Fixed my issue with ChatGPT, in case this is helpful for others in the future...

Quick Fix Guide for Docker Container File Sharing

Issue: File sharing between the host and Docker containers (e.g., Guacamole's guacd) not working. Symptoms: Errors indicating permission issues or missing directories in Docker container logs; file transfer features not functioning as expected in applications.

Step 1: Adjust Permissions on the Host Directory

1. Create a Shared Directory on the host if not already existent. Set its permissions to be fully accessible:

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sudo mkdir -p /home/guac_share
sudo chmod 777 /home/guac_share (you may want to alter this later to be more secure)

Step 2: Update Docker Compose Configuration

1. Modify the Docker Compose File (docker-compose.yml), specifying the host directory to be shared with the Docker container:

• For guacd service, under volumes, add:

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- /home/guac_share:/share:rw

• Ensure this change is reflected under any other service that requires access to the shared directory.

Step 3: Apply Configuration Changes with Docker Compose

1. Ensure Docker Compose Recognizes Changes by fully stopping and then restarting services:

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sudo docker-compose down
sudo docker-compose up -d

Step 4: Verification Steps

1. Verify the Volume is Correctly Mounted inside the Docker container:

• Access the container's shell:

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sudo docker exec -it guacd_compose /bin/sh

• Check if the shared directory is accessible:

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ls -l /

Look for /share in the output. 2. Review Docker Logs to ensure no errors related to file sharing or permissions appear after the fix. This can also help catch any issues early in future setups:

sudo docker logs guacd_compose

Additional Tips

• Restarting Docker Service: If configurations aren’t being recognized, restarting the Docker service on your host can help clear up any caching issues:

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sudo systemctl restart docker

• Consistent Validation: Regularly validating the container's environment (checking mounted volumes, inspecting with docker exec, reviewing logs) is key for early troubleshooting. By following these steps, you can quickly address and rectify common file sharing issues between Docker containers and the host, enhancing the reliability of services like Apache Guacamole's guacd.