Prerequisites for installing a Citrix ADC VPX instance on Linux-KVM platform
Check the minimum system requirements for a Linux-KVM server running on a Citrix ADC VPX instance.
CPU requirement:
- 64-bit x86 processors with the hardware virtualization feature included in Intel VT-X processors.
To test whether your CPU supports the Linux host, enter the following command at the host Linux shell prompt:
*.egrep '^flags.*(vmx|svm)' /proc/cpuinfo*
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If the BIOS settings for the preceding extension are disabled, you must enable them in the BIOS.
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Provide at least 2 CPU cores to Host Linux.
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There is no specific recommendation for processor speed, but higher the speed, the better the performance of the VM application.
Memory (RAM) requirement:
Minimum 4 GB for the host Linux kernel. Add more memory as required by the VMs.
Hard disk requirement:
Calculate the space for Host Linux kernel and VM requirements. A single Citrix ADC VPX VM requires 20 GB of disk space.
Software requirements
The Host kernel used must be a 64-bit Linux kernel, release 2.6.20 or later, with all virtualization tools. Citrix recommends newer kernels, such as 3.6.11-4 and later.
Many Linux distributions such as Red Hat, CentOS, and Fedora, have tested kernel versions and associated virtualization tools.
Guest VM hardware requirements
Citrix ADC VPX supports IDE and virtIO hard disk type. The Hard Disk Type has been configured in the XML file, which is a part of the Citrix ADC package.
Networking requirements
Citrix ADC VPX supports virtIO para-virtualized, SR-IOV, and PCI Passthrough network interfaces.
For more information about the supported network interfaces, see:
- Provision the Citrix ADC VPX instance by using the Virtual Machine Manager
- Configure a Citrix ADC VPX instance to use SR-IOV network interfaces
- Configure a Citrix ADC VPX instance to use PCI passthrough network interfaces
Source Interface and Modes
The source device type can be either Bridge or MacVTap. In MacVTap, four modes are possible - VEPA, Bridge, Private, and Pass-through. Check the types of interfaces that you can use and the supported traffic types, as per the following:
Bridge:
- Linux Bridge.
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Ebtablesandiptablessettings on host Linux might filter the traffic on the bridge if you do not choose the correct setting or disableIPtableservices.
MacVTap (VEPA mode):
- Better performance than a bridge.
- Interfaces from the same lower device can be shared across the VMs.
- Inter-VM communication using the same
- lower device is possible only if the upstream or downstream switch supports VEPA mode.
MacVTap (private mode):
- Better performance than a bridge.
- Interfaces from the same lower device can be shared across the VMs.
- Inter-VM communication using the same lower device is not possible.
MacVTap (bridge mode):
- Better as compared to bridge.
- Interfaces out of the same lower device can be shared across the VMs.
- Inter-VM communication using the same lower device is possible, if the lower device link is UP.
MacVTap (Pass-through mode):
- Better as compared to bridge.
- Interfaces out of the same lower device cannot be shared across the VMs.
- Only one VM can use the lower device.
Note:
For best performance by the VPX instance, ensure that the
groandlrocapabilities are switched off on the source interfaces.
Properties of source interfaces
Make sure that you switch off the generic-receive-offload (gro) and large-receive-offload (lro) capabilities of the source interfaces. To switch off the gro and lro capabilities, run the following commands at the host Linux shell prompt.
ethtool -K eth6 gro off
ethool -K eth6 lro off
Example:
[root@localhost ~]# ethtool -K eth6
Offload parameters for eth6:
rx-checksumming: on
tx-checksumming: on
scatter-gather: on
tcp-segmentation-offload: on
udp-fragmentation-offload: off
generic-segmentation-offload: on
generic-receive-offload: off
large-receive-offload: off
rx-vlan-offload: on
tx-vlan-offload: on
ntuple-filters: off
receive-hashing: on
[root@localhost ~]#
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Example:
If the host Linux bridge is used as a source device, as in the following example, and lro capabilities must be switched off on the VNet interfaces, which are the virtual interfaces connecting the host to the guest VMs.
[root@localhost ~]# brctl show eth6_br
bridge name bridge id STP enabled interfaces
eth6_br 8000.00e0ed1861ae no eth6
vnet0
vnet2
[root@localhost ~]#
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In the preceding example, the two virtual interfaces are derived from the eth6_br and are represented as vnet0 and vnet2. Run the following commands to switch off gro and lro capabilities on these interfaces.
ethtool -K vnet0 gro off
ethtool -K vnet2 gro off
ethtool -K vnet0 lro off
ethtool -K vnet2 lro off
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Promiscuous mode
The promiscuous mode must be enabled for the following features to work:
- L2 mode
- Multicast traffic processing
- Broadcast
- IPV6 traffic
- virtual MAC
- Dynamic routing
Use the following command to enable the promiscuous mode.
[root@localhost ~]# ifconfig eth6 promisc
[root@localhost ~]# ifconfig eth6
eth6 Link encap:Ethernet HWaddr 78:2b:cb:51:54:a3
inet6 addr: fe80::7a2b:cbff:fe51:54a3/64 Scope:Link
UP BROADCAST RUNNING PROMISC MULTICAST MTU:9000 Metric:1
RX packets:142961 errors:0 dropped:0 overruns:0 frame:0
TX packets:2895843 errors:0 dropped:0 overruns:0 carrier:0
collisions:0 txqueuelen:1000
RX bytes:14330008 (14.3 MB) TX bytes:1019416071 (1.0 GB)
[root@localhost ~]#
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Module required
For better network performance, make sure the vhost_net module is present in the Linux host. To check the existence of vhost_net module, run the following command on the Linux host:
lsmod | grep "vhost\_net"
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If vhost_net is not yet running, enter the following command to run it:
modprobe vhost\_net
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