Disable NIC in ESX VM using PowerCLI

I was trying to understand how CRLs work in IIS 6.0, see my previous two posts here and here and I was trying to prevent communication between the CA server and the application server. I was having to go into vSphere and modify the settings of the NICs (disconnecting them), which got tiring pretty soon. So, I thought I would try to do it from the ESX console and after a bit of digging I found that it should be doable with the vmware-cmd command, like this:

vmware-cmd myCAserver..vmx disconnectdevice ethernet0

Alas, this was the result:

Traceback (most recent call last):

  File "/usr/bin/vmware-cmd", line 88, in ?

    main()

  File "/usr/bin/vmware-cmd", line 63, in main

    operationName, result = CommandProcessor.Process(host, args)

  File "/usr/lib/vmware/vmware-cmd/CommandProcessor.py", line 11, in Process

    result = operation.DoIt(*processedArgs)

  File "/usr/lib/vmware/vmware-cmd/operations/DeviceOps.py", line 152, in DoIt

    device.SetConnected(False)

AttributeError: 'NoneType' object has no attribute 'SetConnected'

After a extra bit of googleing which failed to come up with a decent answer, I gave up and decided to give PowerCLI a try.

I launched PowerCLI from the start menu and connected to the VI server with:

Connect-VIServer viservername

Once Connected to the vcentre server I got both VMs and stored them in a variable with the following commands:

$CA = Get-VM –Name “myCAServer”

$app = Get-VM –Name “myAppServer”

I checked that this has grabbed the VM that I wanted by simply typing:

$CA

which returns:

Name                 PowerState Num CPUs Memory (MB)
----                 ---------- -------- -----------
myCAServer           PoweredOn  1        1024           

Since both Guests have only one NIC, I got the nic details and stored in a variable for use later:

$CAnic = Get-NetworkAdapter $CA

$appnic = Get-NetworkAdapter $app

Now I can use Set-NetworkAdapter to switch them on or off at will. To turn off the CA Server’s NIC:

$CAnic = Set-NetworkAdapter –NetworkAdapter $CAnic –confirm:$false –connected:$false

And then back on:

$CAnic = Set-NetworkAdapter –NetworkAdapter $CAnic –confirm:$false –connected:$true

I can now check the status with:

$CAnic.ConnectionState

which returns:

         AllowGuestControl                  Connected            StartConnected
         -----------------                  ---------            --------------
                      True                      False                      True

Remember that command completion works pretty well, so you could just type $CAnic. And then keep pressing TAB. Similarly, if you are unsure about the switches for a cmdlet, just type - and then TAB through the options.

It is also possible to pipe commands so that you don't need to use several variables, e.g.

$CAnic = Get-VM -Name "myCAServer" | Get-NetworkAdapter | Set-NetworkAdapter -Connected:$false -confirm:$false

I still use a variable, so that I can easily check the status of the NIC, but it's not necessary, I could have simply used:

 Get-VM -Name "myCAServer" | Get-NetworkAdapter | Set-NetworkAdapter -Connected:$false -confirm:$false

I find that using variables is easier for a beginner such as myself. At any rate, I'm glad I've given PowerCLI a go as it is really good.