short-lived or Batch Jobs: Pushgateway is ideal for collecting metrics from short-lived or batch-oriented jobs that don’t have long-lived endpoints for scraping.
  2. Ephemeral Workloads: In dynamic environments like container orchestration platforms (e.g., Kubernetes), where instances of services can be created and destroyed frequently, Pushgateway provides a mechanism for collecting metrics from ephemeral workloads.
  3. Multi-step Workflows: Pushgateway facilitates the aggregation of metrics from multi-step workflows or processes, allowing different stages of a process to push their metrics for centralized monitoring.
  4. External Service Monitoring: It can be used to monitor metrics from external services or systems that are not directly scrapeable by Prometheus, such as services running in isolated networks or behind firewalls.
  5. Batch Processing Systems: Pushgateway is commonly used to monitor metrics from batch processing systems where jobs run periodically and need to push their metrics upon completion.
  6. Dynamic Environments: Any scenario where the number of targets or instances is highly dynamic and configuring Prometheus to scrape them individually is not feasible.

Prometheus Pushgateway Benefits and Challenges

Benefits:

  1. Support for Short-lived Jobs: Allows short-lived or batch jobs to push their metrics to Prometheus, ensuring that metrics are collected even from ephemeral workloads.
  2. Dynamic Environment Compatibility: Compatible with dynamic environments like container orchestration platforms, where instances can be created and destroyed frequently.
  3. Centralized Metric Collection: Facilitates centralized collection of metrics from various sources, including multi-step workflows and external services, for unified monitoring.
  4. Simplified Monitoring Setup: Simplifies monitoring setup by providing a mechanism for targets without long-lived endpoints to expose their metrics to Prometheus.

Challenges:

  1. Increased Complexity: Introduces additional complexity to the monitoring infrastructure compared to traditional scraping methods, potentially requiring more careful management and monitoring.
  2. Risk of Stale Data: Metrics pushed to Pushgateway may become stale if not updated regularly, leading to inaccurate monitoring and analysis.
  3. Potential Single Point of Failure: Pushgateway can become a single point of failure if it is not properly managed or if it experiences downtime, impacting the availability of metrics.
  4. Security Considerations: Requires careful consideration of security practices to ensure that access to Pushgateway endpoints is properly secured to prevent unauthorized access or tampering with metrics data.

Despite these challenges, Prometheus Pushgateway remains a valuable tool for collecting metrics from short-lived or dynamic targets, providing essential functionality for monitoring modern, dynamic environments.

Best Practices for using Prometheus Pushgateway

To effectively implement Prometheus Pushgateway, consider the following best practices:

  • Labeling Metrics: Include appropriate labels in your metrics to distinguish different job instances or types.
  • Avoid Overwriting: Ensure metrics pushed to the Pushgateway have unique identifiers to prevent overwriting.
  • Expiration Policies: Set expiration policies for metrics in the Pushgateway to avoid accumulating stale data.
  • Security Considerations: Secure access to the Pushgateway endpoint to prevent unauthorized access.
  • Monitoring Pushgateway: Monitor the Pushgateway instance itself to ensure availability and performance.

Prerequisites

To follow this tutorial, you will need:

Steps to Run Prometheus Pushgateway on Linux

Step#1:Install Prometheus Pushgateway

The most convenient way to install,is to visit the GitHub page for Prometheus Pushgateway releases, and download those binaries there.

Understanding Prometheus Pushgateway with Examples 3
wget https://github.com/prometheus/pushgateway/releases/download/v1.7.0/pushgateway-1.7.0.linux-amd64.tar.gz
Understanding Prometheus Pushgateway with Examples 4

Extract the download prometheus pushgateway binary file

tar xvfz pushgateway-1.7.0.linux-amd64.tar.gz
Understanding Prometheus Pushgateway with Examples 5

Step#2:Start the pushgateway with the command

Start the pushgateway with the command

 ./pushgateway
Understanding Prometheus Pushgateway with Examples 6

Step#3:Access the Pushgateway on the browser

Access the Prometheus Pushgateway on the browser with URL – http://localhost:9091

Understanding Prometheus Pushgateway with Examples 7
Understanding Prometheus Pushgateway with Examples 8
Understanding Prometheus Pushgateway with Examples 9

The default options given by Pushgateway should work well in most cases. Here they are with the explanation of each of them:

  • –web.listen-address=:9091, IP (optional) and port pair on which to listen for requests;
  • –web.telemetry-path=/metrics, Path under which the metrics (both user-sent and internal ones) of the Pushgateway will be exposed;
  • –web.external-url=, URL on which this Pushgateway is externally available. Useful if you expose it via some domain name;
  • –web.route-prefix=, if specified then uses this as a prefix for all of the routes. Defaults to –web.external-url’s prefix;
  • –web.enable-lifecycle, if specified then lets you shut the Pushgateway via the API;
  • –web.enable-admin-api, if specified then enables the Admin API. It lets you perform certain destructive actions. More on that in the following sections;
  • –persistence.file=, if specified then Pushgateway writes its state to this file every –persistence.interval time period;
  • –persistence.interval=5m, how often the state should be written to the previously specified file;
  • –push.disable-consistency-check, if specified then the metrics are not checked for correctness at ingestion time. Should not be specified in the absolute majority of cases;
  • –log.level=info, one of debug, info, warn, error. Only prints messages with levels higher than that;
  • –log.format=logfmt, possible values: logfmt, json. Specify json if you want structured logs that could be used with, for example, Elasticsearch.

Conclusion:

In conclusion, Prometheus Pushgateway provides a vital solution for capturing metrics from short-lived or batch jobs, enabling effective monitoring in dynamic environments. With its straightforward integration, temporary metric storage, and seamless compatibility with Prometheus, Pushgateway enhances system observability, aiding in troubleshooting and performance optimization efforts.

Related Articles:

How to Install Prometheus on Ubuntu 22.04 LTS

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Reference:

Prometheus Documentation Official Page

Akash Bhujbal

Hey, I am Akash Bhujbal, I am an aspiring DevOps and Cloud enthusiast who is eager to embark on a journey into the world of DevOps and Cloud. With a strong passion for technology and a keen interest in DevOps and Cloud based solutions, I am driven to learn and contribute to the ever-evolving field of DevOps and Cloud.

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