{
  "builders": [{
    "vm_name": "packer-rhel7",
    "type": "vmware-iso",
    "iso_url": "rhel-workstation-7.1-x86_64-boot.iso",
    "iso_checksum": "b6c57194130025cecc036676d43235508f4031d99041051ea1c61e259bd95903",
    "iso_checksum_type": "sha256",
    "output_directory": "packer_rhel_7",
    "ssh_username": "root",
    "ssh_wait_timeout": "60s",
    "shutdown_command": "shutdown -P now",
    "headless": "false",
    "tools_upload_flavor": "linux",
    "tools_upload_path": "/tmp/vmare_tools_linux.iso",
    "boot_wait": "5s",
    "boot_command": [
      "<tab> text ks=http://{{ .HTTPIP }}:{{ .HTTPPort }}/ks_cloud.cfg<enter><wait>"
    ]
  }]
}


{
  "builders": [{
    "vm_name": "packer-rhel7",
    "type": "vmware-iso",
    "iso_url": "rhel-workstation-7.1-x86_64-boot.iso",
    "iso_checksum": "b6c57194130025cecc036676d43235508f4031d99041051ea1c61e259bd95903",
    "iso_checksum_type": "sha256",
    "output_directory": "packer_rhel_7",
    "ssh_username": "root",
    "ssh_wait_timeout": "60s",
    "shutdown_command": "shutdown -P now",
    "headless": "false",
    "tools_upload_flavor": "linux",
    "tools_upload_path": "/tmp/vmare_tools_linux.iso",
    "boot_wait": "5s",
    "boot_command": [
      "<tab> text ks={{user `kickstart_file_url`}}<enter><wait>"
    ]
  }]
}


Use variables for kickstart parameter.
Use variables for kickstart parameter.
