How to
$ qemu-img create -f qcow2 ESXi5.5.img 3g Formatting 'ESXi5.5.img', fmt=qcow2 size=3221225472 encryption=off cluster_size=65536 lazy_refcounts=off refcount_bits=16
$ qemu-img info ESXi5.5.img image: ESXi5.5.img file format: qcow2 virtual size: 3.0G (3221225472 bytes) disk size: 196K cluster_size: 65536 Format specific information: compat: 1.1 lazy refcounts: false refcount bits: 16 corrupt: false
Run
qemu-system-x86_64^Crtc base=localtime -m 9000 -bootp tftp://192.168.0.111/gpxelinux.0 -tftp /tftpboot/ /mnt/play/workarea/ESXi5.5.img