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Correct spelling errors in .rst files flagged by codespell. Also correct some minor grammar errors in nearby documentation. Signed-off-by: Simon Horman <horms@ovn.org> Acked-by: Mike Pattrick <mkp@redhat.com> Acked-by: Eelco Chaudron <echaudro@redhat.com>
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174 lines
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..
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Licensed under the Apache License, Version 2.0 (the "License"); you may
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not use this file except in compliance with the License. You may obtain
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a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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License for the specific language governing permissions and limitations
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under the License.
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Convention for heading levels in Open vSwitch documentation:
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======= Heading 0 (reserved for the title in a document)
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------- Heading 1
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~~~~~~~ Heading 2
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+++++++ Heading 3
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''''''' Heading 4
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Avoid deeper levels because they do not render well.
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=================================
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Monitoring VM Traffic Using sFlow
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=================================
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This document describes how to use Open vSwitch is to monitor traffic sent
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between two VMs on the same host using an sFlow collector.
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VLANs.
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.. image:: sflow.png
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:align: center
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Setup
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-----
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This guide assumes the environment is configured as described below.
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Two Physical Networks
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~~~~~~~~~~~~~~~~~~~~~
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- Data Network
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Ethernet network for VM data traffic. For experimentation, this physical
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network is optional. You can instead connect all VMs to a bridge that is not
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connected to a physical interface.
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- Management Network
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This network must exist, as it is used to send sFlow data from the agent to
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the remote collector.
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Two Physical Hosts
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~~~~~~~~~~~~~~~~~~
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The environment assumes the use of two hosts: `host1` and `hostMon`. `host` is
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a hypervisor that run Open vSwitch and has two NICs:
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- eth0 is connected to the Data Network. No IP address can be assigned on eth0
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because it is part of an OVS bridge.
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- eth1 is connected to the Management Network. eth1 has an IP address for
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management traffic, including sFlow.
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`hostMon` can be any computer that can run the sFlow collector. For this
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cookbook entry, we use `sFlowTrend
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<http://www.inmon.com/products/sFlowTrend.php>`__, a free sFlow collector that
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is a simple cross-platform Java download. Other sFlow collectors should work
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equally well. `hostMon` has a single NIC, `eth0`, that is connected to the
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Management Network. `eth0` has an IP address that can reach `eth1` on `host1`.
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Two Virtual Machines
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~~~~~~~~~~~~~~~~~~~~
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This guide uses two virtual machines - `vm1` and `vm2`- running on `host1`.
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.. note::
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VM interfaces may appear as Linux devices with names like ``vnet0``,
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``vnet1``, etc.
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Configuration Steps
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-------------------
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On `host1`, define the following configuration values in your shell
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environment::
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COLLECTOR_IP=10.0.0.1
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COLLECTOR_PORT=6343
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AGENT_IP=eth1
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HEADER_BYTES=128
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SAMPLING_N=64
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POLLING_SECS=10
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Port 6343 (``COLLECTOR_PORT``) is the default port number for sFlowTrend. If
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you are using an sFlow collector other than sFlowTrend, set this value to the
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appropriate port for your particular collector. Set your own IP address for the
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collector in the place of 10.0.0.1 (``COLLECTOR_IP``). Setting the ``AGENT_IP``
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value to eth1 indicates that the sFlow agent should send traffic from `eth1`'s
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IP address. The other values indicate settings regarding the frequency and type
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of packet sampling that sFlow should perform.
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Still on `host1`, run the following command to create an sFlow configuration
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and attach it to bridge br0::
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$ ovs-vsctl -- --id=@sflow create sflow agent=${AGENT_IP} \
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target="\"${COLLECTOR_IP}:${COLLECTOR_PORT}\"" header=${HEADER_BYTES} \
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sampling=${SAMPLING_N} polling=${POLLING_SECS} \
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-- set bridge br0 sflow=@sflow
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Make note of the UUID that is returned by this command; this value is necessary
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to remove the sFlow configuration.
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On `hostMon`, go to the `sFlowTrend
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<http://www.inmon.com/products/sFlowTrend.php>`__ and click "Install" in the
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upper right-hand corner. If you have Java installed, this will download and
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start the sFlowTrend application. Once sFlowTrend is running, the light in the
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lower right-hand corner of the sFlowTrend application should blink green to
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indicate that the collector is receiving traffic.
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The sFlow configuration is now complete, and sFlowTrend on `hostMon` should be
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receiving sFlow data from OVS on `host1`.
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To configure sFlow on additional bridges, just replace ``br0`` in the above
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command with a different bridge name.
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To remove sFlow configuration from a bridge (in this case, ``br0``), run this
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command, where "sFlow UUID" is the UUID returned by the command used to set the
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sFlow configuration initially::
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$ ovs-vsctl remove bridge br0 sflow <sFlow UUID>
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To see all current sets of sFlow configuration parameters, run::
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$ ovs-vsctl list sflow
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Troubleshooting
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---------------
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If sFlow data isn't being collected and displayed by sFlowTrend, check the
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following items:
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- Make sure the VMs are sending/receiving network traffic over bridge br0,
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preferably to multiple other hosts and using a variety of protocols.
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- To confirm that the agent is sending traffic, check that running the
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following command shows that the agent on the physical server is sending
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traffic to the collector IP address (change the port below to match the port
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your collector is using)::
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$ tcpdump -ni eth1 udp port 6343
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If no traffic is being sent, there is a problem with the configuration of OVS.
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If traffic is being sent but nothing is visible in the sFlowTrend user
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interface, this may indicate a configuration problem with the collector.
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Check to make sure the host running the collector (`hostMon`) does not have a
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firewall that would prevent UDP port 6343 from reaching the collector.
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Credit
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------
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This document is heavily based on content from Neil McKee at InMon:
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- `https://mail.openvswitch.org/pipermail/ovs-dev/2010-July/165245.html
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<https://mail.openvswitch.org/pipermail/ovs-dev/2010-July/165245.html>`__
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- `https://blog.sflow.com/2010/01/open-vswitch.html
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<https://blog.sflow.com/2010/01/open-vswitch.html>`__
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.. note::
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The configuration syntax is out of date, but the high-level
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descriptions are correct.
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