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Weird Network slowness on qemu vms

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nitgeek

I've created two qemu VMs using below command. Both VMs are on virbr0 bridge.

qemu-system-x86_64 \
  -drive "file=bionic-server-cloudimg-amd64.img,format=qcow2" \
  -drive "file=${user_data},format=raw" \
  -device rtl8139,netdev=net0 \
  -enable-kvm \
  -m 2G \
  -netdev bridge,br=virbr0,id=net0 \
  -serial mon:stdio \
  -smp 2 \
  -vga virtio;

IP of first vm is 192.168.122.76 and for second one is 192.168.122.77

Wierd network issue is, if I do an ssh to vm-1 it will be fast and instantly I will be asked for password. Then I try ssh to vm-2 and it takes about 20 seconds for the password prompt to appear. Then I again try ssh to vm-2 and it instantly asks for password. Next I do ssh to vm-1 and I notice about 20 seconds before it shows password prompt.

In short, whichever IP I used last connects instantly and the other one responds after a long delay.

The I ran same hello world application on both VMs exposed on same port, port 8080. Then I see the same behaviour with the curl as well I get instant response when I curl the same IP again. And if I move from one IP to other, it again gives a delayed response.

I am using bionic-server-cloudimg-amd64 image for VM and Ubuntu 21.10 is my host machine which is running as a VMWare Fusion VM on a Mac.

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