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Lord of the OS 29 May 2013

Posted by Maulvi Bakar in : Linux,Society,System,Unix , add a comment

Recently I visited a friend who is an average computer user. As we were talking he mentioned that he had recently installed Windows 8 on his PC. He told me how happy he was with this operating system and showed me the Windows 8 DVD. To his surprise I threw it into his microwave oven and turned it on. Instantly he got very upset, because the DVD had become precious to him, but I told him: ‘Do not worry, it is unharmed.’ After a few minutes I took the CD out, gave it to him and said: ‘Take a close look at it.’ To his surprise the DVD was quite cool to hold and he remarked that it seemed to be heavier than before. At first he could not see anything, but on the inner edge of the central hole he saw an inscription, an inscription finer than anything he had ever seen before. The inscription shone piercingly bright, and yet remote, as if out of a great depth:

12413AEB2ED4FA5E6F7D78E78BEDE820945092OF923A40EElOE5 I OCC98D444AA08EI

‘I cannot understand these fiery letters,’ he said in a timid voice.
‘No but I can,’ I said. ‘The letters are HEX, of an ancient mode, but the language is that of Microsoft, which I shall not utter here. But in common English this is what it says:

One OS to rule them all, One OS to find them,
One OS to bring them all and in the darkness bind them

It is only two lines from a verse long known in System-lore:

Three OS’s from corporate-kings in their towers of glass,
Seven from valley-lords where orchards used to grow,
Nine from dotcoms doomed to die,
One from the Dark Lord Gates on his dark throne
In the Land of Redmond where the Shadows lie.
One OS to rule them all, One OS to find them,
One OS to bring them all and in the darkness bind them,
In the Land of Redmond where the Shadows lie.

dracut Warning: No root device “block:/dev/disk/by-label/root” found – CentOS 6 19 May 2013

Posted by Maulvi Bakar in : Linux,System,Work , add a comment

I’ve been on GE-mode for the past few months. In effort to maintain stability, I resisted upgrading the KVM-host machine to the latest kernel. Sorry guys, I’m still on CentOS, not on OEL, so no Ksplice!

To cut story short, the kernel upgrades results in the infamous CentOS/RHEL depmod bug! –

dracut Warning: No root device "block:/dev/disk/by-label/root" found
dracut Warning: Boot has failed. To debug this issue add "rdshell" to the kernel command line.
dracut Warning: Signal caught!
dracut Warning: Boot has failed. To debug this issue add "rdshell" to the kernel command line.
Kernel panic - not syncing: Attempted to kill init!
Pid: 1, comm: init Not tainted 2.6.32-358.6.2.el6.x86_64 #1
Call Trace:
[] ? panic+0x78/0x143
[] ? do_exit+0x852/0x860
[] ? fput+0x25/0x30
[] ? do_group_exit+0x58/0xd0
[] ? sys_exit_group+0x17/0x20
[] ? system_call_fastpath+0x16/0x1b

The system kernel-panics!

Even the built-in kernel fallback options in GRUB did not activate!!

Canvassing the net suggests that the kernel modules did not install properly and the solution is to install manually via the commands below –

# depmod -ae -F /boot/System.map-2.6.32-358.6.2.el6.x86_64 2.6.32-358.6.2.el6.x86_64
# dracut --force '' 2.6.32-358.6.2.el6.x86_64

I tried that via CentOS Rescue Mode and ‘chroot /mnt/sysimage’. This too was fun, KVM Console ISO Image redirection from your local PC to a site on the far side of the galaxy is something you should only attempt on a high-bandwidth! UniFi is crap!

Luckily the KVM Console supports mounting ISO Image from a SAMBA Share. A small tiny low-end-box serves the purpose nicely and being much closer in peering to the main KVM-host site makes it even better!

Unfortunately, that doesn’t seem to work for me.

But what does work – instead of ‘yum update’, I did a ‘yum localinstall’. Downloaded the kernel and kernel-devel RPMs onto the local disk and installed it after removing the broken kernel before that.

That seems to do the trick!

Hope it solves someone else issue with this.

God willing!

π