I recently noticed a trend of questions from various users about extracting specific bits of information such as the version of ESXi that's running or the MoRef ID of the VM, all while within the guestOS. I had already written an article about this topic awhile back called How to extract host information from within a VM? but it seems like there is still a continued interest to easily obtain this information about the underlying vSphere infrastructure from within the guestOS.
I came across another method while researching a different topic which is to use the vApp property of a VM called the OVF runtime environment. This is a feature that has been around since the early days of vSphere 4.x, if not earlier which provides a mechanism to retrieve some of this information as well as custom properties. The OVF feature provides users with the capability to pass in any type of metadata information such as application start up parameters, network configuration, password management, etc. directly into the guestOS for flexible guest customization.
The OVF runtime environment is only available while the VM is powered and it can be accessed from either VMware Tools or from a special ISO that is mounted to the guestOS CD-ROM device. To enable the OVF runtime environment, you just need to perform these two simple steps:
1. Edit your VM and select the Options tab and enable the vApp Options:
2. Under the OVF Settings, specify the how you want to access the OVF environment by either VMware Tools or ISO Image transport:
If you are interested in enabling this using the vSphere API, take a look at the vAppConfig property. You can enable OVF runtime environment on a running VM, but the changes will not go into effect until the VM has been completely powered off and then powered back on, a guestOS reboot will not suffice.
After the settings have been applied, go back into the OVF Settings for a powered on VM and you now should be able to click on the "View" button which will show you the OVF runtime environment for that particular VM.
For a vanilla VM, you should see three basic things:
- The vCenter MoRef of the VM (vApp property is only available with vCenter and not on a standalone ESXi host)
- The hypervisor name and version
- The network (Portgroup/Distributed Portgroup) the VM is connected to
To retrieve this same information from within the guestOS you have two options:
Run the following command:
vmtoolsd –cmd "info-get guestinfo.ovfenv"
Below are two examples for both a Linux and Windows VM:
Mount the CD-ROM in the guestOS and inside you will find the ovf-env.xml file which contains the OVF runtime environment information.
As I mentioned earlier, you can also create custom key/value properties which can then be accessed by the guestOS VM. If you go to Advanced section and click on the Properties button, you will be able to add your own custom properties. Below is a screenshot of adding three customer properties called: application_owner, startup_option and system_owner just to give you an idea of the possibilities.
The OVF runtime environment does not just stop with vSphere, but it is also available to VMs running in vCloud Director. The only requirement is that vCloud Director VMs has the vApp options enabled at the vSphere layer as noted earlier. Below is a screenshot for a VM that has been imported into vCloud Director from vSphere and you will notice some additional "vCloud Director" specific properties.
Even though the OVF runtime environment makes it easier to retrieve some of these "underlying" infrastructure details, I am still interested in some of the use cases where you would need to know the hypervisor version or MoRef ID from within the guestOS. If you are currently requiring this or other bits of information, please leave a comment about your particular use case.