New Ubuntu 20.04 with KVM, guest image not able to start/create with Terraform

I have installed Ubuntu 20.04 with KVM and I tried to create Centos 7 guest VM via Terraform.

It is saying "Could not open '/mnt/storage/centos7tes.qcow2': Permission denied", but I tried with root and with user. Also I use Cockpit as GUI.

provider.tf

terraform {
  required_providers {
    libvirt = {
      source = "dmacvicar/libvirt"
    }
  }
}

provider "libvirt" {
  ## Configuration options
  #uri = "qemu:///system"
  #alias = "server2"
  uri   = "qemu+ssh://[email protected]/system"
}

main.tf

# Defining VM Volume
resource "libvirt_volume" "centos7-qcow2" {
  name = "centos7tes.qcow2"
  pool = "default"
  #source = "https://cloud.centos.org/centos/7/images/CentOS-7-x86_64-GenericCloud.qcow2"
  source = "./CentOS-7-x86_64-GenericCloud.qcow2"
  format = "qcow2"
}

# get user data info
data "template_file" "user_data" {
  template = "${file("${path.module}/cloud_init.cfg")}"
}

# Use CloudInit to add the instance
resource "libvirt_cloudinit_disk" "commoninit" {
  name = "commoninit.iso"
  pool = "default" # List storage pools using virsh pool-list
  user_data      = "${data.template_file.user_data.rendered}"
}

# Define KVM domain to create
resource "libvirt_domain" "centos7" {
  name   = "centos7"
  memory = "2048"
  vcpu   = 2

  network_interface {
    network_name = "default"
  }

  disk {
    volume_id = "${libvirt_volume.centos7-qcow2.id}"
  }

  cloudinit = "${libvirt_cloudinit_disk.commoninit.id}"

  console {
    type = "pty"
    target_type = "serial"
    target_port = "0"
  }

  graphics {
    type = "spice"
    listen_type = "address"
    autoport = true
  }
}

# Output Server IP
output "ip" {
  value = "${libvirt_domain.centos7.network_interface.0.addresses.0}"
}

libvirt_volume.centos7-qcow2: Still creating... [40s elapsed]
libvirt_volume.centos7-qcow2: Still creating... [50s elapsed]
libvirt_volume.centos7-qcow2: Still creating... [1m0s elapsed]
libvirt_volume.centos7-qcow2: Still creating... [1m10s elapsed]
libvirt_volume.centos7-qcow2: Creation complete after 1m14s [id=/mnt/storage/centos7tes.qcow2]
libvirt_domain.centos7: Creating...
╷
│ Error: Error creating libvirt domain: internal error: process exited while connecting to monitor: 2021-12-11T23:02:04.400339Z qemu-system-x86_64: -blockdev {"driver":"file","filename":"/mnt/storage/centos7tes.qcow2","node-name":"libvirt-2-storage","auto-read-only":true,"discard":"unmap"}: Could not open '/mnt/storage/centos7tes.qcow2': Permission denied
│ 
│   with libvirt_domain.centos7,
│   on libvirt.tf line 23, in resource "libvirt_domain" "centos7":
│   23: resource "libvirt_domain" "centos7" {

Setting

security_driver = "none"

in /etc/libvirt/qemu.conf and restart libvirtd worked for me to solve a similar problem. (Debian 11, neither AppArmor or SELinux activated / used at all). Error here looked like:

Error: error creating libvirt domain: internal error: process exited while connecting to monitor: ...

and

Could not open '/var/lib/libvirt/images/d1test4-centos7.qcow2': Permission denied

See also https://stackoverflow.com/questions/63984912/coreos-image-fails-to-load-ignition-file-via-libvirt-permission-denied/70563027#70563027