Communicating with the Guest Os before the network comes up.

[Ligesh <xen@lxlabs.com>]

 Hi folks,

  I would like to know if it is possible to add a mechanism to send a simple string into the Virtual Machine. For instance, in the case of Vmware, we can define a variable called as machine.id in the config file, and this can be accessed from inside the VM using the /etc/vmware/vmware-guestd on linux or VmwareService.exe on Windows. The main purpose of this is to setup static ip address for the Virtual Machine. What you do is:


  In the config file you define the variable:
  ----------
  machine.id = "Mtx <ipaddress>"
  ----------


  Now from inside the VM you can acess this machine.id by executing vmware-guestd

  ----------------
  $string = `vmware-guestd --cmd machine.id.get`
  $ip = `echo $string | cut -f 1`
  ifconfig eth0 $ip
  ----------------

 This is portable across platforms, and would actually help a lot in the management of the VM. Now, as far as remote management is concerned, we have to depend on the network to have any type of interaction with the VM, which is a serious limitation. With this mode, it becomes sort of a backup, since a wide variety of commands can be passed to a daemon that will start at the bootup. For instance, you can ask it to execute an arbitrary command at the bootup using this method, which can help in recovering the machine in case one of the network services fails.

 Thanks.
 
--
:: Ligesh :: http://lxlabs.com