Open vSwitch Networks¶
This guide describes how to use the Open vSwitch network drivers. They provide network isolation using VLANs by tagging ports and basic network filtering using OpenFlow. Other traffic attributes that may be configured through Open vSwitch are not modified.
The VLAN ID will be the same for every interface in a given network, calculated automatically by OpenNebula. It may also be forced by specifying an VLAN_ID
parameter in the Virtual Network template.
Warning
This driver doesn’t support Security Groups.
OpenNebula Configuration¶
The VLAN ID is calculated according to this configuration option /etc/one/oned.conf:
# VLAN_IDS: VLAN ID pool for the automatic VLAN_ID assigment. This pool
# is for 802.1Q networks (Open vSwitch and 802.1Q drivers). The driver
# will try first to allocate VLAN_IDS[START] + VNET_ID
# start: First VLAN_ID to use
# reserved: Comma separated list of VLAN_IDs or ranges. Two numbers
# separated by a colon indicate a range.
VLAN_IDS = [
START = "2",
RESERVED = "0, 1, 4095"
]
By modifying this section, you can reserve some VLANs so they aren’t assigned to a Virtual Network. You can also define the first VLAN ID. When a new isolated network is created, OpenNebula will find a free VLAN ID from the VLAN pool. This pool is global and it’s also shared with the 802.1Q Networks.
The following configuration parameters can be adjusted in /var/lib/one/remotes/etc/vnm/OpenNebulaNetwork.conf
:
Parameter |
Description |
---|---|
|
Set to |
|
Set to |
|
(Hash) Options for Open vSwitch bridge creation |
Note
Remember to run onehost sync -f
to synchronize the changes to all the nodes.
Defining Open vSwitch Network¶
To create an Open vSwitch network, include the following information:
Attribute |
Value |
Mandatory |
---|---|---|
|
Set |
YES |
|
Name of the physical network device that will be attached to the bridge |
NO (unless using VLANs) |
|
Name of the Open vSwitch bridge to use |
NO |
|
The VLAN ID, will be generated if not defined and |
NO |
|
Ignored if |
NO |
|
The MTU for the Open vSwitch port |
NO |
For example, you can define an Open vSwitch Network with the following template:
NAME = "private4"
VN_MAD = "ovswitch"
BRIDGE = vbr1
VLAN_ID = 50 # Optional
...
Warning
Currently, if IP Spoofing enabled, only one NIC per VM for the same Open vSwith network can be attached.
Multiple VLANs (VLAN trunking)¶
VLAN trunking is also supported by adding the following tag to the NIC
element in the VM template or to the virtual network template:
VLAN_TAGGED_ID
: Specify a range of VLANs to tag, for example:1,10,30,32,100-200
.
Using Open vSwitch on VXLAN Networks¶
This section describes how to use Open vSwitch on VXLAN networks. To use VXLAN you need to use a specialized version of the Open vSwitch driver that incorporates the features of the VXLAN driver. It’s necessary to be familiar with these two drivers, their configuration options, benefits, and drawbacks.
The VXLAN overlay network is used as a base with the Open vSwitch (instead of regular Linux bridge) on top. Traffic on the lowest level is isolated by the VXLAN encapsulation protocol and Open vSwitch still allows second level isolation by 802.1Q VLAN tags inside the encapsulated traffic. The main isolation is always provided by VXLAN, not 802.1Q VLANs. If 802.1Q is required to isolate the VXLAN, the driver needs to be configured with user-created 802.1Q tagged physical interface.
This hierarchy is important to understand.
OpenNebula Configuration¶
There is no configuration specific to this driver, except the options specified above and in the VXLAN Networks guide.
Defining an Open vSwitch - VXLAN Network¶
To create a network, include the following information:
Attribute |
Value |
Mandatory |
---|---|---|
|
Set |
YES |
|
Name of the physical network device that will be attached to the bridge. |
YES |
|
Name of the Open vSwitch bridge to use |
NO |
|
The outer VXLAN network ID. |
YES (unless |
|
If |
YES (unless |
|
The inner 802.1Q VLAN ID. If this attribute is not defined a VLAN ID will be generated if AUTOMATIC_VLAN_ID is set to YES. |
NO |
|
Ignored if |
NO |
|
The MTU for the VXLAN interface and bridge |
NO |
For example, you can define an Open vSwitch - VXLAN Network with the following template:
NAME = "private5"
VN_MAD = "ovswitch_vxlan"
PHYDEV = eth0
BRIDGE = ovsvxbr0.10000
OUTER_VLAN_ID = 10000 # VXLAN VNI
VLAN_ID = 50 # Optional VLAN ID
...
