On Tue, Oct 16, 2012 at 12:51:23AM +0800, Xu He Jie wrote:
> [SNIP]
> Hi, Adam, Could you explain more detail about how streaming API can
> survive a VM migration?
> If we want to support migration, I think we should implement console
> server out of vdsm.
> Actually, It will work like proxy. So we call it as consoleProxy
> now. That consoleProxy can deploy on same machine with engine,
> or standalone, or virtual machine. I think its' working flow as below:
> 1. user request open console to engine.
> 2. engine setTicket(uuid, ticket, hostofvm) to consoleProxy.
>     consoleProxy need provide api to engine.
> 3. engine return ticket to user.
> 4. user 'ssh UUID@consoleProxy' with ticket.
> 5. consoleProxy connect 'virsh -c qemu+tls://hostofvm/system console'.
>    the host of running consoleProxy should have certificates of all
> vdsm host.
> 6. consoleProxy redirect output of 'virsh -c
> qemu+tls://hostofvm/system console' with ssh protocol.
>    Same with currently implement. we can use system sshd or paramiko.
>    If we use paramiko, it almost reuse the code of consoleServer
> that I have already writen.
> After vm migrated:
> 1. engine tell consoleProxy that vm was migrated.
>     I guess engine can know vm finished migration?
>     And engine how to push the event of vm finished migration to
> consoleProxy? Engine only have rest api didn't support event push?
> Is streaming api can resolve this problem?
> 2. consoleProxy kill 'virsh console'.
> 3. reconnect to new host of vm with 'virsh console' again.
>     There will missing some character if the reconnection isn't
> enough fast.
>     This is hardly to resolve except implement ssh in qemu. I guess
> streaming api have some problem too.
> 4. continue redirect 'virsh console'.
> Actually if we implement consoleProxy out of vdsm, we don't need
> decide it will run on physical machine or
> virtual machine now.
> A lot detail need to think. I'm not cover all problem. And I haven't
> code to prove that work now. Just depend on thinking.
> Is this make sense?

How is this handled with current displays like VNC and Spice?
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