packer qemu centos7 install hangup

kvm_centos.json

{
  "variables": {
     "iso_os":     "{{env `isoLinux`}}",
     "pkr_http":   "{{env `packerHTTP`}}"
  },  
  "builders": [{
      "boot_command": [
        "<tab> text ks=http://{{ .HTTPIP }}:{{ .HTTPPort }}/centos7.ks<enter><wait>"
      ],  
      "type": "qemu",
      "accelerator": "kvm",
      "boot_wait": "5s",
      "disk_interface": "virtio",
      "disk_size": 40960,
      "format": "qcow2",
      "net_device": "virtio-net",
      "vm_name": "kvmtest",
      "iso_url": "{{user `iso_os`}}/CentOS-7.0-1406-x86_64-DVD.iso",
      "iso_checksum": "ee505335bcd4943ffc7e6e6e55e5aaa8da09710b6ceecda82a5619342f1d24d9",
      "iso_checksum_type": "sha256",
      "output_directory": "packer_kvm",
      "ssh_wait_timeout": "30s",
      "shutdown_command": "reboot",
      "headless": false,
      "http_directory": "{{user `pkr_http`}}",
      "http_port_min": 10082,
      "http_port_max": 10089,
      "ssh_host_port_min": 2222,
      "ssh_host_port_max": 2229,
      "ssh_username": "root",
      "ssh_password": "whatever",
      "ssh_port": 22, 
      "ssh_wait_timeout": "10000s"
    }   
  ]
}