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NEW
- Add support for GPU-enabled kernels (using
[nvidia-docker plugin](https://github.com/NVIDIA/nvidia-docker)).
The kernel images must be built upon nvidia-docker's base Ubuntu images and
have the label "io.sorna.nvidia.enabled" set `yes`.
CHANGES
- Change the agent to add "lablup/" prefix when creating containers from
kernel image names, to ease setup and running using the public docker
repository. (e.g., "lablup/kernel-python3" instead of "kernel-python3")
- Change the prefix of kernel image labels from "com.lablup.sorna." to
"io.sorna." for simplicity.
- Increase the default idle timeout to 30 minutes for offline tutorial/workshops.
- Limit the CPU cores available in kernel containers.
It uses an optional "io.sorna.maxcores" label (default is 1 when not
specified) to determine the requested number of CPU cores in kernels, with a
hard limit of 4.
NOTE: You will still see the full count of CPU cores of the underlying
system when running `os.cpu_count()`, `multiprocessing.cpu_count()` or
`os.sysconf("SC_NPROCESSORS_ONLN")` because the limit is enforced by the CPU
affinity mask. To get the correct result, try
`len(os.sched_getaffinity(os.getpid()))`.