Installing Kali Linux as Guest OS in KVM Hypervisor

[Erik Skultety]

On Mon, Dec 07, 2020 at 11:13:08AM +0100, Michal Privoznik wrote:
> On 12/4/20 6:26 PM, Kaushal Shriyan wrote:
> > On Thu, Dec 3, 2020 at 8:54 PM Erik Skultety <eskultet at redhat.com> wrote:
> > 
> > > On Tue, Dec 01, 2020 at 06:15:55PM +0100, Michal Privoznik wrote:
> > > > On 12/1/20 5:28 PM, Kaushal Shriyan wrote:
> > > > > Hi,
> > > > > 
> > > > > I have run the below command to install Kali Linux using
> > > > > linux-2020.4-installer-amd64.iso from https://www.kali.org/downloads/
> > > > > 
> > > > > #virt-install --name kalilinux --memory 4096 --vcpus=2
> > > > > 
> > > --location=/linuxkvmaddgbdisk/kali-linux-2020.4-installer-amd64.iso,kernel=install.amd/gtk/vmlinuz,initrd=install.amd/gtk/initrd.gz
> > > > > --network=bridge:br0 --os-type=linux --os-variant=debian9
> > > --graphics=none
> > > > > --extra-args "console=ttyS0" -v --disk
> > > > > path=/linuxkvmaddgbdisk/kalilinux.img,size=50
> > > > > 
> > > > > I am not able to get the root login prompt when I run the below
> > > command to
> > > > > set IP and hostname for the guest OS. Am I missing any parameters from
> > > the
> > > > > above virt-install command to install Kali Linux as Guest OS in KVM
> > > > > Hypervisor?
> > > > > 
> > > > 
> > > > Just a hunch, maybe --extra-args work only for installation and are not
> > > > persistent? I guess installer doesn't persist kernel cmd line passed in
> > > 
> > > Exactly, --extra-args is just for convenience of not having to edit the
> > > kernel
> > > cmdline manually when the serial console/GUI window opens with grub.
> > > 
> > > Erik
> > > 
> > > 
> > Hi Erik,
> > 
> > Thanks for your reply.  I am not sure if I completely understand it. Is
> > there an issue in the below command? Do I need to remove --extra-args
> > "console=ttyS0" in the below command to have ssh console access to the KVM
> > Guest VM? Please suggest.
> > 
> > #virt-install --name kalilinux --memory 4096 --vcpus=2
> > --location=/linuxkvmaddgbdisk/kali-linux-2020.4-installer-amd64.iso,kernel=install.amd/gtk/vmlinuz,initrd=install.amd/gtk/initrd.gz
> > --network=bridge:br0 --os-type=linux --os-variant=debian9 --graphics=none
> > --extra-args "console=ttyS0" -v --disk
> > path=/linuxkvmaddgbdisk/kalilinux.img,size=50
> > 
> > I look forward to hearing from you. Thanks in Advance.
> 
> For accessing your guest via SSH you do not need a serial console. SSH works
> over network, not serial consoles.
> 
> And those --extra-args: just take virtualization out of the picture for a
> second. You bought yourself a new desktop and want to install a distro onto
> it. You plug an USB stick in and as the installer boots you change the
> kernel cmd line. Then you proceed with installing the distro. I don't think
> that the installer will copy those extra kernel args you added into the
> freshly installed grub, why would it?
> 
> Therefore, when you want to have some extra args after the installation, you
> have to edit the guest. Since at this point you are not booting kernel
> directly, libvirt/qemu can't help you and you need to hand edit grub config
> in the guest. And in this specific case, there is an alternative approach -
> editing /etc/inittab so that the init enables serial console.

Unless that specific Kali version is powered by systemd (which it most likely
is) in which case you're going to see a note in /etc/inittab that it's
deprecated and changes will be ignored. IMO the safest bet here is to edit the
grub config as Michal suggested as the first option.

Regards,
Erik