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Use node initialization taints on Azure Kubernetes Service with Cilium
On an Azure Kubernetes Service cluster with Bring Your Own Container Network Interface (BYOCNI) using Cilium, you could not use Cilium’s agent-not-ready taint functionality. -> https://docs.cilium.io/en/stable/installation/taints/ The reason for that is that the Azure control plane blocks add/remove operations on taints via the Kubernetes API. You have to remove taints via the Azure Kubernetes Service…
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Cilium’s new Hubble flow policy log field
Cilium in version 1.18 introduced a new useful feature called “policy log field” for Hubble flows. -> https://isovalent.com/blog/post/cilium-1-18/#hubble-flow-policy-log-field This feature provides additional possibilities for further insights/checks on which network policy was applied to a network flow. We have a look at how to configure the policy log field and what a Hubble flow looks like…
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Deploy Azure DNS security policies via Terraform
Today, I walk you through a new feature that has been released this year: Azure DNS security policies. -> https://azure.microsoft.com/en-us/updates?WT.mc_id=AZ-MVP-5000119&id=497535 Azure DNS security policies allow you to get insights into your DNS traffic at the Virtual Network level. The two main use cases for DNS security policies are blocking name resolution of known or malicious…
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Restrict access to the IMDS endpoint on Azure Kubernetes Service with Cilium
In today’s blog post, we take a look at restricting access to the Azure IMDS endpoint on an Azure Kubernetes Service (AKS) cluster with Cilium using the BYOCNI approach. The Instance Metadata Service (IMDS) endpoint, also known as short IMDS, can be called directly from every Azure VM or VMSS instance via the following command.…
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How to restore a container image from an Azure Kubernetes Service node to an Azure Container Registry?
Imagine a specific version of your container image used for your application has been deleted from your Azure Container Registry. It cannot be restored for whatever reason through your CI/CD pipeline, and you still need this version. How can you restore that specific version when you still have a running pod on one of the…
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Kubernetes namespace exclusion options for Kyverno policies
During my preparation for the Kyverno Certified Associate exam, I hit an interesting part that I would like to talk about today. Which options do we have to exclude entire namespaces from Kyverno policies? Depending on what we want to achieve, we have three different options at hand to accomplish our goal. Option 1 –…