GoKawiilPersistence by Choice
The immutable nature of Lightwhale offers clear advantages, but in order to install, configure, run containers, and write data, a writable filesystem is required. And for the system to be genuinely useful, such changes must persist across reboots.
The Data Filesystem
Lightwhale provides both temporary and persistent writability through an automated subsystem activated early during startup. This mounts the data filesystem at /mnt/lightwhale-data .
All data written by Lightwhale is kept within a single subdirectory: /mnt/lightwhale-data/lightwhale-state . This in turn serves as the writable upper layer in an overlayfs stack, with the immutable root as the lower layer.
By default, Lightwhale mounts a volatile tmpfs as its data filesystem. When persistence is enabled, the data filesystem instead resides on a storage device and is mounted accordingly.
Key Directories
The data filesystem overlay does not cover the entire root filesystem; that would defeat the purpose of immutability and Lightwhale altogether. Instead, the writable overlays apply only to a few strategic directories:
/etc For customizing system configuration, including networking, password, and sshd settings. /var For log and other application data. /home For user account customization, including authorized SSH keys, and cloning Git repositories with Docker and Swarm stacks.
Docker Data
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