I know dracut can update modules in initramfs, but I think it is too slow. So I'm wondering what is the fastest way to update modules in initramfs of CentOS 7?
Thanks!
On Sun, Feb 25, 2018 at 8:29 PM wuzhouhui wuzhouhui14@mails.ucas.ac.cn wrote:
I know dracut can update modules in initramfs, but I think it is too slow. So I'm wondering what is the fastest way to update modules in initramfs of CentOS 7?
`dracut` calls `mkinitrd` which rebuilds the initrd file. . . you could do it manually but that is prone to errors ( https://access.redhat.com/solutions/24029).
-----Original Messages----- From: "Steven Tardy" sjt5atra@gmail.com Sent Time: 2018-02-26 10:48:48 (Monday) To: "CentOS mailing list" centos@centos.org Cc: Subject: Re: [CentOS] How to update modules in iniramfs fastly
On Sun, Feb 25, 2018 at 8:29 PM wuzhouhui wuzhouhui14@mails.ucas.ac.cn wrote:
I know dracut can update modules in initramfs, but I think it is too slow. So I'm wondering what is the fastest way to update modules in initramfs of CentOS 7?
`dracut` calls `mkinitrd` which rebuilds the initrd file. . . you could do it manually but that is prone to errors ( https://access.redhat.com/solutions/24029).
This solution does not work in CentOS 7, because initramfs in CentOS 7 is not a gzipped cpio: [root@bogon a]# file /boot/initramfs-3.10.0-693.el7.x86_64.img /boot/initramfs-3.10.0-693.el7.x86_64.img: ASCII cpio archive (SVR4 with no CRC) If I use zcat /boot/initrd-2.6.18-164.6.1.el5.img | cpio -idmv to uncompress initramfs, it will report errors: [root@bogon a]# zcat /boot/initramfs-3.10.0-693.el7.x86_64.img | cpio -idmv
gzip: /boot/initramfs-3.10.0-693.el7.x86_64.img: not in gzip format cpio: premature end of archive
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On Mon, 26 Feb 2018, wuzhouhui wrote:
-----Original Messages----- From: "Steven Tardy" sjt5atra@gmail.com Sent Time: 2018-02-26 10:48:48 (Monday) To: "CentOS mailing list" centos@centos.org Cc: Subject: Re: [CentOS] How to update modules in iniramfs fastly
On Sun, Feb 25, 2018 at 8:29 PM wuzhouhui wuzhouhui14@mails.ucas.ac.cn wrote:
I know dracut can update modules in initramfs, but I think it is too slow. So I'm wondering what is the fastest way to update modules in initramfs of CentOS 7?
`dracut` calls `mkinitrd` which rebuilds the initrd file. . . you could do it manually but that is prone to errors ( https://access.redhat.com/solutions/24029).
i think you have that backwards ... mkinitrd is simply a wrapper around a call to dracut, which builds an initramfs.
This solution does not work in CentOS 7, because initramfs in CentOS 7 is not a gzipped cpio:
it is, but to get to the content, you need to use "skipcpio" to jump over the initial tiny cpio archive. see, for example:
https://sites.google.com/site/syscookbook/rhel/rhel-kernel-rebuild
rday
So, in the end, we can't recreate initramfs of CentOS 7 manually just like https://access.redhat.com/solutions/24029 did in CentOS 6?
-----Original Messages----- From: "Robert P. J. Day" rpjday@crashcourse.ca Sent Time: 2018-02-26 14:05:24 (Monday) To: "CentOS mailing list" centos@centos.org Cc: Subject: Re: [CentOS] How to update modules in iniramfs fastly
On Mon, 26 Feb 2018, wuzhouhui wrote:
-----Original Messages----- From: "Steven Tardy" sjt5atra@gmail.com Sent Time: 2018-02-26 10:48:48 (Monday) To: "CentOS mailing list" centos@centos.org Cc: Subject: Re: [CentOS] How to update modules in iniramfs fastly
On Sun, Feb 25, 2018 at 8:29 PM wuzhouhui wuzhouhui14@mails.ucas.ac.cn wrote:
I know dracut can update modules in initramfs, but I think it is too slow. So I'm wondering what is the fastest way to update modules in initramfs of CentOS 7?
`dracut` calls `mkinitrd` which rebuilds the initrd file. . . you could do it manually but that is prone to errors ( https://access.redhat.com/solutions/24029).
i think you have that backwards ... mkinitrd is simply a wrapper around a call to dracut, which builds an initramfs.