In this example, the driver will check for the existence of bridge ovsvxbr0.10000
. If it doesn’t exist, it will be created. Also, the VXLAN interface eth0.10000
will be created and attached to the Open vSwitch bridge ovsvxbr0.10000
. When a virtual machine is instantiated, its bridge ports will be tagged with 802.1Q VLAN ID 50
.
Open vSwitch with DPDK¶
Warning
This section is only relevant for KVM guests.
This section describes how to use a DPDK datapath with the Open vSwitch drivers. When using the DPDK backend, the OpenNebula drivers will automatically configure the bridges and ports accordingly.
Please consider the following when using the DPDK datapath for Open vSwitch:
An Open vSwitch version compiled with DPDK support is required.
The VMs need to use the virtio interface for its NICs.
Hugepages needs to be configured in the Hosts
VMs needs to use be configured to use NUMA pinning and hugepages. See here.
Host Configuration¶
Note
This section will use an Ubuntu22.04 server to show working configurations. You may need to adapt them to other Linux distributions.
Setup Hugepages and iommu¶
Hugepages are virtual memory pages of a size greater than the 4K default. Increasing the size of the page reduces the number of pages in the system and hence the entries needed in the TLB to perform virtual address translations.
The size of virtual pages supported by the system can be check from the CPU flags:
pse
for 2Mpdpe1g
for 1G
For 64-bit applications it is recommended to use 1G. Note that on NUMA systems, the pages reserved are divided equally between sockets.
For example to configure default page size of 1G and 250 hugepages at boot time:
# vim /etc/default/grub
...
GRUB_CMDLINE_LINUX_DEFAULT="intel_iommu=on default_hugepagesz=1G hugepagesz=1G hugepages=250"
# update-grub
After rebooting the system mount the hugepage folder so application can access them:
# mkdir /mnt/hugepages1G
# vim /etc/fstab
...
nodev /mnt/hugepages1G hugetlbfs pagesize=1GB 0 0
# mount /mnt/hugepages1G
Now check hugepages are allocated to NUMA nodes, for example (or with numastat -m
):
# mkdir /mnt/hugepages1G# cat /sys/devices/system/node/node*/meminfo | grep -i '\<huge'
Node 0 HugePages_Total: 125
Node 0 HugePages_Free: 125
Node 0 HugePages_Surp: 0
Node 1 HugePages_Total: 125
Node 1 HugePages_Free: 125
Node 1 HugePages_Surp: 0
And finally iommu should be also enabled:
# grep -i dmar dmesg
[ 0.010651] kernel: ACPI: DMAR 0x000000007BAFE000 0000F0 (v01 DELL PE_SC3 00000001 DELL 00000001)
[ 0.010695] kernel: ACPI: Reserving DMAR table memory at [mem 0x7bafe000-0x7bafe0ef]
[ 1.837579] kernel: DMAR: IOMMU enabled
Install OVS with DPDK support¶
We just need to install the dpdk version of the package and update alternatives accordingly:
# apt install openvswitch-switch-dpdk
# update-alternatives --set ovs-vswitchd /usr/lib/openvswitch-switch-dpdk/ovs-vswitchd-dpdk
Now, restart openvswitch service and check dpdk is enabled:
# systemctl restart openvswitch-switch.service
# grep DPDK openvswitch/ovs-vswitchd.log
2022-11-24T12:30:24.500Z|00041|dpdk|ERR|DPDK not supported in this copy of Open vSwitch.
2022-11-24T12:33:02.905Z|00007|dpdk|INFO|Using DPDK 21.11.2
2022-11-24T12:33:02.905Z|00008|dpdk|INFO|DPDK Enabled - initializing...
2022-11-24T12:33:02.905Z|00012|dpdk|INFO|Per port memory for DPDK devices disabled.
