[ovs-discuss] OVS Multicast Issues version 2.4/2.5

Thu May 5 14:39:34 UTC 2016

Below are the steps i have taken to setup our current testing environment.
As of now this environment is up and functioning with multicast working.
There are however some oddities with multicast. Testing with omping
produces miked results while using our application works without issues. So
far I have tried four different ways of configuring the environment and the
current config  has been working the best.

I have upgraded the OVS to 2.5 and saw that it fixed a majority of the
ompoing issues but not the MCAST state table aging issue is still present.
This appears to be some type of possible bug with the IGMP snooping
implementation within the OVS.

*Server Specs:*
HP sl210 Gen8

   - 128 GB RAM
   - 2x Intel E5-2690
   - 1x Solarflare 10GB fiber
   - 1x SolarFlare 1GB copper
   - 2x 500GB RAID 1

*Installation process:*

OS/KVM Setup
CentOS 7 minimal x64

   - yum update -y
   - yum install qemu-kvm qemu-img virt-manager libvirt libvirt-python
   libvirt-client virt-install virt-viewer
   qemu-system-x86-2.0.0-1.el7.6.x86_64 epel-release net-tools xauth pciutils
   -y
   - sed -i s/SELINUX=enforcing/SELINUX=disabled/g /etc/selinux/config
   -
   - systemctl stop NetworkManager
   - yum -y erase NetworkManager
   - systemctl start libvirtd
   - systemctl enable libvirtd
   - chkconfig network on
   - echo "net.ipv4.ip_forward = 1"|sudo tee -a /etc/sysctl.d/99-kvm.conf
   - echo "net.bridge.bridge-nf-call-ip6tables = 0"|sudo tee -a
   /etc/sysctl.d/99-kvm.conf
   - echo "net.bridge.bridge-nf-call-iptables = 0"|sudo tee -a
    /etc/sysctl.d/99-kvm.conf
   - echo "net.bridge.bridge-nf-call-arptables = 0"|sudo tee -a
   /etc/sysctl.d/99-kvm.conf
   - echo "net.ipv4.conf.virbr0-nic.rp_filter = 0"|sudo tee -a
   /etc/sysctl.d/99-kvm.conf
   - echo "net.ipv4.conf.default.force_igmp_version = 2" |sudo tee -a
   /etc/sysctl.d/99-kvm.conf
   - echo "net.ipv4.conf.all.force_igmp_version = 2" |sudo tee -a
   /etc/sysctl.d/99-kvm.conf
   - sysctl -p /etc/sysctl.d/99-kvm.conf
   - modprobe 8021q

cat  << 'EOF' >/etc/sysconfig/modules/8021q.modules
!/bin/sh

    exec /sbin/modprobe 8021q >/dev/null 2>&1

EOF

   - chmod +x /etc/sysconfig/modules/8021q.modules

*OVS INSTALL*

AS ROOT

   - yum -y install wget openssl-devel gcc make python-devel openssl-devel
   kernel-devel graphviz kernel-debug-devel autoconf automake rpm-build
   redhat-rpm-config libtool
   - adduser ovs
   - su - ovs

AS OVS USER

   - mkdir -p ~/rpmbuild/SOURCES
   - wget http://openvswitch.org/releases/openvswitch-2.4.0.tar.gz
   - cp openvswitch-2.4.0.tar.gz ~/rpmbuild/SOURCES/
   - tar xfz openvswitch-2.4.0.tar.gz
   - sed 's/openvswitch-kmod, //g' openvswitch-2.4.0/rhel/openvswitch.spec
   > openvswitch-2.4.0/rhel/openvswitch_no_kmod.spec
   - rpmbuild -bb --nocheck openvswitch-2.4.0/rhel/openvswitch_no_kmod.spec
   - exit

AS ROOT

   -
   - mkdir /etc/openvswitch
   - yum localinstall
   /home/ovs/rpmbuild/RPMS/x86_64/openvswitch-2.4.0-1.x86_64.rpm -y
   - yum install policycoreutils-python -y
   - semanage fcontext -a -t openvswitch_rw_t "/etc/openvswitch(/.*)?"
   - systemctl start openvswitch.service
   - chkconfig openvswitch on
   - Verify install ovs-vsctl -V
   - init 6

*OVS SETUP*

   - ovs-vsctl add-br br0
   - ovs-vsctl add-port br0 ens1f1d1 vlan_mode=trunk
   - ovs-vsctl add-br vlan432 br0 432
   - ovs-vsctl add-br vlan436 br0 436
   - ovs-vsctl add-br vlan448 br0 448
   - ovs-vsctl add-br vlan452 br0 452
   - ovs-vsctl add-br vlan464 br0 464
   - ovs-vsctl set Bridge br0 mcast_snooping_enable=true

Since this is only setup for basic functionality testing this server is not
patched the way it would be in our PROD environment. A secondary bridge was
created on the OVS to facilitate management traffic.