This solution does not work in CentOS 7, because initramfs in CentOS 7 is not a gzipped cpio:
it is, but to get to the content, you need to use "skipcpio" to jump over the initial tiny cpio archive. see, for example:
https://sites.google.com/site/syscookbook/rhel/rhel-kernel-rebuild
rday _______________________________________________ CentOS mailing list CentOS@centos.org https://lists.centos.org/mailman/listinfo/centos
Am 26.02.2018 um 06:46 schrieb wuzhouhui wuzhouhui14@mails.ucas.ac.cn:
-----Original Messages----- From: "Steven Tardy" sjt5atra@gmail.com Sent Time: 2018-02-26 10:48:48 (Monday) To: "CentOS mailing list" centos@centos.org Cc: Subject: Re: [CentOS] How to update modules in iniramfs fastly
On Sun, Feb 25, 2018 at 8:29 PM wuzhouhui wuzhouhui14@mails.ucas.ac.cn wrote:
I know dracut can update modules in initramfs, but I think it is too slow. So I'm wondering what is the fastest way to update modules in initramfs of CentOS 7?
`dracut` calls `mkinitrd` which rebuilds the initrd file. . . you could do it manually but that is prone to errors ( https://access.redhat.com/solutions/24029).
This solution does not work in CentOS 7, because initramfs in CentOS 7 is not a gzipped cpio: [root@bogon a]# file /boot/initramfs-3.10.0-693.el7.x86_64.img /boot/initramfs-3.10.0-693.el7.x86_64.img: ASCII cpio archive (SVR4 with no CRC) If I use zcat /boot/initrd-2.6.18-164.6.1.el5.img | cpio -idmv to uncompress initramfs, it will report errors: [root@bogon a]# zcat /boot/initramfs-3.10.0-693.el7.x86_64.img | cpio -idmv
gzip: /boot/initramfs-3.10.0-693.el7.x86_64.img: not in gzip format cpio: premature end of archive
Maybe some ucode archive is in front of the initrd archive.
Did you try to unpack it without uncompressing it? Whats the contents?
-- LF
-----Original Messages----- From: "Leon Fauster" leonfauster@googlemail.com Sent Time: 2018-02-26 22:20:51 (Monday) To: "CentOS mailing list" centos@centos.org Cc: Subject: Re: [CentOS] How to update modules in iniramfs fastly
Am 26.02.2018 um 06:46 schrieb wuzhouhui wuzhouhui14@mails.ucas.ac.cn:
-----Original Messages----- From: "Steven Tardy" sjt5atra@gmail.com Sent Time: 2018-02-26 10:48:48 (Monday) To: "CentOS mailing list" centos@centos.org Cc: Subject: Re: [CentOS] How to update modules in iniramfs fastly
On Sun, Feb 25, 2018 at 8:29 PM wuzhouhui wuzhouhui14@mails.ucas.ac.cn wrote:
I know dracut can update modules in initramfs, but I think it is too slow. So I'm wondering what is the fastest way to update modules in initramfs of CentOS 7?
`dracut` calls `mkinitrd` which rebuilds the initrd file. . . you could do it manually but that is prone to errors ( https://access.redhat.com/solutions/24029).
This solution does not work in CentOS 7, because initramfs in CentOS 7 is not a gzipped cpio: [root@bogon a]# file /boot/initramfs-3.10.0-693.el7.x86_64.img /boot/initramfs-3.10.0-693.el7.x86_64.img: ASCII cpio archive (SVR4 with no CRC) If I use zcat /boot/initrd-2.6.18-164.6.1.el5.img | cpio -idmv to uncompress initramfs, it will report errors: [root@bogon a]# zcat /boot/initramfs-3.10.0-693.el7.x86_64.img | cpio -idmv
gzip: /boot/initramfs-3.10.0-693.el7.x86_64.img: not in gzip format cpio: premature end of archive
Maybe some ucode archive is in front of the initrd archive.
Did you try to unpack it without uncompressing it? Whats the contents?
[root@bogon a]# cpio -id < /boot/initramfs-3.10.0-693.el7.x86_64.img 28 blocks [root@bogon a]# ls -R .: early_cpio kernel
./kernel: x86
./kernel/x86: microcode
./kernel/x86/microcode: GenuineIntel.bin
Obviously, above is not what I want. In order to get full contents of initramfs, I have to use skipcpio to skip initial cpio of initramfs:
[root@bogon a]# /usr/lib/dracut/skipcpio /boot/initramfs-3.10.0-693.el7.x86_64.img | zcat | cpio -id 85469 blocks [root@bogon a]# ls bin etc lib proc run shutdown sysroot usr dev init lib64 root sbin sys tmp var
I can use skipcpio to get full contents of initramfs, and then edit files in it. But the problem is how to recreate initramfs by extracted contents?
-- LF
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wuzhouhui