Re: [gentoo-user] virtualbox in headless configuration broken after update: delayed echo [ RESOLVED, kinda ]

[Michael]

On Wednesday, 17 June 2020 20:55:19 BST J. Roeleveld wrote:
> On 17 June 2020 21:32:19 CEST, Michael <confabulate@××××××××.com> wrote:

> This brings another problem I have with KVM/QEMU: all howtos and documents I
> find show long commandline options to just start the VM. I have not found
> one where I can provide all the config in a single file and use that.
> Allowing me to duplicate settings by simply copying the file and changing a
> few lines.
>
> KVM/Qemu seems to be written to be used together with virt-manager which,
> for me, lacks important features to make it usable in production.
>
> --
> Joost

The long line can be extremely short, if you are happy with defaults, or 
silly-long if you have specific needs.  The same long line can also go into a 
script and invoked with bash.  For example, this will boot a pfSense VM on an 
EFI BIOS platform, 4G RAM and Opteron_G5-v1 CPU:

qemu-system-x86_64 -bios /usr/share/edk2-ovmf/OVMF_CODE.fd -m 4096 -cpu 
Opteron_G5-v1,+topoext -smp cpus=4,maxcpus=8,cores=4,threads=2,sockets=1 -
enable-kvm -accel kvm,thread=multi -display sdl,gl=on -vga virtio -soundhw hda 
-drive if=virtio,file=pfSense.qcow2,cache=none -usb -device qemu-xhci,id=xhci 
-net nic,model=virtio -net user,hostfwd=tcp::53260-:443

or, you could set it all up in a script file, one or more lines at a time:

#!/bin/bash
#
        qemu-system-x86_64 \
        -bios /usr/share/edk2-ovmf/OVMF_CODE.fd \
        -m 4096 \
        -cpu Opteron_G5-v1,+topoext \
[snip ...]

Then call the script from a terminal whenever you want to run it.  I prefer 
using a script file when I experiment with new machines and options, because 
it allows me to comment out options as I change them to alternatives and 
backtrack as necessary.

If you prefer to use RHL's libvirt to execute in 'C' API calls onto QEMU/KVM, 
then virt-manager will offer a VirtualBox GUI equivalent, or virsh a CLI 
option.  Virt-manager can be the front end for other hypervisors/VMs, e.g. 
Xen, ESX, etc. so it is not QEMU/KVM specific.

QEMU also offers QMP for JSON scripting, because ... apps, and a rather basic 
console interface called Human Monitor Interface (HMP), should you wish to 
interact with it while it's running to modify inputs/interfaces, plug/unplug 
devices, etc.

I'm not starting and stopping VMs all day long, so installing and running a 
libvirt GUI, or some of the various front ends for QEMU has not been necessary 
for me.  However, they may offer more sophisticated options than my basic CLI 
input above.