May 19, 2020

Kubernetes RBAC explained

Introduction Whether it is from CI/CD or from the command-line, I often see the default kube-config with cluster-admin rights being used. This is like permanently working with root privileges and there certainly are more secure ways. In this post we will look into demystifying Kubernetes RBAC, and setting-up more suitable permissions for two use-cases: a CI/CD pipeline that needs full permissions on anything located in a given Namespace a reader who needs to access resources for troubleshooting purposes Concepts Roles and ClusterRoles define sets of permissions to objects at the namespace and cluster scope. Read more

May 18, 2020

Kubernetes policies with Gatekeeper

Introduction Gatekeeper is a validating webhook that enforces CRD-based policies executed by Open Policy Agent. In a previous post, we went into details about OPA: this post superseeds it. The differences between OPA and Gatekeeper are listed here. In this post we will explore Gatekeeper and start with implementing a policy to enforce a given label to be present at the namespace level. In future posts coming soon we will implement policies as described here: Read more

May 11, 2020

SSH login with yubikey using PIV

Introduction This article will take you through setting-up a yubikey to hold your SSH private key. It assumes that you have a PIV-enabled yubikey: PIV, or FIPS 201, is a US government standard. It enables RSA or ECC sign/encrypt operations using a private key stored on a smartcard (such as the YubiKey NEO), through common interfaces like PKCS#11. PIV is primarily used for non-web applications. It has built-in support under Windows, and can be used on OS X and Linux via the OpenSC project. Read more

May 3, 2020

Building docker images for multiple architectures

Introduction Since Kubernetes runs on the Raspberry PI I have been investigating ways to build my blog so that it can run on my x86 (Proxmox) as well as ARM Kubernetes cluster, composed of Raspberry PIs and an Nvidia Jetson Nano. This post will take you through my learnings of the taxonomy of architectures and platforms, as well as building docker images for multiple architectures. Architectures Well, I already knew that rpi has a different architecture than my Intel-based hardware, so let’s get into how these are named. Read more

May 2, 2020

Understanding Kubernetes' pod lifecycle: the readiness probe

Introduction Understanding Kubernetes' concepts is key to running highly available applications. This article will take you through the scenario of deploying a new version of a pod, and show how understanding the pod lifecycle and implementing a readiness probe will help you deploying new releases without downtime. Without a readiness probe Kubernetes will try to guess when your pod is ready, and then schedule traffic to it. If the pod has latency between the point-in-time when the container is running and when it can handle traffic, this will cause transactions to be dropped, a. Read more

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