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On 2019/6/14 14:35, Peng Tao wrote:
> By removing the share ram check, qemu is able to migrate
> to private destination ram when x-ignore-shared capability
> is on. Then we can create multiple destination VMs based
> on the same source VM.
> 
> This changes the x-ignore-shared migration capability to
> work similar to Lai's original bypass-shared-memory
> work(https://lists.gnu.org/archive/html/qemu-devel/2018-04/msg00003.html)
> which enables kata containers (https://katacontainers.io)
> to implement the VM templating feature.
> 
> An example usage in kata containers(https://katacontainers.io):
> 1. Start the source VM:
>     qemu-system-x86 -m 2G \
>       -object memory-backend-file,id=mem0,size=2G,share=on,mem-path=/tmpfs/template-memory \
>       -numa node,memdev=mem0
> 2. Stop the template VM, set migration x-ignore-shared capability,
>     migrate "exec:cat>/tmpfs/state", quit it
> 3. Start target VM:
>     qemu-system-x86 -m 2G \
>       -object memory-backend-file,id=mem0,size=2G,share=off,mem-path=/tmpfs/template-memory \
>       -numa node,memdev=mem0 \
>       -incoming defer
> 4. connect to target VM qmp, set migration x-ignore-shared capability,
> migrate_incoming "exec:cat /tmpfs/state"
> 5. create more target VMs repeating 3 and 4
> 
FYI, corresponding kata pull request is posted at 
https://github.com/kata-containers/runtime/pull/1799

Cheers,
Tao
-- 
Into something rich and strange.