Gentoo Archives: gentoo-dev

From: "Robin H. Johnson" <robbat2@g.o>
To: gentoo-dev@l.g.o
Subject: Re: [gentoo-dev] udev and /usr
Date: Thu, 15 Sep 2011 20:33:49
Message-Id: robbat2-20110915T201249-548068356Z@orbis-terrarum.net
In Reply to: Re: [gentoo-dev] udev and /usr by Joost Roeleveld
1 On Thu, Sep 15, 2011 at 10:03:53PM +0200, Joost Roeleveld wrote:
2 > On Thursday, September 15, 2011 09:27:06 AM Zac Medico wrote:
3 > > On 09/15/2011 09:04 AM, Joost Roeleveld wrote:
4 > > > Thank you for your response, however, I do have a few questions about
5 > > > this. Where will this default initramfs actually need to be placed?
6 > >
7 > > It should be similar to how sys-apps/v86d is used for uvesafb support.
8 > > It installs /usr/share/v86d/initramfs and when you configure your
9 > > kernel, you set CONFIG_INITRAMFS_SOURCE="/usr/share/v86d/initramfs" in
10 > > order to have in included in your kernel image.
11 > Will this be set somewhere globally to the initramfs automatically?
12 > And doesn't this mean that a new kernel will need to be build just to satisfy
13 > this?
14 >
15 > I'm trying to think of how best to avoid users who are not aware to get caught
16 > with non-booting systems.
17 >
18 > Wouldn't automatic inclusion into grub.conf be a better approach? Not sure if
19 > grub.conf can handle a "global" setting for initramfs.
20 Grub doesn't support a global initramfs setting, but you can build a
21 static initramfs for v86d if needed.
22
23 > > > Also, how will
24 > > > we be able to deal with situations where this script fails?
25 > > It should drop you to a minimal shell.
26 > But, with udev then failing, will there be the /dev-entries to mount the
27 > different partitions to fix the environment?
28 Yes, /dev is provided by devtmpfs already, and that is populated by the
29 kernel.
30
31 > > > If Gentoo does decide to follow the initramfs-route, why not simply
32 > > > implement /etc/init.d/localmount in the initramfs?
33 > > I think that's pretty close to what we have planned, since the plan is
34 > > to have the initramfs mount configuration stored on the root filesystem.
35 > But still require a seperate configuration file for this?
36 The configuration file isn't actually required, but it's there in case
37 you want to specify MORE filesystems to mount before switching to the
38 rootfs init.
39
40 There are two files to load from the rootfs:
41 1. /etc/fstab
42 2. /etc/minimal-filesystems.cfg [exact name undecided]
43
44 The list is in the second file, just one mountpoint per line.
45 Defaults to /usr, /var
46 If the file is not available, the default is also /usr, /var.
47
48 For each filesystem for the minimal list, use the line from fstab to
49 mount it. This covers getting the device, mountpoint and mount options.
50
51 There is a catch to this:
52 If those non-root filesystems live on LVM or something complex, you're
53 going to need to use a more advanced initramfs,
54 genkernel/dracut/roll-your-own.
55
56 > On my desktop, that would mean the following list:
57 > /usr/
58 > /var/
59 Only these two should be needed to early-boot the system successfully.
60
61
62 > True, but I don't have any scripts configured for udev on my desktop.
63 > My server has some scripts related to Xen, and those are all under
64 > /etc/xen/...
65 >
66 > In this case, would it still be necessary to use an initramfs?
67 Where is /usr, and do you have any udev rules that need /var?
68
69 --
70 Robin Hugh Johnson
71 Gentoo Linux: Developer, Trustee & Infrastructure Lead
72 E-Mail : robbat2@g.o
73 GnuPG FP : 11AC BA4F 4778 E3F6 E4ED F38E B27B 944E 3488 4E85

Replies

Subject Author
Re: [gentoo-dev] udev and /usr Joost Roeleveld <joost@××××××××.org>