Qemu how to get a port for VNC and stop the terminal?

January 11, 2022

Using Ubuntu 20.04, I am starting my Ubuntu server with:

qemu-system-x86_64 \
  -enable-kvm \
  -cpu host \
  -smp 11 \
  -drive format=raw,file=/mnt/kvm-guests/work.img,if=virtio \
  -net nic,model=virtio,macaddr=ec:8d:2c:f3:2a:7c \
  -net tap,ifname=tap2,script=no,downscript=no \
  -runas kvmuser \
  -nographic \
  -m 30000 &

How do I make it to where:

There is a port given in the output if I want to vnc into it
Not have the terminal be used as a display (I don’t want a terminal at all)

Using Qemu version 4.2.1 along with KVM

>Solution :

for the cli configuration of a VNC you need to configure the display that way.
To do that drop "nographic" and instead add something like -display none -vnc :0.

Of these options -display none makes it not put output somewhere immediately, but in comparison to nographic it will leave a virtual gpu present to the guest. Then -vnc controls where/how to open a port. There are many suboptions, and I’d recommend to restrict accessibility and authentication. You can aslo combine it with spice, so I’d recommend to have a look for "vnc" in the man page

-display none of the above will already have done that for you, for full background execution consider also adding-daemonize