[ovs-discuss] Sflow packet samples in Openstack environment on OVS bridge

[harsh jain]

Hi Peter,

Thanks for reply.

What is the difference in vSwitch configuration in Openstack environment
 and in standalone use. if i try to enable sflow on OVS-bridge having
following setup. It captures packet in both direction. I think I am not
able to understand exactly what ingress means.

In PC
eth0--> br0-->tap0 (mktun command) --> Passed the tap device to qemu to
launch VM.

In compute node
VM-->tap-->Linux Bridge --veth pair-->br-int(sflow enabled)-veth
pair->br-tun


Actually We can not use br-ex to enable flow because sflow sample contain
GRE header.


Thanks & Regards
Harsh Jain



On Wed, Apr 22, 2015 at 8:00 PM, Peter Phaal <peter.phaal at inmon.com> wrote:

> The sFlow implementation in OVS applies ingress sampling. To get full
> coverage into all traffic paths you need to enable sFlow on all bridges.
> For OpenStack, enabling sFlow on br-ex should give you visibility into the
> traffic destined to VMs.
>
> You may also want to take a look at the Host sFlow agent (
> http://host-sflow.sourceforge.net/). It can automatically manage the OVS
> sFlow settings and will also export hypervisor and VM CPU, memory, disk and
> network IO stats.
>
> On Apr 22, 2015, at 12:46 AM, harsh jain <harshjain32 at gmail.com> wrote:
>
> Hi,
>
> I tried to collect sflow packet on OVS switch in Openstack. But captured
> paackets contain only traffic coming out from the VM i.e samples contain
> Raw Packet of VM to external network direction only.following command is
> used to enable
>
> export COLLECTOR_IP=10.3.5.112
> export COLLECTOR_PORT=6343
> export AGENT_IP=eth1
> export HEADER_BYTES=256
> export SAMPLING_N=1
> export POLLING_SECS=10
>
> ovs-vsctl -- --id=@sflow create sflow agent=${AGENT_IP}
> target=\"${COLLECTOR_IP}:${COLLECTOR_PORT}\" header=${HEADER_BYTES}
> sampling=${SAMPLING_N} polling=${POLLING_SECS} -- set bridge br-int
> sflow=@sflow
>
> Connection is
> VM ->tap device->br-int(sflow enabled)-----veth-pair----->br-data-eth.
>
> Why packets are colected for 1 direction only?
>
>
> Thanks & Regards
> Harsh Jain
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