[Reference] vsock NFS support

[gnawux]

NFS via vsock is under developing, and is promising for the future FS sharing of hyper, because:

• NFS has much better performance/feature set than 9p
• vsock doesn't need to add a network interface to guest, and then doesn't setup a network connection between host and guest, i.e. better isolation than open a network connection to every guest.
• and it may also substitute the virt-serial for communication

Some blocker of adopting vsock NFS

• the tool set is under developing:
• the xen doesn't support vsock yet, i mean xenbus based transport, once it is supported xenbus, we can use it to provide FS sharing in PV mode.

Some references:

• The initial patch set: https://lwn.net/Articles/647516/
• Slides: http://events.linuxfoundation.org/sites/events/files/slides/stefanha-kvm-forum-2015.pdf
• qemu wiki: http://qemu-project.org/Features/VirtioVsock

Related repos:

• kernel, vsock-nfs: https://github.com/stefanha/linux/tree/vsock-nfs
• user space tools: https://github.com/stefanha/nfs-utils
• qemu vsock support: https://github.com/stefanha/qemu/tree/vsock

[gnawux]

update the xen vsock support status

design in 2013:

• mailing list: http://lists.xenproject.org/archives/html/xen-devel/2013-06/msg01123.html
• pdf: http://xenbits.xen.org/people/dvrabel/inter-domain-comms-C.pdf

[gnawux]

update: manila project will adopt vsock-nfs to introduce cephfs to guest

[laijs]

A update slides: http://vmsplice.net/~stefan/stefanha-connectathon-2016.pdf

[bergwolf]

update: nfs-ganesha support for vsock: https://github.com/nfs-ganesha/nfs-ganesha/commit/c2d6ca82f61c4014daca96df63b251a67a3b0488

It is queued for nfs-genasha v2.4 that is still under development right now.

[laijs]

hyperstart goes into the maintaining-only state. Could you move this issue to kata-agent? @gnawux @bergwolf