HashiCorp Vault Intermediate CA Setup with Cert-Manager and Microsoft Root CA

In this post, we’ll explore how to set up HashiCorp Vault as an Intermediate Certificate Authority (CA) on a Kubernetes cluster, using a Microsoft CA as the Root CA. We’ll then integrate this setup with cert-manager, a powerful Kubernetes add-on for automating the management and issuance of TLS certificates.

The following is an architecture diagram for the use case I’ve built.

• A Microsoft Windows server is used as the Root CA of the environment.
• A Kubernetes cluster hosting shared/common services, including HashiCorp Vault. This is a cluster that can serve many other purposes/solutions, consumed by other clusters. The Vault server is deployed on this cluster and serves as an intermediate CA server, under the Microsoft Root CA server.
• A second Kubernetes cluster hosting the application(s). Cert-Manager is deployed on this cluster, integrated with Vault, and handles the management and issuance of TLS certificates against Vault using the ClusterIssuer resource. A web application, exposed via ingress, is running on this cluster. The ingress resource consumes its TLS certificate from Vault.

Prerequisites

• Atleast one running Kubernetes cluster. To follow along, you will need two Kubernetes clusters, one serving as the shared services cluster and the other as the workload/application cluster.
• Access to a Microsoft Root Certificate Authority (CA).
• The Helm CLI installed.
• Clone my GitHub repository. This repository contains all involved manifests, files and configurations needed.

Setting Up HashiCorp Vault as Intermediate CA

Deploy Initialize and Configure Vault

Install the Vault CLI. In the following example, Linux Ubuntu is used. If you are using a different operating system, refer to these instructions.

TKG: Updating Pinniped Configuration and Addressing Common Issues

Most of the TKG engagements I’ve been involved in included Pinniped for Kubernetes authentication. On many occasions, I have seen issues where the configuration provided to Pinniped was incorrect or partially incorrect. For example, common issues may be related to the LDAPS integration. Many environments I have seen utilize Active Directory as the authentication source, and Pinniped requires the LDAPS certificate, username, and password, which are often specified incorrectly. Since this configuration is not validated during the deployment, you end up with an invalid state of Pinniped on your management cluster.

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!).

Backstage Introduction, KubeCon & CloudNativeCon Europe 2022

Thanks to TeraSky’s education program, I recently attended KubeCon & CloudNativeCon Europe 2022 in Valencia, Spain.

The experience was incredible. While there were many interesting technical sessions on many exciting topics, I was most curious about Backstage - which has sparked my interest ever since I started exploring VMware Tanzu Application Platform (TAP).

I decided to attend a session entitled “Backstage: Restoring Order to Your Chaos”, given by Spotify software engineer Dave Zolotusky. Going into the session, I was stunned by the huge line of people trying to get into the room. That was something I had never seen before in any other session. Fortunately, I was lucky enough to secure one of the last seats.

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.