Contents
What is initramfs tools?
The initramfs is an cpio archive. At boot time, the kernel unpacks that archive into ram, mounts and uses it as initial root file system. From there on the mounting of the real root file system occurs in user space. klibc handles the boot-time networking setup.
How do I read an initramfs file?
How to inspect initramfs
- extract the microcode by cd path/to/initrd/; cpio -i
- extract the basic initrd by cd path/to/initrad/; dd if=/initrd. img of=initrd. img bs=512 skip=48; zcat initrd. img |cpio -i (adjust skip values matching the cpio STDERR output).
What is the use of initramfs?
Detailed Description. Initramfs is used as the first root filesystem that your machine has access to. It is used for mounting the real rootfs which has all your data. The initramfs carries the modules needed for mounting your rootfs.
How to check the content of an initramfs file?
The lsinitramfs command lists the content of given initramfs images. It allows one to quickly check the content of one (or multiple) specified initramfs files. -h Display usage information and exit. -l Display long and more verbose listing of initramfs content.
Why do I need initramfs for rootfs?
Init is designed to perform certain tasks before the real or final file system is installed on top of rootfs. Thus, initramfs should contain all the device drivers and tools needed to install the final root file system. Download busybox (you can download a newer version):
How to extract initramfs image files in RHEL 7?
This post provides steps to extract initramfs image files for RHEL 7. Unlike previous version, on RHEL 7 using cpio command for the initramfs image file will not extract all files (or will give some error). For example:
How to create a directory hierarchy for initramfs?
In the Busybox Settings menu, select Build Options, and check the box next to Build BusyBox as a static binary (no shared libs). Next, specify the output folder for binaries and collect busybox: 3. Create a directory hierarchy for initramfs: