CentOS Linux Server Installation , FAQ, Tips and Tricks

CentOS Linux, Red Hat Linux and Virtualization

Solving Kernel Panic issues, No Operating system found after VMWare Consolidation for old Redhat Server

We are migrating an old Redhat 7.2 system into out VMware VSphere 4.x recently (using hot clone). The process of consolidating is a bit tricky. Please take note that we cannot import the RedHat7.2 into the VMware Esx4.1 directly, the migration stuck at 1% forever. Thus, we downgraded our ESX 4.1 to 4.0 and perform the migration from VMware Stand Alone convertor one version earlier.

Please find the process as below:-

Machine

OS: Redhat 7.2

Hard disk information

Disk /dev/hda: 255 heads, 63 sectors, 4865 cylinders
Units = cylinders of 16065 * 512 bytes

Device Boot Start End Blocks Id System
/dev/hda1 * 1 6 48163+ 83 Linux
/dev/hda2 7 133 1020127+ 82 Linux swap
/dev/hda3 134 4865 38009790 83 Linux

Step1: Consolidate the physical machine to virtual machine using SCSI Bus Logic disk controller driver

There is some problem that I faced when I used default SCSI LSI Logic disk controller driver. The drive is would be recognized and no drive could be booted or found. Also be sure to put VMWare Helper IP under Helper VMware configuration.

Step 2: Change SCSI Disk Controller Type

After P2V virtualization. Login to your VSphere. Change the Disk Controller from BusLogic Parallel to LSI Logic Parallel. Else you will faced the Operating Not found issue or you cannot find any Linux partition using fdisk -l command under system rescue.

Step 3: Boot from Linux rescue CD

Boot from any Linux rescue CD. I am using CentOS Linux to perform the rescue function. Once the CD boot type in "linux rescue". Follow all the process. Skip the network setup process.

Step4: Mount the virtual machine file system

chroot /mnt/sysimage

Step5: Edit the /etc/modules.conf

Add in the following line so that our BusLogic can be booted

vi /etc/modules.conf

alias scsi_hostadapter BusLogic

Step6: Edit the /etc/fstab

Change the fstab table so that the swap partition table can be mounted

vi /etc/fstab

/dev/sda2 swap swap defaults 0 0

Step7: Reinitialize the kernel images and modules

Creates an initial image used by the kernel for preloading the block device modules

mkinitrd -v -f /boot/initrd-2.x.y-zz.img 2.x.y-zz

Step8: Edit the /etc/grub.conf

Basically,we need to change the boot, splashimage root line. This is to ensure the grub can be booted correctly

vi /etc/grub.conf

# grub.conf generated by anaconda
#
# Note that you do not have to rerun grub after making changes to this file
# NOTICE: You have a /boot partition. This means that
# all kernel and initrd paths are relative to /boot/, eg.
# root (hd0,0)
# kernel /vmlinuz-version ro root=/dev/hda3
# initrd /initrd-version.img
#boot=/dev/sda
default=0
timeout=10
splashimage=(sd0,0)/grub/splash.xpm.gz
title Red Hat Linux (2.4.7-10)
root (hd0,0)
kernel /vmlinuz-2.4.7-10 ro root=/dev/sda3
initrd /initrd-2.4.7-10.img

Step9: Reinstall Grub

grub-install --recheck /dev/sda
grub-install /dev/sda

Step 10: Shutdown the Vmware machine

We had completed all the necessary task, next we need to shutdown the machine for SCSI bus configuration

init 0

Step 11: Change the controller type

We need to change the controller type back to Bus Logic again

Step 11: Run kudzu to reinitialize the new hardware install
After you boot yp your Linux machine, let us update the hardwae changes.

kudzu

Step 12: Install vmware tools

Note: I unable to mount my cdrom at this moment..still finding a solution to workout.

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