Archive for the ‘Virtualization’ Category

Cisco UCS : Tracing packet paths with a MAC address

March 14th, 2014 Comments off

In the UCS world where a virtual NIC on a virtual server is connected to a virtual port on a virtual switch by a virtual cable, it is not surprising that there can be confusion about what path packets are actually taking through the UCS infrastructure.

Similarly knowing the full data path through the UCS infrastructure is essential to understanding troubleshooting and testing failover.

In this post I will demonstrate how to trace the paths of the packets in a Cisco UCS Data Center.

The diagram below shows a Half width blade with a vNIC called eth0 created on a Cisco VIC (M81KR) with its primary path mapped to Fabric A. For simplicity only one IO Module to Fabric Interconnect link is shown in the diagram, as well as only one of the Host Interfaces (HIFs / Server facing ports) on the IO module.

1 overview

With the MAC address, you first need to find out the virtual circuit number with the following commands. Note that it will show nothing if you are in the wrong FI.

2 mac to veth

With the Veth#, now we can find the Chassis/Server ID with this command

3 veth to chassis-server

We can go further and find the Uplink/Border Interface where the Fabric Interconnect connects to the LAN with this command

4 veth to uplink

Next , we will find the FI port (Server port) that connect to this virtual circuit with the following command

Where Ethernet #/#/# is the “Bound Interface” you found above with the “show int veth #” command
3 veth to chassis-server

Now you should have the server port (Fabric-if), to find the
FEX Network Port
5 F-if to FEX-uplink

The steps above should help you identify the paths of the packets. For in depth network troubleshooting , see the following Cisco slide

vSphere 5.5: What’s new?

September 7th, 2013 Comments off

Thanks to VMWare Arena group, who put together this table.


Categories: Virtualization

VMWare vShield-App vs vShield-Edge

June 14th, 2013 Comments off

One of my customer called me today to ask what the difference was between vShieldApp and vShieldEdge, as they were looking at a competing firewall.

I paused for a minute because I could not explain it clearly, as Vmware’s website isn’t that clear about it either. I reached out to my trusted Vmware SME and he was able to explain the difference to me.

vShieldApp is a hypervisor based firewall (internal to cluster) – port based ACL functionality to isolate VM’s from each other.

vShieldEdge is a virtual firewall (internal cluster or to external world)

This is how VMWare explains it
(vShield-App is on the left, vShield-Edge is on the right)

Clear as mud ? This article will help explain further
VMware® vShield Edge and vShield App Reference Design Guide

What happens when the vCenter crash?

May 22nd, 2013 Comments off

Seva, a VMware Technical Account Manager, put together a cool table with the implications of a VirtualCenter crash. Click the image for the pdf file. The most important thing to remember is that the VM’s keep running whatever happens to your VC Server and HA will still work if VC fails.

Categories: Virtualization

VMWare ESXi USB Passthrough

November 29th, 2012 Comments off

1. USB pass through support was brought in with ESX 4.1, so make sure your Host machine is 4.1 or newer.
2. Also the “Hardware Version” of the virtual machine itself must be (at least) version 7.
3. Your first task is to add a “USB Controller” the the VM. (You will need to power the VM down before you can do this). Edit Settings > Hardware Tab > Add.

4. Select USB Controller from the list > Next > Next > Finish.
5. OK.
6. Start up the VM.
7. Once you have a USB controller, you can present the USB devices that are connected to the Host ESX server.
8. Add Hardware.
9. You will now see “USB device” as an option > Next.
10. Now you can see the USB devices that are connected to the Host (In this case an HP UPS) > Select your device > Next > Finish > OK.

Note: The option “Support vMotion while device is connected” option will do exactly as is suggests, if the VM is vMotioned to another Host, the USB device will remain connected to this VM. (That is very cool if you think about what it has to do to make that happen).

11. The first time you boot into the operating system, (In this case Server 2008 R2) it will detect the hardware, here I’m opening Device Manager.
12. And you can see the USB controller, it will need a reboot before it starts them with the correct drivers.
13. Post reboot, the USB controller and devices will load, and be connected successfully.

Note: After this you can simply add and remove USB devices, without the need for any downtime.
14. Now in Device Manager everything looks a lot healthier.

A more detail article from VMWare can also be seen here:

Categories: Virtualization