WilliamLam.com

Exploring the Cloud-init Datasource for VMware GuestInfo using vSphere

by // 3 Comments

While exploring some upcoming capabilities and providing early feedback to Engineering, I came to learn about a new Cloud-init datasource called VMware GuestInfo that was recently merged into the project last August. The Cloud-init Datasource for VMware GuestInfo started out as an OSS project created by Andrew Kutz of VMware and it provides an easy way for a vSphere-based VM to leverage the popular Cloud-init tool for OS initialization and configuration. 

Unlike the recent vSphere Guest OS Customization with Cloud-init feature in vSphere 7.0 Update 3, the Cloud-init Datasource for VMware GuestInfo works by configuring specific guestinfo variables on a VM which are then transported into the guest operating system (GOS) using VMware Tools and is then processed by the cloud-init service that is running inside of the GOS. The nice thing about using this new Cloud-init datasource is that it is not tied to a specific release of vSphere and for those with Cloud-init experience, this is an easy way to incorporate your existing workflows. While I was somewhat familiar with Cloud-init and Linux GOS, I did not know that support for Microsoft Windows was also possible through the use of another project similiar to Cloud-Init called Cloudbase-Init.

It took me some time to figure out how to setup Cloudbase-init with Windows and I have to give a huge shoutout to Jay Vyas for pointing me over to one of his pet projects SIG Windows Development Environment that provided a clue to what the configuration file should look like. While learning about both Cloud-init Datasource for VMware GuestInfo and Cloudbase-init, I found that it was not trivial to get started and I wanted to document some concrete examples that can easily illustrate the power of this capability but also help anyone that might be interested in using this feature and how to quickly get started.

[Read more...]

Heads Up - Potential missing vCenter Server Events due to sequence ID overflow

by // 2 Comments

We had a few users who had reported issues with using the VMware Event Broker Appliance (VEBA) solution where VEBA was not receiving any events from the connected vCenter Server. This was really puzzling for the team to debug because the user clearly saw events in both the vSphere UI as well as using vSphere Automation Clients like PowerCLI.

After a bit of debugging with a few of our users (huge thanks to Michael Gasch for driving this), we discovered that in certain environments, the generated sequence number that is used for the vCenter Event ID has overflowed and causes the value to have a negative number. To further complicate the debugging, there are actually two ways of fetching vCenter Server Events using the vSphere API. The first is to just look at the LatestPage property, which will return the most recent events and not care about event ID and the second is to use CreateCollectorForEvents() which is more of an event stream and it does care about the event ID being non-negative. You can probably guess which vSphere API VEBA was using, not only because of our check-pointing feature but LatestPage could lose events from a client request point of view for chatty environments.

[Read more...]

Emulating a Virtual USB storage device using Nested ESXi

by // 3 Comments

My buddy Alan Renouf had pinged me earlier today and asked whether it was possible to emulate a USB storage device that could aide him in the testing the installation of ESXi from a USB device but without having to use a real USB device. I honestly was not aware of any mechanisms that would allow for this and I normally would just passthrough a real USB device to a Nested ESXi VM for this type of testing purposes.

While thinking about his question, I also recall we had made some enhancements to our Virtual USB interface that would allow user to back it using a disk file. While searching further, I came to learn that not only was this possible, but it was also a common method for testing USB-based installation without the hassle of messing with physical hardware. It turns out you can just present a Virtual Disk (VMDK) to a VM running ESXi (Nested ESXi) and through a special driver, it will recognize the device as a USB storage device!

I definitely wish I had learned about this earlier and it goes to show, all the hard engineering efforts made by our VMware Engineers to make testing and using our software as easy as possible even without needing real physical hardware 😀

[Read more...]