Re: [Qemu-devel] [RFC PATCH 0/9] Add colo-proxy based on netfilter

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Zhang Chen (zhangchen.fnst@cn.fujitsu.com) wrote:
> 
> Hi,all
> 
> This patch add an colo-proxy object, COLO-Proxy is a part of COLO,
> based on qemu netfilter and it's a plugin for qemu netfilter. the function
> keep Secondary VM connect normal to Primary VM and compare packets 
> sent by PVM to sent by SVM.if the packet difference,notify COLO do
> checkpoint and send all primary packet has queued.
> 
> You can also get the series from: 
> 
> https://github.com/zhangckid/qemu/tree/colo-proxy-V1
> 
> Usage:
> 
> primary:
> -netdev tap,id=bn0 -device e1000,netdev=bn0
> -object colo-proxy,id=f0,netdev=bn0,queue=all,mode=primary,addr=ip:port
> 
> secondary:
> -netdev tap,id=bn0 -device e1000,netdev=bn0
> -object colo-proxy,id=f0,netdev=bn0,queue=all,mode=secondary,addr=ip:port

If we have more than one NIC on the guest, do you intend to allow
multiple colo-proxy's ?

Having read through the series, it looks like the main missing piece
is the work to synchronise sequence numbers.

I think also you'll need to clean out the connection hash when either
you see both sides have closed the connection or (maybe after some
time of idleness as well? Otherwise we'd just accumulate dead connections
overtime).

I'm guessing the buffer filter also has to be created on the command line?
How does the order of buffers work?

Dave

> 
> NOTE:
> queue must set "all". See enum NetFilterDirection for detail.
> colo-proxy need queue all packets
> colo-proxy V1 just a demo of colo proxy,not pass test with colo upstream
> 
> 
> ## Background
> 
> COLO FT/HA (COarse-grain LOck-stepping Virtual Machines for Non-stop Service)
> project is a high availability solution. Both Primary VM (PVM) and Secondary VM
> (SVM) run in parallel. They receive the same request from client, and generate
> responses in parallel too. If the response packets from PVM and SVM are
> identical, they are released immediately. Otherwise, a VM checkpoint (on 
> demand)is conducted.
> 
> Paper:
> http://www.socc2013.org/home/program/a3-dong.pdf?attredirects=0
> 
> COLO on Xen:
> http://wiki.xen.org/wiki/COLO_-_Coarse_Grain_Lock_Stepping
> 
> COLO on Qemu/KVM:
> http://wiki.qemu.org/Features/COLO
> 
> By the needs of capturing response packets from PVM and SVM and finding out
> whether they are identical, we introduce a new module to qemu networking 
> called colo-proxy.
> 
> 
> v1:
>  initial patch.
> 
> 
> 
> zhangchen (9):
>   Init colo-proxy object based on netfilter
>   jhash: add linux kernel jhashtable in qemu
>   colo-proxy: add colo-proxy framework
>   colo-proxy: add colo-proxy setup work
>   net/colo-proxy: add colo packet handler
>   net/colo-proxy: add packet forward function
>   net/colo-proxy: add packet enqueue and handle function
>   net/colo-proxy: enqueue primary and secondary packet
>   net/colo-proxy: add packet compare and notify checkpoint
> 
>  include/qemu/jhash.h |  52 ++++
>  net/Makefile.objs    |   1 +
>  net/colo-proxy.c     | 745 +++++++++++++++++++++++++++++++++++++++++++++++++++
>  net/colo-proxy.h     | 124 +++++++++
>  qemu-options.hx      |   4 +
>  vl.c                 |   3 +-
>  6 files changed, 928 insertions(+), 1 deletion(-)
>  create mode 100644 include/qemu/jhash.h
>  create mode 100644 net/colo-proxy.c
>  create mode 100644 net/colo-proxy.h
> 
> -- 
> 1.9.1
> 
> 
> 
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK