I'm running a server with 16 CPU cores and 128GB RAM on Windows Server 2022, exclusively using Hyper-V. I've set up 9 VMs so far—mostly Ubuntu (22.04 and 24.04 LTS) along with 4 Windows Server 2022 instances, all configured identically and working well. However, when I created my 10th VM (another Ubuntu instance), I started experiencing strange networking issues. The internet traffic on the IT network is inconsistent, only coming in bursts, and I can't reach the VM from the IT address. I've tried deleting and recreating the VM several times, even using a fresh image, but it fails to install during the kernel step—other 24.04 VMs installed without a hitch. I've reconfigured the NICs, but the issues persist. My resources appear adequate as I'm over-allocated with my 16 CPUs, but I'm not sure that's the problem. Any ideas on what could be wrong?
5 Answers
First off, check if the power profile on your Hyper-V host is set to high performance. Sometimes, the default settings can throttle performance unexpectedly.
What does your storage situation look like? Over-provisioning can lead to issues, especially if you're near storage limits. Just double-check that there's enough space available.
Could there be an IP conflict causing the issues? You mentioned all IPs are static, but erratic behavior like that could suggest something isn’t right. It might be worth double-checking.
What’s your networking setup like? Are you using NAT or an external switch? Does this affect access from the Host to the VMs or just from the network? Don’t forget to check your local firewall settings too; try disabling it temporarily to see if it’s interfering with traffic.
Do you have any cloned VMs, or are they all manually created? Also, check if any of your Linux VMs are running on paravirtualized kernels and if the drivers are correctly enabled. It used to cause issues with certain kernels.
No clones here. All VMs were built from scratch, and I'm using full kernels. RAM utilization is around 68%, and I’ve over-allocated vCPUs to about 36 across them.
Yeah, I'd definitely troubleshoot the firewall. It can sometimes act up, especially with multiple VMs.