Tuesday, 8 April 2008

Copying VMs

I tried copying my tiny Ubuntu VM, and it ran, except eth0 wouldn't come up, and of course the host name was wrong.

To fix eth0, you have to update /etc/iftab with the new VMWare-generated MAC address for the Ethernet interface. I added a script to the base VM in /usr/local/sbin/changemac to make it easier:

sudo vi /usr/local/sbin/changemac

And add:

mac=`ifconfig -a | grep "HWaddr" | cut -d " " -f 11`

echo "eth0 mac $mac arp 1" > /etc/iftab

Then do:

sudo chmod u+x /usr/local/sbin/changemac

Note that you're adding the script to the "template" VM, so you'll only have create the script once for each template you create, not each time you create a new VM.

Now you can copy the "template" VM. Make sure the "template" VM isn't running. Log in to the VMWare host, change to the directory where you have the VMs, and copy the VM:

cd /usr/local/vmware/Virtual\ Machines
sudo cp -R --preserve=permissions,owner old_VM_directory new_VM_directory

Now in the VMWare console:
  1. Import the new VM and start it.
  2. Log in at the console and run /usr/local/sbin/changemac.
  3. Change /etc/hostname, /etc/dhcp3/dhclient.conf, and /etc/hosts to have the host name you want for the new machine.
  4. Reboot.
I'm sure you should be able to do this without a reboot, but I don't know which startup scripts do what needs to be done. Also, I had some problem with sudo not working after changing /etc/hosts.

If you forget to change the host name in /etc/dhcp3/dhcient.conf the first time around:
  1. Change it
  2. Type sudo date and then enter your password. This is just to make sure that sudo isn't going to prompt you for passwords
  3. Type sudo ifdown eth0 && sudo ifup eth0
The above process will work even if you're on a remote ssh session (e.g. Putty), because the network will go down and up before your terminal times out.

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