# Fluentd GEM_PATH Not Updating: Fix & Workarounds
**Having trouble getting Fluentd to recognize gems installed in a custom directory?** You're not alone! Many users encounter this when they try to manage their Fluentd plugins and dependencies outside the default installation path. This article dives deep into why this happens and, more importantly, how you can overcome it without resorting to modifying core scripts. We'll explore the intricacies of the `GEM_PATH` environment variable and how Fluentd interacts with it, offering practical solutions to ensure your custom gems are loaded correctly.
## Understanding the GEM_PATH Environment Variable
The **`GEM_PATH` environment variable** is a cornerstone of Ruby's gem management system. It tells the Ruby interpreter and associated tools, like `gem` and `fluent-gem`, where to look for installed gems. When you install gems, they are typically placed in a default location determined by your Ruby installation or package manager. However, for various reasons – such as avoiding conflicts, managing different versions, or deploying to restricted environments – you might want to install gems in a custom directory. This is where `GEM_PATH` comes into play. By setting `GEM_PATH` to include your custom gem directory, you're instructing Ruby to also search for gems in that specific location. It's crucial to understand that `GEM_PATH` can be a colon-separated list of directories, allowing you to specify multiple locations. The order matters; Ruby will search these directories from left to right. If you're trying to install gems for a specific application, like Fluentd, and want to isolate those dependencies, setting `GEM_PATH` is the standard approach. For instance, if you install a plugin like `fluent-plugin-datadog` to `/opt/additionalgems`, you'd expect to add this path to your `GEM_PATH`. The challenge arises when the application itself, or its startup mechanism, doesn't correctly respect the environment variable as set externally. This is precisely the scenario many users face with Fluentd, as we'll explore next.
## The Fluentd GEM_PATH Challenge: What's Going Wrong?
This is where the core of the problem lies for many users. You've meticulously installed your gems, say `fluent-plugin-datadog`, to a custom directory like `/opt/additionalgems` using `fluent-gem install --install-dir /opt/additionalgems fluent-plugin-datadog`. You've then dutifully updated your `GEM_PATH` environment variable, perhaps setting it to `/opt/additionalgems:/path/to/default/gems`. Logically, you'd expect Fluentd to find and load the `datadog` plugin when you run it. However, Fluentd continues to report that the `datadog` plugin is not found, stubbornly sticking to gems in its default path. The root cause, as identified in the user's report, often lies within the **wrapper script** used to launch Fluentd, typically found at `/usr/sbin/fluentd`. This script, in its effort to ensure a consistent environment, **hard-codes** the `GEM_HOME` and `GEM_PATH` environment variables to specific, default locations (e.g., `/opt/fluent/lib/ruby/gems/3.4.0/`). This hard-coded value effectively **overrides** any `GEM_PATH` you set externally before running the script. Consequently, even though your `fluent-gem` command might correctly list the custom-installed gem (because `fluent-gem` itself might not be subject to the same hard-coded wrapper script), the Fluentd process launched by the wrapper script doesn't
