libvirt users - Nov 2019 - Understanding the use of virt-install from the CLI (Linux)

On Thu, 7 Nov 2019, jonetsu wrote:
> And it reports:
>
> 'Size must be specified for non existent volume
'arch01.qcow2''
>
> But the size is already specified as one of the options.
At least the following works on Debian 10:

virt-install \
  --connect "qemu:///session" \
  --name "debian10virt-install" \
  --ram "1024" \
  --vcpus "1" \
  --disk
"size=20,path=$HOME/.local/share/libvirt/images/debian10virt-install.qcow2,bus=scsi,cache=none,discard=unmap"
\
  --controller "type=scsi,model=virtio-scsi" \
  --initrd-inject "preseed.cfg" \
  --initrd-inject "late_command.sh" \
  --location
"http://deb.debian.org/debian/dists/buster/main/installer-amd64/" \
  --os-type "linux" \
  --os-variant "debian9" \
  --virt-type "kvm" \
  --controller "usb,model=none" \
  --graphics "none" \
  --network "user,model=virtio" \
  --noreboot \
  --extra-args "auto=true hostname=debian domain= console=ttyS0,115200n8
serial"

Source: https://lindi.iki.fi/lindi/debian10/virt-install/install.bash


-Timo

Hello,

I've created several VMs using virt-manager and am using them.  This
time around though, I'd like to use the CLI approach.  The problem
resides in defining a storage space.  This is using virt-install 1.5.1
on Xubuntu 18.04.

For the occasion I created a new directory to store images.  So I
specify this new directory:

virt-install \
--name=arch01 \
--disk path=/Share2/KVMImages/arch01.qcow2 \
--disk size=10 \
[ ... ]

The above will not work as it reports:

'must be a file or a device, not a directory'

So I specify a file:

[ ... ]
--disk path=/Share2/KVMImages/arch01.qcow2 \
--disk size=10 \
[ ... ]

And it reports:

'Size must be specified for non existent volume 'arch01.qcow2''

But the size is already specified as one of the options.

This is where I'm puzzled about the process.  What is going on ?

On Thu, Nov 07, 2019 at 11:02:49AM -0500, jonetsu wrote:
> Hello,
> 
> I've created several VMs using virt-manager and am using them.  This
> time around though, I'd like to use the CLI approach.  The problem
> resides in defining a storage space.  This is using virt-install 1.5.1
> on Xubuntu 18.04.
> 
> For the occasion I created a new directory to store images.  So I
> specify this new directory:
> 
> virt-install \
> --name=arch01 \
> --disk path=/Share2/KVMImages/arch01.qcow2 \
> --disk size=10 \
> [ ... ]
> 
> The above will not work as it reports:
> 
> 'must be a file or a device, not a directory'
> 
> So I specify a file:
> 
> [ ... ]
> --disk path=/Share2/KVMImages/arch01.qcow2 \
> --disk size=10 \
> [ ... ]
> 
> And it reports:
> 
> 'Size must be specified for non existent volume
'arch01.qcow2''
> 
> But the size is already specified as one of the options.
> 
> This is where I'm puzzled about the process.  What is going on ?

Hi,

The issue is that you are using the virt-install --disk option
incorrectly. If you look into man page of virt-install you can see some
examples.  The options for each parameter needs to be separated by
comma.  The command line that you are using is telling virt-install to
use 2 disks, one with the path and second one with only size provided.

If you want to have only a single disk for your VM you need to use it
like this:

virt-install \
    [ ... ] \
    --disk path=/Share2/KVMImages/arch01.qcow2,size=10 \
    [ ... ]

Pavel

On Thu, 7 Nov 2019 17:52:32 +0100
Pavel Hrdina <phrdina@redhat.com> wrote:
> The issue is that you are using the virt-install --disk option
> incorrectly. If you look into man page of virt-install you can see
> some examples.  The options for each parameter needs to be separated
> by comma.  The command line that you are using is telling
> virt-install to use 2 disks, one with the path and second one with
> only size provided.
Thanks.  That was it.  I completely forgot that it's possible to specify
a x number of disks.

On Thu, 7 Nov 2019 16:44:45 +0200 (EET)
Timo Lindfors <timo.lindfors@iki.fi> wrote:
> At least the following works on Debian 10:
Thanks.  That's quite a few options to read about.  One question: what
is the pressed.cfg about ?  Is it to seed the rng early in the install
process ?