On Tue, Oct 01, 2013 at 06:13:10PM +0200, Viktor Mihajlovski wrote:
On 10/01/2013 03:02 PM, Daniel P. Berrange wrote:
On Mon, Sep 30, 2013 at 04:24:49PM +0100, Daniel P. Berrange wrote:
On Mon, Sep 30, 2013 at 05:23:33PM +0200, Michal Privoznik wrote:
On 30.09.2013 17:02, Claudio Bley wrote:
Hi.
When trying to do a screenshot of a remote domain connected via qemu+tcp (for testing purposes only), I receive this error:
---------------------------------------------------------------------- virsh -c qemu+tcp://dev/system Welcome to virsh, the virtualization interactive terminal.
Type: 'help' for help with commands 'quit' to quit
virsh # version Compiled against library: libvir 0.9.8 Using library: libvir 0.9.8 Using API: QEMU 0.9.8 Running hypervisor: QEMU 1.5.1
virsh # screenshot 2 /tmp/screendump error: could not receive data from domain 2 error: packet 1048600 bytes received from server too large, want 262144
virsh # 2013-09-30 14:47:05.158+0000: 21646: info : libvirt version: 0.9.8 2013-09-30 14:47:05.158+0000: 21646: warning : virNetClientIncomingEvent:1660 : Something went wrong during async message processing ----------------------------------------------------------------------
I'm using Ubuntu LTS 12.04.3, latest version in the repo which is 0.9.8-2ubuntu17.13.
This works as expected. 0.9.8 still had a small buffer for RPC messages. It's since 0.9.13 release that we've switched to dynamically allocated buffer and hence could size up the limit for incoming data. Update the client and problem will just go away.
Actually that is not working as expected. The old client should *always* be able to talk to a new server. If the new server is unconditionally sending back data that is too large for the client, this is a bug.
This problem was fixed in
commit 27e81517a876dcb738dd8a9bb2e0e68d71c3b7e3 Author: Daniel P. Berrange <berrange@redhat.com> Date: Mon Sep 30 17:27:51 2013 +0100
Fix max stream packet size for old clients
The libvirtd server pushes data out to clients. It does not know what protocol version the client might have, so must be conservative and use the old payload limits. ie send no more than 256kb of data per packet.
And backported to stable branches.
Daniel
I tried libvirt 1.1.3 containing the commit on the server and Ubuntu libvirt 0.9.8 as the client and still have the issue if the message is greater than 256KB. The problem is that the old client checks the message size during decode (which is greater than the client's max message size).
Not sure how to get out of this ...
What were you doing to get a message greater than 256KB ? This patch did not attempt to fix all possible combinations. If a API call such as virConnectListAllDomains has so much data that it requires > 256KB to encode, this fix won't solve that. There is nothing we can do for API calls which have a genuine need to exceed the old size limit. I was only addressing the case of virStreamPtr data which was mistakenly hardcoded in the server to try sending 16 MB of data at once. I switched it to only try to send 256 KB of data per stream packet. Daniel -- |: http://berrange.com -o- http://www.flickr.com/photos/dberrange/ :| |: http://libvirt.org -o- http://virt-manager.org :| |: http://autobuild.org -o- http://search.cpan.org/~danberr/ :| |: http://entangle-photo.org -o- http://live.gnome.org/gtk-vnc :|