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    VM Failing to Reboot

    Scheduled Pinned Locked Moved Unsolved Management
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    • D Offline
      dinhngtu Vates 🪐 XCP-ng Team @kagbasi-ngc
      last edited by dinhngtu

      @kagbasi-ngc said in VM Failing to Reboot:

      I tried the command against the {default} identifier, and it worked. However, I didn't see any change in behavior during the boot process. Should I continue with the instructions for exposing the VMs serial console?

      Yes, it won't show anything special on screen during boot, but attaching a debugger should work if everything is configured correctly. Note that it's timing dependent (there's a small time window where you can attach before it reaches the BSOD) so it might take a few tries.

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      • K Offline
        kagbasi-ngc @dinhngtu
        last edited by

        @dinhngtu Roger that, I'll try it now and see what happens.

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        • K Offline
          kagbasi-ngc @kagbasi-ngc
          last edited by

          @dinhngtu While following the instructions you shared on how to expose the VM's serial console, I'm having trouble with this command "bcdedit /dbgsettings serial debugport:1 baudrate:115200". I had to modify it slightly to specify the /store parameter (as indicated previously).

          Since I don't have the ability to run this command inside the OS, I am running it from a command shell that I accessed via the Troubleshooting menu (from an installation disk). It accepted the first command "bcdedit /store S:\EFI\Microsoft\Boot\BCD /set {default} debug on" but won't accept "bcdedit /store S:\EFI\Microsoft\Boot\BCD /set {default} dbgsettings serial debugport:1 baudrate:115200". It throws the following error:

          The element data type specified is not recognized or does not apply to the specified entry.

          What am I missing here?

          Second issue - I attempted to get the host ready by setting the parameters (as per the instructions) and opened the firewall port (I used 7001). However, when I attempt to connect to the host via SSH on tcp\7001, the connection is refused.

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          • D Offline
            dinhngtu Vates 🪐 XCP-ng Team @kagbasi-ngc
            last edited by

            @kagbasi-ngc You'll need these commands instead:

            bcdedit /store bcd /set {dbgsettings} debugtype serial
bcdedit /store bcd /set {dbgsettings} debugport 1
bcdedit /store bcd /set {dbgsettings} baudrate 115200

            The serial port is only accessible when the VM is running.

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            • K Offline
              kagbasi-ngc @dinhngtu
              last edited by

              @dinhngtu Thank you for breaking it down, this worked and I was able to get the commands to be accepted on the VM. Whether they actually took effect, I can't tell.

              Here's what I observed:

              • I prepped the host with the xe vm-param-set uuid=<uuid> platform:hvm_serial=tcp::<port>,server,nodelay,nowait command and opened the firewall (using tcp port 7001).

              • I disabled Secure Boot on the VM, prepped a PuTTY session to connect to my host on TCP port 7001

              • I noticed that whenever the VM starts booting, and I simultaneously initiate the putting session, it seems like a connection is made but no data is returned to the screen. The session terminates as soon as the VM runs into the BSOD and shuts down.

              I recorded a video of it: https://photos.app.goo.gl/wzJSwfoJJJWwtGk57

              Next thing with Windbg. This is my first time using it, so please pardon my ignorance. However, I am unable to attach to the kernel debug, as per the instructions you provided. I see a Kernel Debug menu item and when I click on it, I don't see any place where I can enter the connection string specified in the instructions you provided.

              Here's another video capture: https://photos.app.goo.gl/ZnjVQjo5Hk589dQ96

              We're making progress, and I really appreciate your patience, thank you.

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              • D Offline
                dinhngtu Vates 🪐 XCP-ng Team @kagbasi-ngc
                last edited by dinhngtu

                @kagbasi-ngc That's the old WinDbg. You should use the new WinDbg instead: https://learn.microsoft.com/en-us/windows-hardware/drivers/debugger/
                windbggetstart01.png

                The serial connection looks to be working.

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                • D Offline
                  dinhngtu Vates 🪐 XCP-ng Team @kagbasi-ngc
                  last edited by

                  @kagbasi-ngc More instructions for you on how to use WinDbg:

                  In WinDbg, select File - Attach to kernel - Paste connection string and paste in your connection string. Once the debugger finishes attaching, click Go until WinDbg says "BUSY Debuggee is running", then wait until the VM crashes. You should see an error message (see screenshot).

                  Click the "!analyze -v" link, it will spit out a bunch of analysis info. This will take a while. Once it's done, paste the entire WinDbg output counting from the initial "Fatal System Error" message, including the entirety of the analysis output.

                  377679f4-3ade-4593-af0b-f9da917d90d0-image.png

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                  • K Offline
                    kagbasi-ngc @dinhngtu
                    last edited by

                    @dinhngtu Thanks for the instructions. I'm back in the lab now, and I'm going to try as you've suggested.

                    Because the lab is airgapped (disconnected from the Internet), I wasn't able to install the latest version of Windbg, which is why I opted to use the version from the Windows SDK ISO. I need to figure out how to get the latest Windbg installed in an offline system, then I'll be able to proceed.

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                    • D Offline
                      dinhngtu Vates 🪐 XCP-ng Team @kagbasi-ngc
                      last edited by

                      @kagbasi-ngc Try this method: https://xcp-ng.org/forum/post/85097

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                      • K Offline
                        kagbasi-ngc @dinhngtu
                        last edited by

                        @dinhngtu Thanks, that helped. Download has started, once it completes, I'll get it installed and retry.

                        I'd also found this - https://gist.github.com/alexrintt/9502728c6d75d27e2885c9cdaab0e550

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