Glowroot: A lightweight and powerful open-source APM tool

Glowroot is an open-source Application Performance Monitoring (APM) tool designed to monitor and analyze the performance of Java applications. Known for its simplicity, lightweight nature, and non-intrusive design, Glowroot provides essential features for optimizing applications in production and detecting bottlenecks.

Introduction to Glowroot

Glowroot operates as a Java agent, integrating directly into applications to collect performance metrics. Unlike other heavier and more expensive solutions, Glowroot stands out for its ease of configuration and minimal resource footprint. It offers deep visibility into query execution, response times, and performance issues.

Distributed under the Apache 2.0 license, Glowroot is free to use and customizable to meet developers' needs.

Why use Glowroot?

Glowroot is particularly useful in various scenarios:

Performance optimization: It helps identify slow methods, long-running transactions, and resource contention issues.
Production monitoring: With its low overhead, Glowroot can monitor production environments without significant impact on performance.
Proactive analysis: Configurable alerts enable early action before end users are affected.
Free and open-source: Unlike paid solutions such as New Relic or AppDynamics, Glowroot is accessible to everyone at no additional cost.

You can explore the source code and contribute to the project here: Glowroot GitHub Repository.

Key features

Glowroot offers a range of features that address most APM needs:

Transaction monitoring: Detailed visualization of HTTP requests, JDBC queries, JMS, and Java methods.
Error tracking: Detection and logging of exceptions and application errors.
Configurable alerts: Notifications based on thresholds for response times, CPU usage, and more.
Interactive dashboards: Graphical presentation of metrics with aggregated and detailed views.
Slow query tracking: Trace analysis to pinpoint the slowest queries or problematic methods.
Compatibility: Works with Java 6 and later versions and supports application servers like Tomcat, Jetty, and WildFly.

Tutorial: Installing and configuring Glowroot

Step 1: Downloading Glowroot

Visit Glowroot's official website (glowroot.org) and download the archive for the desired version.

Extract the archive to a directory of your choice.

Step 2: Configuring the Agent

Add the following option when starting your Java application:

java -javaagent:/path/to/glowroot.jar -jar your-application.jar

Replace /path/to/glowroot.jar with the actual path to the file.

On the first run, Glowroot will create a glowroot/ configuration folder with the necessary files.

Step 3: Accessing the Glowroot interface

By default, Glowroot launches a web interface on port 4000. Access it via the following URL:

http://localhost:4000

Step 4: Advanced configuration (Optional)

Customize settings in the glowroot/config.json file to define alert thresholds, enable remote access, or modify collection parameters.

Glowroot is an ideal APM solution for developers seeking to monitor Java applications efficiently without overburdening their infrastructure. Easy to install and configure, it provides valuable insights to optimize performance and enhance user experience. With Glowroot, you have a robust, free, and adaptable tool at your disposal.