Azure VM Cannot Connect Except via Serial Console

Question

The VM is a Windows 2016 Server. The machine was rebooted and after 4 hours it was still "restarting." Stopped the machine and then started it. Boot diagnostics screenshot showed it was at the login screen and had the correct time. Cannot ping the VM or access via RDP. I was able to access using the serial console. From there, I checked the IP address (it was correct). I also tried pinging other machines within Azure and on-prem. All worked! Opened RDP and ICMP ports on the network interface (these things worked before, but I set the explicit rules). Still, I only have access to the serial console / command.

Note that this machine was built to replace another Windows 2016 Server VM that was stuck "restarting." It eventually went into a reboot loop w/ BSODs. It feels like I could be heading down the same path...

Any help is appreciated!

Answer 1

Hi @KBFZ ,

Try starting a CMD or PowerShell session through Serial Console, if it doesn't allow those sessions to start, or they disconnect immediately then it's likely reboot looping.

• Serial Console Sessions: https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/serial-console-windows#use-cmd-or-powershell-in-serial-console

If this image was pulled from a VM that was experiencing a reboot loop or start failure, then it's likely still malfunctioning. You may need to pull it offline/ into Nested Virtualization on another Virtual Machine to repair, or pull the data you need into a clean image. It's a good idea to pull the OS Drive/Image into a Nested VM just to review integrity and see if it is actually reboot looping.

If you're concerned that RDP may just be misconfigured then you can reset RDP Configuration and restrict the Network Security Group to only allow your IP range.

• Reset RDP: https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/reset-rdp
• Repair VM + Reboot Loop: https://learn.microsoft.com/en-us/troubleshoot/azure/virtual-machines/troubleshoot-reboot-loop

Answer 2

I was able to able to access command after I stopped the machine from the portal and restarted. I could ping from the machine, but other machines could not ping it. I don't think RDP is misconfigured as that is how I accessed it to do the initial reboot. I will try resetting RDP.

The machine was built with a new image from Azure.

Since my post, I tried rebooting again. It has been going for 5 hours. I'm going to leave it run overnight. If it is still "restarting" in the morning I will go through the repair stuff, but I did that with it's predecessor and nothing worked.

Actually, I can still access the command window, but I am unable to authenticate using the domain login I used to start the session. I cannot run any additional commands without authenticating and I have no opportunity to change the user or domain. Do you know a way to end the command session or reset it so I can try a local login? I'd like to try to create a dump file while it is trying to reboot.

Thanks for you help!