Category Archives: Azure

Detecting SNAT port exhaustion on Azure Kubernetes Service

Running applications on an Azure Kubernetes Service cluster which make a lot of outbound calls might led to a SNAT port exhaustion. In today’s blog article I walk you through how to detect and mitigate a SNAT port exhaustion on AKS. What is a SNAT port exhaustion? It is important to know what a SNAT port exhaustion is to apply the correct mitigation. SNAT, Source Network Address Translation, Read more [...]

Distribute your application across different availability zones in AKS using Pod Topology Spread Constraints

This is the last blog post of a series of posts covering the topic about increasing the application availability on Azure Kubernetes Service / Kubernetes. Today we cover the pod topology spread constraints. What are pod topology spread constraints? In the first post of the series, I talked about the pod disruption budget. The PDB guarantees that a certain amount of your application pods is available. The Read more [...]

Run the Envoy Proxy ratelimit service for Istio on AKS with Azure Cache for Redis

The Istio sidecar proxy uses Envoy and therefore supports two different rate limiting modes. A local one targeting only a single service and a global one targeting the entire service mesh. The local rate limit implementation only requires Envoy itself without the need for a rate limit service. In contrast the global rate limit implementation requires a rate limit service as its backend. Looking Read more [...]

Evaluating Gatekeeper policies with the Rego Playground

Writing and evaluating Gatekeeper policies can be hard sometimes. Especially the testing part of a newly created policy. There are different approaches to tackle this like having a dedicated test Kubernetes cluster for it. An alternative we used was a script starting a single node KinD cluster on Docker for Mac and installing Gatekeeper onto it. The advantage of this approach you see how the Read more [...]

Increase your application availability with pod anti-affinity settings in Azure Kubernetes Service

This is the second blog post of a series of posts covering the topic about increasing the application availability on Azure Kubernetes Services / Kubernetes. Today we cover the pod anti-affinity setting. What is the pod anti-affinity? In the first post of the series, I talked about the PodDisruptionBudget. The PDB guarantees that a certain amount of your application pods is available. Defining Read more [...]

Azure Kubernetes Service – Azure RBAC for Kubernetes authorization

At this year’s Ignite conference Microsoft announced the next major step of integrating Azure functionality into AKS: Azure RBAC for Kubernetes authorization. -> https://docs.microsoft.com/en-us/azure/aks/manage-azure-rbac Azure RBAC for Kubernetes authorization lets you assign built-in or custom roles onto the Azure Kubernetes Service object in Azure. So, you do not have to create Kubernetes Read more [...]

Increase your application availability with a PodDisruptionBudget on Azure Kubernetes Service

This is the first blog post of a series of posts covering the topic about increasing the application availability on Azure Kubernetes Service / Kubernetes. Today we cover the PodDisruptionBudget. What is a PodDisruptionBudget? A PDB is an additional Kubernetes object that is deployed beside your Deployment, ReplicaSet or StatefulSet increasing your application’s availability. This is done by Read more [...]

Azure Reservations and the RBAC dilemma

Cloud computing underlies a constant change. Things you take today for granted are different tomorrow. Surprisingly, even designs and implementations on the same platform can be different. Welcome to today’s topic of Azure Reservations and the RBAC dilemma. As I have written in my brief introduction, designs and implementations can be different. Azure RBAC is one example here. Being the owner Read more [...]

Troubleshooting Azure Kubernetes Service tunnel component issues

In Azure Kubernetes Service Microsoft manages the AKS control plane (Kubernetes API server, scheduler, etcd, etc.) for you. The AKS control plane interacts with the AKS nodes in your subscription via a secure connection that is established through the tunnelfront / aks-link component. -> https://docs.microsoft.com/en-us/azure/aks/concepts-clusters-workloads#kubernetes-cluster-architecture As Read more [...]

Automate taking backups from Azure disks attached to Azure Kubernetes Service

At the beginning of 2019 I wrote a blog post about taking backups from Azure disks attached to an Azure Kubernetes Service cluster. -> https://www.danielstechblog.io/taking-backups-from-azure-disks-attached-to-aks-via-azure-automation/ Since then, some things changed. Azure Function PowerShell support went into public preview in April 2019 and the AzTable (AzureRmStorageTable) module I use Read more [...]