* Tao Peng (bergwolf@hyper.sh) wrote:
On Tue, Dec 11, 2018 at 3:25 AM Stefan Hajnoczi <stefanha@redhat.com> wrote:
Hi Stefan,
Dear Kata Containers Community, I'm delighted to announce the first release of virtio-fs, a new shared file system for virtual machines that is designed for container use cases, including shared volumes.
Unlike virtio-9p and NFS over AF_VSOCK, virtio-fs aims to take advantage of the co-location between the virtual machine and the hypervisor in order to achieve local file system semantics and improve performance.
For example, it can use Linux Direct Access (DAX) to access file contents directly from the host page cache. This reduces communication with the file server and avoids duplicating data into each sandbox VM. It also means that mmap MAP_SHARED on a shared volume is coherent between sandbox VMs.
The Linux kernel code (including performance numbers) has been posted here: https://marc.info/?l=linux-fsdevel&m=154446243324255&w=2
Excellent! Both performance and POSIX compliance look just as promised. It's a good replacement for 9pfs and indeed very suitable for kata containers.
Kata Containers integration is already available so you can benchmark and test virtio-fs. The project is under active development and we still expect to make significant changes based on feedback and collaboration.
We hope virtio-fs is interesting as a next step in overcoming virtio-9p's performance and limitations. Let us know how it performs!
You can read more about virtio-fs here: https://virtio-fs.gitlab.io/
The Kata HowTo is here: https://virtio-fs.gitlab.io/howto-kata.html
The Kata runtime and agent changes are fairly straightforward and comparable to virtio-9p. There are several other code changes due to using a Fedora initramfs, systemd, and modular kernel. These are not essential to virtio-fs but are simply how I preferred to develop and test.
Could you please send these changes on github so that we can properly review and get them merged? Please separate preparation patches as they can be merged before virtio-fs is mergeable. Thanks!
The FAQ on the virtio-fs website explains the main technical features. Please let me know if you have any questions or need help getting it running! I'm also on #kata-dev IRC if you need a hand.
I tried to follow the instructions on the virtio-fs website and got stuck at cloning https://gitlab.com/virtio-fs/qemu.git. It seems to be private atm?
Oops, missed that one; fixed! Dave
Cheers, Tao -- bergwolf@hyper.sh -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK