Plugin Installation Fails Due to File Permissions

[DoloMike]

Description

In WSL2, the Minecraft server container fails to download and save plugins (e.g., WorldEdit) to the /data/plugins/ directory. The following error appears in the container logs:

java.nio.file.AccessDeniedException: /data/plugins/worldedit-bukkit-7.3.0.jar

This issue occurs when the local plugins directory has restrictive permissions, preventing the container from writing files.

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Root Cause

1. Permissions Issue:

   • The local ./plugins directory was owned by root with restrictive permissions (drwxr-xr-x).
   • The container process, running as a non-root user, could not write to the directory.

2. File System Binding:

   • The ./plugins directory is mounted to /data/plugins in the container using docker-compose.yml.
   • The container requires write permissions on the mounted directory to save downloaded plugins.

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Steps to Reproduce

1. Create a plugins directory locally:
2. Mount the directory in docker-compose.yml:

   volumes:
     - ./plugins:/data/plugins

3. Start the Minecraft server container: docker-compose up
4. Observe the container logs showing a java.nio.file.AccessDeniedException when attempting to download plugins:
   docker logs -f <container-id>

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Solution

Update Directory Permissions

1. Change ownership of the local plugins directory:
   sudo chown -R $(whoami):$(whoami) plugins
2. Ensure the directory is writable:
   chmod -R 777 plugins

Restart the Server

1. Stop the Minecraft server container: docker-compose down
2. Restart the server: docker-compose up

Verify Plugin Installation

1. Check the container logs to confirm the plugin downloads successfully: docker logs -f <container-id>
2. Verify the plugin exists in the plugins directory: ls ./plugins

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Key Findings

• The plugins directory must have appropriate write permissions (e.g., 777) to allow the container to write files.
• Containers running as non-root users will fail to write to directories with restrictive permissions (e.g., drwxr-xr-x owned by root).

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Recommended Fix

Update Documentation

1. Ensure local directories used as Docker volumes (e.g., ./plugins/) are writable.
2. Provide an example command to set appropriate permissions:
   chmod -R 777 plugins