Yes, it is possible to add Redis to CageFS and isolate data for each hosting account. CageFS is a component of CloudLinux that provides a virtualized file system environment for users within shared hosting environments. It allows you to isolate user accounts from each other, providing an extra layer of security and resource isolation.

To achieve this with Redis, you'll need to follow these general steps:

1. Install Redis: First, you'll need to install Redis on your server. This can typically be done using your package manager (e.g., apt for Debian-based systems, yum for Red Hat-based systems).

2. Configure Redis for Multiple Instances: Redis supports running multiple instances on the same server, each with its own configuration and data directory. You'll need to set up multiple Redis instances, one for each hosting account you want to isolate.

3. Create Separate Data Directories: For each Redis instance, create a separate data directory where the instance will store its data. Make sure each directory is specific to a hosting account and is not accessible by other users.

4. Configure Redis Instances: Edit the configuration files for each Redis instance to specify the unique data directory, port, and other settings. Make sure each instance is configured to run on a different port to avoid conflicts.

5. Set Up CageFS Mount Points: Configure CageFS to mount the separate data directories for each Redis instance. This will ensure that each hosting account can only access its own Redis data.

6. Add Redis to CageFS: Include the Redis binaries and necessary files in the CageFS template so that they are available to users within the virtualized environment.

7. Enable CageFS for Hosting Accounts: Enable CageFS for the hosting accounts that require access to Redis. This will ensure that they are restricted to their own isolated environment.

8. Start Redis Instances: Start the Redis instances using the configurations you've set up. Each instance should now use its own isolated data directory.

By following these steps, you can effectively add Redis to CageFS and ensure that each hosting account has its own isolated Redis environment. This provides an extra layer of security and resource isolation in a shared hosting environment. Keep in mind that this process may vary slightly depending on your specific server configuration and hosting environment. Always make sure to test any changes in a controlled environment before deploying them on a production server.