Fat-Finger Hero

There is risk when it comes to configuring the various items that make up a virtualized infrastructure. What do you do when things go wrong? Ideally, there are protections in place to prevent configuration errors from causing you extra work or, even worse, a new install of a host. Here are a few things you can do to protect ahead of the curve for VMware environments:

Scripted configuration: For port group and standard virtual switch configuration, the esxcfg-vswitch command will allow you repeat configuration on many hosts.

Host Profiles: For vSphere environments, host management can be managed through configuration on a number of hosts. This configuration can configure storage, networking, security settings and other aspects of ESX and ESXi hosts.

VI3 networking configuration: The ITQ VLAN and port group manager tool is used to configure networking in VI3 environments.

But what about other situations when the inevitable fat-finger entry occurs? One of the most common things that I have fat-fingered is a VLAN configuration. For things like virtual machine port groups and vmkernel interfaces, this is usually an easy correction when things are determined to be corrected improperly. It gets more complicated with the service console VLAN, IP address or other configuration that prevents you from accessing the system occurs.

Here is an example: I configured the service console of an ESX server with an incorrect VLAN, yet with the correct IP address. While it is a good idea to separate roles with VLANs, I need to use the right VLAN! A way around this without rebuilding the host (as in most cases you can't access it with this configuration) is to create a virtual machine port group on the incorrect VLAN. On that port group, then place a virtual machine and configure its network configuration to be on that IP network that the 'orphaned' host is located. Then, use that virtual machine to run the vSphere client to directly configure the service console correctly (change the VLAN to the correct entry). At that point, the host will resume its correct place on the intended VLAN. This can be especially helpful if you are not on site and have an orphaned host that needs to be reconfigured.

How have you recovered from misconfigured elements of your virtual environment? Share your comments here.

Posted by Rick Vanover on 01/14/2010 at 12:47 PM