   - ovs-vsctl add-br mgmt
   - ovs-vsctl add-port mgmt ovs
   -
   - cat  << 'EOF' >/etc/sysconfig/network-scripts/ifcfg-mgmt

DEVICE=mgmt
ONBOOT=yes
DEVICETYPE=ovs
TYPE=OVSIntPort
OVS_BRIDGE=mgmt
BOOTPROTO=static
IPADDR=10.206.0.31
NETMASK=255.255.252.0
GAREWAY=10.206.0.1
HOTPLUG=no
EOF

   - echo GATEWAY=10.206.0.1 >> /etc/sysconfig/network
   - ovs-vsctl add-br vlan400 mgmt 400
   - verify all interfaces are up using ifconfig

*VM CONFIG*

This is just a simple config of one of our VMs no specific VM tunnings were
made since this is simply to test basic multicast functionality. However
there is one odd config that would not be standard in a real environment.
There is a macvtap interface taped to the physical mgmt NIC on the host.
This allows for the ability to pxe install the VM and access it from
outside the network. VLANs 432 436 448 452 464 are the VLANs that multicast
traffic will pass through.

See attached:
vm-config.xml

*OVS-SWITCH *

See attached
ovs-switch.txt

*OMPING TESTS*

omping -m 239.255.1.90 10.206.50.51 10.206.48.33

*Two VMs on S1ame KVM Host. **(OVS 2.4)*
On VLAN 448 between two VMs on the KVM host connected to the same  Open
vSwitch Mmulticast flows between the VMs cleanly no Duplicate packets or
flooding into other VMs. The only issue is that the OVS does not seem to be
interpreting the IGMP reports being sent out causing the OVS to age out the
the connection on its MCAST table, but multicast traffic still continues to
flow cleanly.

*One VM on KVM to Another Server On Network. (OVS 2.4)*
On VLAN 448 between one VM on the KVM host cand another server on the same
network Multicast traffic flows but has issues. The VM on the KVM host
receives the traffic cleanly but the external server is receiving duplicate
packets. Also the OVS does not seem to be interpreting the IGMP reports
being sent out causing the OVS to age out the the connection on its MCAST
table, but this time once it ages out the duplicates stop. Running a
tcpdump on the receiving host confirms that the packets are truly
duplicates.

omping running on VM on KVM host
10.206.50.33 : joined (S,G) = (*, 239.255.1.90), pinging
10.206.50.33 :   unicast, seq=1, size=69 bytes, dist=0, time=0.466ms
10.206.50.33 :   unicast, seq=2, size=69 bytes, dist=0, time=0.582ms
10.206.50.33 : multicast, seq=2, size=69 bytes, dist=0, time=0.587ms
10.206.50.33 :   unicast, seq=3, size=69 bytes, dist=0, time=0.643ms
10.206.50.33 : multicast, seq=3, size=69 bytes, dist=0, time=0.638ms
10.206.50.33 :   unicast, seq=4, size=69 bytes, dist=0, time=0.535ms
10.206.50.33 : multicast, seq=4, size=69 bytes, dist=0, time=0.539ms
10.206.50.33 :   unicast, seq=5, size=69 bytes, dist=0, time=0.461ms
10.206.50.33 : multicast, seq=5, size=69 bytes, dist=0, time=0.536ms

omping running on server on the same network
10.206.50.51 : joined (S,G) = (*, 239.255.1.90), pinging
10.206.50.51 :   unicast, seq=1, size=69 bytes, dist=0, time=0.255ms
10.206.50.51 : multicast, seq=1, size=69 bytes, dist=0, time=0.705ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.738ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.743ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.746ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.756ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.758ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.761ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.764ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.767ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.770ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.772ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.774ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.777ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.779ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.782ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.789ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.792ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.795ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.798ms
10.206.50.51 : multicast, seq=1 (dup), size=69 bytes, dist=0, time=0.803ms

*Running Our Own Application. **(OVS 2.4 and OVS 2.5)*

Running our own application that resides in a VM on the KVM host behaves
properly. This VM communicates to other physical and virtual servers on the
network without issues. There is no duplicate packets being received by
other hosts, there is no flooding into other VMs and the OVS is
interpreting the IGMP reports being sent an updating the MCAST table
properly.
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