The Global Zone is non-persistent. It is booted from a ramdisk on each system boot. This ramdisk may be loaded from local bootable media (USB key, CDROM, etc) or from the network (PXE, etc.).
There are some exceptions to the non-persistence. You can configure certain persistent settings in /usbkey. They are applied on reboot.
There are a few configuration files and folders in /usbkey.
- /usbkey/config - system configuration options
- /usbkey/config.inc/ - a directory where certain files referenced by /usbkey/config will reside (not present by default)
- /usbkey/shadow - the shadow password file that will be put in /etc/shadow (read-only) on system boot
- /usbkey/ssh/ - a directory containing the SSH client and server configuration (deployed to /etc/ssh/ on system boot)
- /usbkey/ssh/sshd_config is in here so if you want to do things like require MFA or refuse Password login, you change it here and reboot