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INteresting and amusing things with Virtual Machines

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  • INteresting and amusing things with Virtual Machines

    [I want to be clear: This is NOT for support for VM; if you want VM support, go talk to your vendor. This is about things people have found useful with VM.]

    I've used VMWare products for many years, starting around the late 90s, (1998?/1999? don't remember when, but I seem to recall a beta test described on a Linux mailing list, then a workstation that worked in trial mode) to let me run Windows guest on a VM from inside a Linux host OS. I've played with several of their products, but am still amazed when things work, when outcome is not certain. I've also used Xen, but I don't like them as much.

    First, for VMWare Server 1.0 and VMWare Server 2.0, it was possible to make a VMWare VM using VMWare Workstation, and import to the same relative locations in storage, and then run the workstation-created VM on the "server" VM instance. (I think it was also possible later, to make a VM using a free product like VMWare Server, then export for use with free VMWare client, too.) Additionally, It has been possible for a LONG time to make a new VM using VMWare workstation and then save it to a new machine without VMWare workstation and use a (?still?) free program called "VMWare Client" to "run" that workstation-created VM, but not with all of the same features, (Unity, snapshots, etc.) These were useful.

    Initially, it was more of a toy, but after two or three years, my employer paid for all this software so there is no need to find kludgey ways to get away with not paying to use this software. (Not pirating, just exploiting free versions of software that could be used to make VM, and other free software that could run VM that were made by other software.)

    Later, for research, use of snapshots and connections of VM to debuggers have both been useful.

    I recently ran into two minor problems, and wanted to provide a comment on these for anyone else to consider as solutions.

    First, I created a Windows XP VM for running as a guest on my LInux Host OS, but did not allocate enough disk space. Disk was formatted as NTFS, and OS was Windows XP. 20 GB was not enough. When guest was shut down, it was possible to "Expand disk" but this only enlarged the physical disk presented to the OS, and did no filesystem expansion. Historically, on a non-VM, I would try PartitionMagic, or parted, but this was a VM, and who knows if those would work as expected. From VM (Windows XP) performed "ChkDisk", defrag, then ChkDisk again. Then shutting down XP and booting from an Ubuntu ISO as disk image for CD/DVD drive to this Windows VM, then using Ubuntu in live trial (no install on disk) gparted was able to resize this VM's NTFS filesystem for XP on the VM's virtual disk. Pretty cool. Was not sure that work work, and am glad it did.

    Next problem: in playing with ESXi using vSphere client, I attempted to leverage my previous experience with making VM with workstation and then import into this vmware server (ESXi) maintaining the same relative VM locations were installed on the workstation, but this did not work. A short search of the error reported when viewing logs using vSphere showed that the VM virtual disk and VM information for Workstation was different from ESXi, and an exchange/conversion tool was required. VMWare "Converter Standalone Client" (free, as in beer) did this. From within a VM running windows, and access to a samba share to network disk on host-OS, I was able to "show" this application my local host OS VM from within another VM running as a guest, and then give it the same credential used with vSphere to connect to the ESXi, and from windows guest, was able to convert another Linux VM for use with the ESXi server, and upload it to that ESXi server.

    I do not work for VMWare, but wanted to share 2 things that I found useful this weekend when working with their products.

    Do you have other things you have found useful with VMware VM, or maybe xen VMs or other VM?
    Last edited by TheCotMan; July 3, 2011, 01:15.

  • #2
    Re: INteresting and amusing things with Virtual Machines

    The SCADA software that I had been using, the License for the software was somehow tied directly into the hardware of the machine. Change out the motherboard of the machine and all the sudden your license is gone. If your support agreement was registered under the system integrator's name instead of your company's name, you never got the notice that your support contract had expired and now you're up shit crick because you have to get the machine back up and running.

    I had started doing testing with using a VM for the SCADA servers. Testing was pretty positive when I left there. But it was a perfect way to solve the problem. If you'd tie the license into the VM, it wouldn't matter anymore what hardware it was running on.
    A third party security audit is the IT equivalent of a colonoscopy. It's long, intrusive, very uncomfortable, and when it's done, you'll have seen things you really didn't want to see, and you'll never forget that you've had one.