I already done on digitalocean some time ago and in vmware:
See my notes here: https://gist.github.com/braian87b/a7db0b0a9e79fbbec9a478def05f9161
Download DamnSmallLinux from here: ftp://distro.ibiblio.org/pub/linux/distributions/damnsmall/current/ # dsl-4.4.10.iso
Minimum requirements:
RAM: 32mb, HardDisk: 52mb (for OpenWRT, for LEDE try to use much more)
Linux Kernel: 2.6.x ó 3.x 32bits
Disk type: IDE, Ethernet E1000
More about this on: http://wiki.openwrt.org/doc/howto/vmware