The Driver Toolkit (DTK) is a container image in the OKD payload which is meant to be used as a base image on which to build driver containers. The Driver Toolkit image contains the kernel packages commonly required as dependencies to build or install kernel modules as well as a few tools needed in driver containers. The version of these packages will match the kernel version running on the RHCOS nodes in the corresponding OKD release.
Driver containers are container images used for building and deploying out-of-tree kernel modules and drivers on container operating systems such as Fedora CoreOS (FCOS). Kernel modules and drivers are software libraries running with a high level of privilege in the operating system kernel. They extend the kernel functionalities or provide the hardware-specific code required to control new devices. Examples include hardware devices like field-programmable gate arrays (FPGA) or graphics processing units (GPU), and software-defined storage solutions, which all require kernel modules on client machines. Driver containers are the first layer of the software stack used to enable these technologies on OKD deployments.