Re: [libvirt] [PATCH v2] network: make openvswitch call timeout compile time configurable
On 01/25/2017 04:16 AM, Laine Stump wrote:
On 01/24/2017 10:53 AM, Boris Fiuczynski wrote:
> Since a successful completion of the calls to openvswitch is expected
> a long timeout should be chosen to account for heavily loaded systems.
> Therefore this patch increases the timeout value from 5 to 120 seconds
> as default value and also allows to set the openvswitch timeout value
> by specifying with-ovs-timeout when running configure.
Why make it configurable during build? I don't think we do this with any
other type of timeout value or limit. If you think it may need to change
based on circumstances, why not just put it in libvirtd.conf and be done
with it?
In the meantime, I agree with Michal that any machine that takes 120
seconds to get a response from any ovs command is beyond the limits of
usable; we certainly shouldn't cater our defaults to that.
The first version of the patch was send in November last year hard
coding the default value which resulted in this response.
https://www.redhat.com/archives/libvir-list/2016-November/msg01063.html
That is why I created the current proposal. Certainly allowing the ovs
timeout to be specified in libvirtd.conf allows much more flexibility
than the current patch provides.
The system we saw ovs timeout problems on had 128 cpus with a load avg
of 74 and the system shows 41% idle. I would not call that an
unreasonable load level on a system and I also would not expect getting
errors like:
error: Disconnected from qemu:///system due to keepalive timeout
error: Failed to start domain zs93k1g80002
error: internal error: connection closed due to keepalive timeout
when trying to start a domain which are caused by ovs command timing
out. Please notice that the virsh start command itself, for the domain,
did exceed the keepalive time limit.
In addition a later retry with the same amount of load on the system
succeeded with starting the domain instead of running into the previous
error again caused by the ovs timeout when an ovs port is created.
--
Mit freundlichen Grüßen/Kind regards
Boris Fiuczynski
IBM Deutschland Research & Development GmbH
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