Tag Archive for hot-add

Identify pre-requisites for Hot-Add Features

January 31, 2013 Objective 3 Tuning and Optimisation, Objective 6 Advanced Troubleshooting No comments

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What is Hot-Add?

Hot add options allow configuration changes to a virtual machine while it is powered on. Hot add options can be turned on or off for memory and number of CPU configurations for eligible virtual machines.

Hotadd

Pre-Requisites

  • You must disable CPU hot add if you plan to use USB device passthrough from an ESX/ESXi host to a virtual machine.
  • When you configure multi-core virtual CPUs for a virtual machine, CPU hot Add/remove is disabled.
  • Not enabled by default.
  • Check Guest OS support
  • Memory and CPUs can be hot added (but not hot removed)
  • Enabled per VM and needs a reboot to take effect
  • Enable on templates
  • Virtual H/W v7
  • Not compatible with Fault Tolerance

VMware Tools allows hot add/removal of NICs

October 19, 2012 VMware, VMware Tools No comments

We had an issue today where someone could do the following

  • Log into a server
  • Click on VMware Tools
  • Click on Devices
  • Look at NICs and un-tick them effectively turning off the NICs
  • As a result a complete loss of connectivity

The Solution

Please see the following KB:

Disabling the HotAdd/HotPlug capability in ESX/ESXi 4.x and ESXi 5.0 virtual machines
http://kb.vmware.com/kb/1012225

vSphere PowerCLI can be used to enable/disable hot-plug capability on all the virtual machines using this command below and you can do it while the machine is on but you will need to vMotion the VM afterwards to update/reorder the .vmx file

$vms = Get-VM (Your method of providing the VM name) $vms = Get-VM | Get-View $vmx = New-Object| Get-View $vmx = New-Object
$vmx.extraConfig += New-Object VMware.Vim.OptionValue
$vmx.extraConfig[0].key = “devices.hotplug”
$vmx.extraConfig[0].value = “false”
($vms.ID).ReconfigVM_Task($vmx)

Note: VMware do not support Scripting