2022-11-24T12:33:02.914Z|00016|dpdk|INFO|EAL: Detected shared linkage of DPDK
2022-11-24T12:33:04.303Z|00032|dpdk|INFO|DPDK Enabled - initialized
# ovs-vsctl get Open_vSwitch . dpdk_initialized
true
Configure Open vSwitch¶
Next step is to tune the execution parameters of the polling mode drivers (PMD) threads by pinning them into specific CPUs and assigning some hugepages.
To specify the CPU cores we need to set a binary mask, where each bit represents a CPU core by its ID. For example 0xF0
is 11110000
, bits 4,5,6,7 are set to 1 so CPU cores 4,5,6,7 would be use for PMDs. Usually, it is recommended to allocate same number of cores across NUMA nodes.
For example to set cores 0,28,1,29 and 2G of hugepages per NUMA node, execute the following commands:
# ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=0x30000003
# ovs-vsctl set Open_vSwitch . other_config:dpdk-socket-mem="2048,2048"
# ovs-vsctl set Open_vSwitch . other_config:dpdk-hugepage-dir="/mnt/hugepages1G"
# systemctl restart openvswitch-switch.service
Configure Open vSwitch Bridge¶
OpenNebula does not support adding and configuring DPDK physical devices. Binding cards to vfio-pci driver needs to be configured before using the DPDK network in OpenNebula. Usually, Open vSwitch setups only requires one bridge so these steps can be easily automated during the host installation.
In this example, we’ll be creating a bond with to cards (each one attached to a different NUMA node). Let’s first trace the cards with the dpdk-debind.py
tool, and then bind the cards to the vfio-pci driver.
# dpdk-devbind.py --status
...
Network devices using kernel driver
===================================
0000:01:00.1 'Ethernet Controller X710 for 10GbE SFP+ 1572' if=eno2 drv=i40e unused=vfio-pci
0000:83:00.1 'Ethernet Controller X710 for 10GbE SFP+ 1572' if=enp131s0f1 drv=i40e unused=vfio-pci
# dpdk-devbind.py --bind=vfio-pci enp131s0f1
# dpdk-devbind.py --bind=vfio-pci eno2
# dpdk-devbind.py --status
...
Network devices using DPDK-compatible driver
============================================
0000:01:00.1 'Ethernet Controller X710 for 10GbE SFP+ 1572' drv=vfio-pci unused=i40e
0000:83:00.1 'Ethernet Controller X710 for 10GbE SFP+ 1572' drv=vfio-pci unused=i40e
Now we can add the cards to an Open vSwitch port, or in this example create a bond port with both:
# ovs-vsctl add-br onebr.dpdk -- set bridge onebr.dpdk datapath_type=netdev
# ovs-vsctl add-bond onebr.dpdk bond1 x710_1 x710_83 \
-- set Interface x710_1 type=dpdk options:dpdk-devargs=0000:01:00.1 \
-- set Interface x710_83 type=dpdk options:dpdk-devargs=0000:83:00.1
# ovs-vsctl show
Bridge onebr.dpdk
datapath_type: netdev
Port onebr.dpdk
Interface onebr.dpdk
type: internal
Port bond1
Interface x710_83
type: dpdk
options: {dpdk-devargs="0000:83:00.1"}
Interface x710_1
type: dpdk
options: {dpdk-devargs="0000:01:00.1"}
ovs_version: "2.17.2"
We are all set now, the bridge onebr.dpdk
is ready to be used by OpenNebula.
OpenNebula Configuration¶
There are no special configuration on the OpenNebula server. Note that the sockets used by the vhost interface are created in the VM directory (/var/lib/one/datastores/<ds_id>/<vm_id>
) and named after the switch port.
Using DPDK in your Virtual Networks¶
There are no additional changes, simply:
Create your networks using the
ovswitch
driver, see above.Change configuration of the
BRIDGE_TYPE
of the network toopenvswitch_dpdk
using either the CLI commandonevnet update
or Sunstone.
