I have a minimal CentOS 7 installation as a VirtualBox 5.0.16 r105871 guest on a Windows 8.1 host.
uname -r reports "3.10.0-327.10.1.el7.x86_64".
When I try to run
VBoxLinuxAdditions.run I get an error that "The headers for the current running kernel were not found" and suggesting I do
yum install kernel-devel-3.10.0-327.10.1.el7.x86_64. Yet
yum list kernel-devel shows that is already installed (as is
kernel-headers and the appropriate version).
Adding some logging to
vboxadd, I find that it is looking for headers in
/lib/modules/3.10.0-327.10.1.el7.x86_64/build which turns out to be a dead link to a missing
/usr/src/kernels/ is empty.
Googling around suggests that many versions of CentOS require patches to VBGA for the installation to work but I don't see any such notes specific to CentOS 7 or that refer to missing kernel headers.