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Re: [alpine-user] Lack of a minimal documentation on Alpine's overall architecture, run-from-RAM feature, mkinitfs, modloop etc.

From: Cág <>
Date: Mon, 9 Apr 2018 13:53:39 +0000


Sorry for the late reply.

Timur Fayzrakhmanov wrote:
> There are other things in question:
> - Alpine overall architecture;

What do you mean by that? The base of Alpine is BusyBox/musl/apk.

> - What is modloop!?

Modloop is a kernel module for loop devices.

> - Booting process description;
> - How kernel, initramfs (its init script) and init (OpenRC) are
> related to each other;

OpenRC is not init on Alpine, it's a service manager. /sbin/init is
a link to /bin/busybox. The openrc package also provides init scripts.
/etc/inittab describes the boot process, which is:

/sbin/init -> /sbin/openrc sysinit -> /sbin/openrc boot ->
        /sbin/openrc default -> ttys are spawned

initramfs is caught by the kernel and the bootloader, only after it is
started /sbin/init is being executed. Read more about the Linux booting
process and initramfs on Wikipedia or elsewhere, I myself never use it.

> (you can doubt it but Alpine tends to adopt things in its own way and
> I think it should be covered somehow)

It doesn't really.

Received on Mon Apr 09 2018 - 13:53:39 UTC