Friday, May 31, 2013

Disabling Hot Add/Remove on VMware vSphere


It has been a long time since VMware introduced the capability of Hot Add/Remove devices, like CPU and Memory, along with them we could also Hot Add/Remove network cards and SCSI controllers.

It was a huge improvement and helped a lot of System Administrators to reduce the server’s downtime when some upgrade was required, (keep in mind that the Operational System must be able to recognized the change that was made on its resources and adjusts itself accordingly.

But, with VMware Horizon View, we saw a proliferation of VDI projects, and this amazing feature also allows end users, with certain privileges, to remove the NIC of their own systems, intentionally or not, causing and immediate disconnection and a break of the VDI service. 
You probably noted an increase of calls into support.

It’s so easy to remove the NIC by accident that could happen even with the most Senior Technical guy.

The NIC is just there between your USB devices and stuff.



 
Don’t worry about removing the SCSI adapters, since it’s probably in use by the O.S., so it will not allow the removal of it.



Yeah, I know, on the support side you will need to prove the NIC was removed by someone and there's no problem on the environment,

You can get the prove you need at the Virtual Machine's log file, look for the following entry:

Mar 21 03:13:37.463: vmx| Powering off Ethernet0
Mar 21 03:13:37.463: vmx| Hot removal done.



You are probably wondering… ok, but, how do I prevent such thing from happening on my environment ?

Easy, disabling  Hot Add/Remove on the virtual machine.

- power off the Virtual Machine
- Edit the setting of it
- On the options tab, click General
- Then click on Configuration Parametes
- click Add Row
- Insert the following item devices.hotplug with value of false
- close and save everything
- power the VM back on

And Yes, you need to perform this procedure on each Virtual Machine.

Luckily, on a VDI environment hundreds of virtual desktops are based on a single virtual machine. So, perform this step on the parent virtual machine and recompose the pool,  every virtual desktop will inherit this configuration.

Another Yes........ you will lose the capability of Hot Add/Remove devices on this virtual desktop, but, it’s not a thing you would need to be worried about on a VDI environment.

I hope this tip helps you preventing your users from losing connection from their virtual desktops and why not reducing the calls into your support : )


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I’m and IT specialist with over 15 years of experience, working from IT infraestructure to management products, troubleshooting and project management skills from medium to large environments. Nowadays I'm working for VMware as a Senior Consultant, helping customers to embrace the Cloud Era and make them succefully on this journay. Despite the fact I'm a VMware employee these postings reflect my own opnion and do not represents VMware's position, strategies or opinios.

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