Re: Documentation for KVM/QEMU?

[Stanislav Vlasov <stanislav.v.v@gmail.com>]

2023-11-06 12:45 GMT+05:00, Michael Kjörling <2695bd53d63c@ewoof.net>:
> The three biggest differences I have run across (I used VirtualBox
> before):
>
> 1. Storage pools for disk images. With VirtualBox, you can put a disk
> image file anywhere. With KVM, they go into one of a defined set of
> pools, which in turn map to file system directories. Depending on what
> kind of setup you prefer, this can be anything from actually
> beneficial through a non-issue to a nuisance.

I run qemu binary with parameters and place disk image in any place
and can use any physical disk as qemu image, if need.
In old scripts it was something like:

qemu-system-x86_64 -m 1024M -hda /path/disk.img -cdrom
/another/path/image.iso -boot cdrom

So, it is not qemu, only your gui wrapper/interface limitation.

> 3. KVM virtualized NAT networking doesn't play nice with nftables on
> the host with a restrictive policy. Took me a while to find a solution
> but I eventually came up with this, which has worked reliably for me:
> https://michael.kjorling.se/blog/2022/linux-kvm-host-nftables-guest-networking/

this is not qemu/kvm thing, only libvirt, which is not part of qemu,
but only wrapper on it. Sometimes useful, good for beginning, bad, if
you need something non-standard.

qemu as virtual machine does not create/use firewall rules at all and
can use user mode net, which work without firewall rules — see man
qemu for -net parameter (use -net nic -net user if you need only
output network requests).

-- 
Stanislav