[Spice-devel] [vdsm] [RFC]about the implement of text-based console

[David Jaša]

David Jaša píše v Út 16. 10. 2012 v 00:18 +0200:
> Ewoud Kohl van Wijngaarden píše v Po 15. 10. 2012 v 22:46 +0200:
> > 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 at 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?
> 
> Extending spice to provide just serial console remoting actually seems
> the easiest way to provide remote text-only console because most of the
> code path is already mature (used for client to guest agent
> communication) and e.g. spicy

extending e.g. spicy

>  to just provide a device where e.g. screen
> could connect or just provide the console itself.
> 
> CCing spice-devel
> 
> David
> 
> > _______________________________________________
> > vdsm-devel mailing list
> > vdsm-devel at lists.fedorahosted.org
> > https://lists.fedorahosted.org/mailman/listinfo/vdsm-devel
> 

-- 

David Jaša, RHCE

SPICE QE based in Brno
GPG Key:     22C33E24 
Fingerprint: 513A 060B D1B4 2A72 7F0D 0278 B125 CD00 22C3 3E24