Cloudwatch Exporter vs Prometheus Node Exporter - jvcastaneda/DevopsToolingConfig GitHub Wiki

The CloudWatch Exporter and Prometheus Node Exporter serve different purposes when monitoring an EC2 instance within a Prometheus-based ecosystem. Here's a detailed comparison:

1. Purpose

CloudWatch Exporter

  • Purpose: Collects and exposes AWS CloudWatch metrics to Prometheus.
  • Allows you to pull metrics from CloudWatch, such as EC2 instance-level metrics (CPU utilization, memory usage, network stats) or other AWS service metrics.
  • It acts as a bridge between CloudWatch and Prometheus.

Prometheus Node Exporter

  • Purpose: Exposes host-level metrics of the EC2 instance itself (or any server it's running on) in a format that Prometheus can scrape.
  • Metrics include CPU, memory, disk usage, file descriptors, network I/O, and other OS-level metrics.

2. Data Source

CloudWatch Exporter

  • Data source: AWS CloudWatch
  • Metrics are pulled directly from CloudWatch APIs, not from the instance itself.
  • It includes pre-aggregated AWS metrics and does not require any software agent running on the EC2 instance.

Prometheus Node Exporter

  • Data source: Local instance OS
  • Collects metrics directly from the EC2 instance’s operating system using tools like /proc filesystem.
  • You need to install and run the node_exporter agent on the EC2 instance.

3. Deployment

CloudWatch Exporter

  • Runs as a standalone service (typically on a separate monitoring server or in the same Prometheus server) and scrapes data via AWS APIs.
  • Requires access to AWS credentials (IAM role or keys) with permissions to read CloudWatch metrics.

Prometheus Node Exporter

  • Runs locally on the EC2 instance as an agent (binary or container).
  • Prometheus scrapes metrics over HTTP from the node_exporter process.

4. Type of Metrics Collected

Metrics CloudWatch Exporter Prometheus Node Exporter
CPU Utilization Available from CloudWatch (aggregated) Precise, per-core CPU stats
Memory Usage Not directly available in CloudWatch Available (used, free, buffers, cache)
Disk Usage CloudWatch reports metrics (e.g., IOPS) Detailed usage per filesystem
Network I/O Available as high-level metrics Detailed per-interface statistics
System Load Not provided Provided (load average, uptime)
File Descriptors Not provided Provided

5. Pros and Cons

CloudWatch Exporter

Pros:

  • No agent installation on the EC2 instance.
  • Pulls pre-aggregated metrics from AWS services.
  • Useful for monitoring AWS-managed services and aggregated EC2 metrics.

Cons:

  • AWS CloudWatch metrics can have a 5-minute delay (basic monitoring).
  • Costs money to query CloudWatch metrics frequently.
  • Limited granularity compared to Node Exporter.

Prometheus Node Exporter

Pros:

  • Provides real-time, detailed system-level metrics.
  • Lightweight and simple to install.
  • Free to use with no AWS API cost.

Cons:

  • Requires installing and maintaining the agent on each EC2 instance.
  • Does not natively integrate with CloudWatch or AWS-specific services.

When to Use Which

  • Use CloudWatch Exporter if:

    • You need aggregated AWS metrics for EC2 instances and other AWS services.
    • You do not want to install additional agents on your instances.
    • You're looking for an overview of CloudWatch metrics in Prometheus.

  • Use Prometheus Node Exporter if:

    • You need detailed system-level metrics (e.g., memory, disk usage, CPU load) from EC2 instances.
    • You can install the Node Exporter agent.
    • You want precise, real-time monitoring.

Summary

  • CloudWatch Exporter: AWS-native, high-level metrics pulled from CloudWatch.
  • Prometheus Node Exporter: Instance-local, detailed OS-level metrics.

Both can complement each other for comprehensive monitoring in a Prometheus setup! 🚀

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