Are you building on a system that is not Ubuntu Xenial 16.04? If you are then you will need to either create a virtual machine with Ubuntu Xenial 16.04 for the build, or use LXD (using LXD is currently the strongly recommended method).
Are you building on a system that is not Ubuntu Xenial 16.04? If you are then you will need to either create a virtual machine with Ubuntu Xenial 16.04 for the build, or use LXD (using LXD is currently the strongly recommended method).