How to fix “Unable to mount root fs ” Error

Mount point has been created and given to me by the NetAPP engineer. I mounted the space on host. After a performed the mount for some reason it started showing up some wired error message like when I ran “vmware-cmd –l ” I get a message vmware auth failed to login. I thought something really goofed up when I created the “VMKernal” to access NFS mount. I decided to reboot the host and see if that clear the error messages but no it has created more problems for me. When I rebooted the host it gave me message

Something really bad happened ☹ . I started hunting on google to got some clue

http://www.linuxforums.org/forum/linux-kernel/7283-kernal-panic-vfs-unable-mount-root-fs-00-00-a.html

I decided to change boot parameters. In order to do so let the machine boots up and then when you get this screen

Here you press “E or e ” on Key board and it will take you the screen

Again press “E or e” and then it will give you option where you can edit the field and type the value as suggested in the earlier link.

it says above that i gotta change "LABEL=/" to "/dev/hda0"

Once you are done with editing then reboot the host. But in my case situation still persist. So I decided to do more google and here is the command which work like a butter.

“esxcfg-boot ”

Follow the steps.

1. Boot the system and wait till you see following screen .Select here “Service Console only”

2. It will let you inter through into service console (Everything is done through physical connection like ILO).

3. Once you logged in then run the command in following order

1. esxcfg-boot –p

2. esxcfg-boot -b

3. esxcfg-boot –r

Reboot the host and select “VMware ESX server ” and host should bring of the esx.

Enable ssh on ESX host

By default SSH is disabled on ESX hosts and we have to enable SSH. Setting to be done.
Open sshd_config file:

# vi /etc/ssh/sshd_config
Find out line that read as follows:
PermitRootLogin no
Set it as follows:
PermitRootLogin yes

Save and close the file. Restart the sshd:
# /etc/init.d/sshd restart

Serendipity - A Fortunate Accident

16Sep2005
Uploaded by fun_come

No interfaces are available for installing a new cluster

User was trying to setup Microsoft NLB. They added one node and it was successful and when they were trying to add another node it was throwing error

“No interfaces are available for installing a new cluster”

User pointed out that may the VLAN trunking which was implemented couple of weeks back. I was not sure what VLAN has to do with it but when I looked at the error I made a guess that it has something to do with OS rather than VMware. I went to MS support site and gave a search with the error message and found wonderful KB 828258.

………….SNIP …………………………………..SNIP…………………………………

This problem may occur if the subsequent nodes are on servers that were created by using an image. The problem occurs because the servers that are created by using an image may have the same Network GUIDs in their registry if the network adapter is installed as part of the image. The Network Load Balancing Manager uses this GUID to attach and configure Network Load Balancing on the servers. The Network Load Balancing Manager detects the GUID of the first server, and then does not register subsequent network adapters that have the same GUID.

-------------------SNIP………………………………………SNIP………………………………..

It was true because these VM’s was build with “GHOST image”

To resolve this follow these steps in the same sequence

1. Uninstall the tools from the VM’s using add and remove program.

2. Uninstall the network adapter from device manager.

3. Reboot the machine.

4. Login to the machine locally and then setup the network again reboot the VM’s

5. Install the tools and then reboot the VM’s

These steps have to be repeated for all the nodes which will be involved in NLB.

Once this is completed then NLB will be configured without any error.

How to create new "VMDK" desciptor file

Strange issue with the VMDK descriptor file.

One the virtual machine was registered and powered on , but for some reason “vmx” file was missing. I thought I would create a “vmx” file using wizard. I unregistered the “VM” and then tried to create the “vmx” file using wizard. VM was got created but was not able to attached the disk file because “vmdk” descriptor file was missing. “Peewe” how the heck I should create the descriptor file .

1. Tried using other descriptor file from other VM’s and removed the line something like this

RW 419430400 VMFS “rescue_me-flat.vmdk”

This did not work out because the other information like may not be correct.

ddb.virtualHWVersion = “4″
ddb.geometry.cylinders = “26108″
ddb.geometry.heads = “255″
ddb.geometry.sectors = “63″
ddb.adapterType = “lsilogic”
ddb.toolsVersion = “7201″

I was not surprised with this. So I thought lets create a exact same size disk on some other host and copy over the descriptor file from that host to current host (Because current was not having enough space to create the new disk file).

This also did not work because I guess information is so encrypted that I was not able to find out what need to change. So how did I fix it?

1. Power off some other VM’s (In order to free up some space).

2. Once I have enough space create a new disk with same EXACT SIZE using the wizard at the same location where we are trying to create a descriptor file

(This step is very important I wasted my 2 hour to just figure this out)

3. Now remove the newly created disk from the VM.

4. Unregister the VM from the host.

5. Copy the newly created “vmdk” file with the old name (For which we are trying to generate descriptor file).

6. Edit the renamed “vmdk ” file and make sure the entry is pointing to correct flat file

E.g:

# Extent description
RW 419430400 VMFS “rescue_me-flat.vmdk”

7. Once the above steps are done then edit the vmx file and search for the line

E.G

scsi0:0.fileName = " rescue_me-flat.vmdk "

8. Once all the above steps are done then re-register the file using following

Vmware-cmd –s register <path to vmx file>

I would like to thank Paul Shannon for his wonderful blog which really helped me to achieve what I wanted.