Early user space or initial memory images, known as initramfs
images, are typically used as early user spaces with the task of mounting complex filesystems, such as for example when an encrypted partition needs to be set up. For that use case, initramfs
will prepare the final root filesystem and then perform a switch_root
, effectively replacing the old filesystem with the new and running a new init
from the new filesystem. initramfs
needs to contain all tools needed to mount the final root filesystem.
Other uses for initramfs
include rescue and manufacturing systems.
This recipe will show how to configure the Yocto build system to build initramfs
images.
When the Linux kernel mounts a file system from physical storage, it keeps a cache for quick access. A memory filesystem is just this kernel cache without a backing store.
An initramfs
is a compressed cpio
format file that the kernel extracts into a memory filesystem and uses as the root filesystem...