mount qcow2 from rhel7

method 1 
install packages
  yum install libguestfs-tools

start libvirtd service
  systemctl start libvirtd

find device name presented in qcow2 image
  guestmount -a rhel-server-7.4-x86_64-kvm.qcow2 -m /dev/xxxxxx --ro /mnt/test/

======================================================
guestfsd: main_loop: proc 272 (part_to_dev) took 0.00 seconds
guestfsd: main_loop: new request, len 0x38
commandrvf: stdout=y stderr=y flags=0x0
commandrvf: blkid -c /dev/null -o value -s TYPE /dev/sda1
guestfsd: main_loop: proc 198 (vfs_type) took 0.08 seconds
guestfsd: main_loop: new request, len 0x28
commandrvf: stdout=y stderr=y flags=0x0
commandrvf: lvm lvs --help
  Invalid units specification
guestfsd: error: lvm lvs --help:   Invalid units specification
guestfsd: main_loop: proc 11 (lvs) took 0.09 seconds
libguestfs: error: lvs: lvm lvs --help:   Invalid units specification
libguestfs: closing guestfs handle 0x7fc753c248e0 (state 2)
guestfsd: main_loop: new request, len 0x28
======================================================

mount image
  guestmount -a rhel-server-7.4-x86_64-kvm.qcow2 -m /dev/sda1 --ro /mnt/test/

method 2
install packages
  yum install libguestfs-tools

convert qcow2 image to raw disk format

  qemu-img convert xxx.qcow2 xxx.raw

list partition layout

  fdisk -l xxx.raw

mount drive

  mount -o offset=$((BLOCK_SIZE * START_BLOCK)) xxx.raw /MNT_POINT

ex:

  mount -o offset=$((512 * 2048)) xxx.raw /mnt/