Streamlining and Customizing Windows Image Builder for TKG

Tanzu Kubernetes Grid (TKG) is one of the few platforms providing out-of-the-box support and streamlined deployment of Windows Kubernetes clusters. VMware is actively investing in this area and constantly improving the support and capabilities around Windows on Kubernetes.

Unlike Linux-based clusters, for which VMware provides pre-packaged base OS images (typically based on Ubuntu and Photon OS), VMware cannot offer Windows pre-packaged images, primarily due to licensing restrictions, I suppose. Therefore, building your own Windows base OS image is one of the prerequisites for deploying a TKG Windows workload cluster. Fortunately, VMware leverages the upstream Image Builder project - a fantastic collection of cross-provider Kubernetes virtual machine image-building utilities intended to simplify and streamline the creation of base OS images for Kubernetes.

Tanzu Kubernetes Grid GPU Integration

I recently had to demonstrate Tanzu Kubernetes Grid and its GPU integration capabilities. Developing a good use case and assembling the demo required some preliminary research.

During my research, I reached out to Jay Vyas, staff engineer at VMware, SIG Windows lead for Kubernetes, a Kubernetes legend, and an awesome guy in general. :) For those who don’t know Jay, he is also one of the authors of the fantastic book Core Kubernetes (look it up!).

Getting Started with Carvel ytt - Real-World Examples

Over the years of working with Tanzu Kubernetes Grid (TKG), one tool has stood out as a game-changer for resource customization: Carvel’s ytt. Whether tailoring cluster manifests, customizing TKG packages, or addressing unique deployment requirements, ytt has consistently been a fundamental part of the workflow. Its flexibility, power, and declarative approach make it an essential tool for anyone working deeply with Kubernetes in a TKG ecosystem.

But what exactly is ytt? Short for YAML Templating Tool, ytt is part of the Carvel suite of tools designed for Kubernetes resource management. It provides a powerful, programmable approach to templating YAML configurations by combining straightforward data values, overlays, and scripting capabilities. Unlike many traditional templating tools, ytt prioritizes structure and intent, making it easier to maintain, validate, and debug configurations—particularly in complex, large-scale Kubernetes environments.

Harbor Registry – Automating LDAP/S Configuration – Part 2

This post continues our two-part series on automating LDAP configuration for Harbor Registry. In the previous post, we demonstrated how to achieve this using Ansible, running externally. However, external automation has its challenges, such as firewall restrictions or limited API access in some cases/environments.

Note: make sure you review the previous post as it provides a lot of additional background and clarifications on this process, LDAPS configuration, and more.

Here, we explore an alternative approach using Terraform, running the automation directly inside the Kubernetes cluster hosting Harbor. This method leverages native Kubernetes scheduling capabilities for running the configuration job in a fully declarative approach and does not require any network access to Harbor from the machine running the job.

Replacing your vCenter server certificate? TKG needs to know about it…

I recently ran into an issue where TKGm had suddenly failed to connect to the vCenter server.

The issue turned out to be TLS-related, and I noticed that the vCenter server certificate had been replaced…

Due to the certificate issue, Cluster API components failed to communicate with vSphere, causing cluster reconciliation to fail, among other vSphere-related operations.

Since all TKG clusters in the environment were deployed with the VSPHERE_TLS_THUMBPRINT parameter specified, replacing the vCenter certificate breaks the connection to vSphere, as the TLS thumbprint changes as well.

Upgrading NSX ALB in a TKG Environment

For quite a long time, the highest version of the NSX ALB TKG supported was 20.1.6/20.1.3, although 21.1.x has been available for a while, and I have been wondering when TKG would support it. In the release notes of TKG 1.5.4, I recently noticed a note that has been added regarding NSX ALB 21.1.x under the Configuration variables section:

AVI_CONTROLLER_VERSION sets the NSX Advanced Load Balancer (ALB) version for NSX ALB v21.1.x deployments in Tanzu Kubernetes Grid.

Customizing Elasticsearch indices using Fluent-Bit in TKG

Fluent-Bit is currently the preferred option for log shipping in TKG and is provided out of the box as a Tanzu package that can be easily deployed on each TKG/Kubernetes cluster.

A recent implementation required shipping all Kubernetes logs to Elasticsearch, complying with a specific naming convention for the Elasticsearch indices.

Applying such customizations requires you to utilize the Lua filter. Using the Lua filter, you can modify incoming records by invoking custom scripts to apply your logic when processing the records.