An example of a Virtual Network template for the previous configuration could be:
NAME = "DPDK_VSBC_HA2"
BRIDGE = "onebr.dpdk"
BRIDGE_TYPE = "openvswitch_dpdk"
SECURITY_GROUPS = "0"
VLAN_ID = "1402"
VN_MAD = "ovswitch"
# note there is no PHYDEV, after creation it will show PHYDEV = ""
Using DPDK in your Virtual Machines¶
The following settings needs to be enabled:
Make sure that the NIC model is set to
virtio
. This setting can be added as a default in/etc/one/vmm_exec/vmm_exec_kvm.conf
.In order to use the vhost-user interface in libvirt hugepages needs to be enabled. OVS reads/write network packages from/to the memory (hugepages) of the guest. The memory access mode MUST be shared, and the VM MUST configure huge pages.
An example of a Virtual Machine template for the previous configuration could be:
NAME = "DPDK_VM"
MEMORY = "4096"
NIC = [ NETWORK = "DPDK_VSBC_HA2" ]
TOPOLOGY = [
CORES = "2",
HUGEPAGE_SIZE = "1024",
MEMORY_ACCESS = "shared",
PIN_POLICY = "THREAD",
SOCKETS = "1",
THREADS = "2"
]
You can verify that the VMs are using the vhost interface by looking at their domain definition in the Host. You should see something like:
<domain type='kvm' id='417'>
<name>one-10</name>
...
<devices>
...
<interface type='vhostuser'>
<mac address='02:00:c0:a8:7a:02'/>
<source type='unix' path='/var/lib/one//datastores/0/10/one-10-0' mode='server'/>
<target dev=''/>
<model type='virtio'/>
<alias name='net0'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
</interface>
...
</domain>
And the associated port in the bridge using the qemu vhost interface:
Bridge onebr.dpdk
datapath_type: netdev
Port "one-10-0"
tag: 1420
Interface "one-10-0"
type: dpdkvhostuserclient
options: {vhost-server-path="/var/lib/one//datastores/0/10/one-10-0"}
...
Using Open vSwitch with Q-in-Q¶
Q-in-Q is an amendment to the IEEE 802.1Q specification that provides the capability for multiple VLAN tags to be inserted into a single Ethernet frame. Using Q-in-Q (aka C-VLAN, customer VLAN) tunneling allows to create Layer 2 Ethernet connection between customers cloud infrastructure and OpenNebula VMs, or use a single service VLAN to bundle different customer VLANs.
OpenNebula Configuration¶
There is no configuration specific for this use case, just consider the general options specified above.
Defining a Q-in-Q Open vSwitch Network¶
To create a network you need to include the following information:
Attribute |
Value |
Mandatory |
---|---|---|
|
Set |
YES |
|
Name of the physical network device that will be attached to the bridge. |
YES |
|
Name of the Open vSwitch bridge to use |
NO |
|
The service 802.1Q VLAN ID. If not defined the VLAN ID tag will be generated if AUTOMATIC_VLAN_ID is set to YES. |
NO |
|
Ignored if |
NO |
|
Customer VLAN IDs, as a comma separated list (ranges supported) |
YES |
|
Tag Protocol Identifier (TPID) for the service VLAN tag. Use |
NO |
|
The MTU for the Open vSwitch port |
NO |
For example, you can define an Open vSwitch - QinQ Network with the following template:
NAME = "qinq_net"
VN_MAD = "ovswitch"
PHYDEV = eth0
VLAN_ID = 50 # Service VLAN ID
CVLANS = "101,103,110-113" # Customer VLAN ID list
In this example, the driver will assign and create an Open vSwitch bridge and will attach the interface eth0
it. When a virtual machine is instantiated, its bridge ports will be tagged with 802.1Q VLAN ID 50
and service VLAN IDs 101,103,110,111,112,113
. The configuration of the port should be similar to the that of following example that shows the second (NIC_ID=1
) interface port one-1-5
for VM 5:
# ovs-vsctl list Port one-5-1
_uuid : 791b84a9-2705-4cf9-94b4-43b39b98fe62
bond_active_slave : []
bond_downdelay : 0
bond_fake_iface : false
bond_mode : []
bond_updelay : 0
cvlans : [101, 103, 110, 111, 112, 113]
external_ids : {}
fake_bridge : false
interfaces : [6da7ff07-51ec-40e9-97cd-c74a36e2c267]
lacp : []
mac : []
name : one-5-1
other_config : {qinq-ethtype="802.1q"}
protected : false
qos : []
rstp_statistics : {}
rstp_status : {}
statistics : {}
status : {}
tag : 100
trunks : []
vlan_mode : dot1q-tunnel