102 comments on “Kubernetes horizontal POD Autoscaling – Hello World”

Kubernetes horizontal POD Autoscaling – Hello World

For a quick test of horizontal autoscaling of an NginX deployment, we need the following ingredients: a metrics server installation to be able to measure the POD's CPU an nginx deployment with a CPU reservation an auto scaler configuration a…

55 comments on “How I earned the Certified Kubernetes Administrator (CKA) badge – what would I do differently today?”

How I earned the Certified Kubernetes Administrator (CKA) badge – what would I do differently today?

What is the CKA? The Certified Kubernetes Administrator (CKA) certification proves you have hands-on experience managing Kubernetes clusters. How did I learn Kubernetes? Three years ago, I purchased a 4-day classroom Kubernetes Administration course (LFS458) from FastLane. It was not…

70 comments on “Kubernetes etcd backup and restore – cheat sheet”

Kubernetes etcd backup and restore – cheat sheet

This is a cheat sheet on how to perform backup&restore of the etcd server in kubernetes quickly. Test this on Killercoda Play with Kubernetes tl;dr Find reference: https://kubernetes.io --> Documentation --> Search "etcd backup restore" --> you will find: Operating etcd…

59 comments on “Cheat Sheet: Install non-privileged podman v3 in a CentOS 7 Container”

Cheat Sheet: Install non-privileged podman v3 in a CentOS 7 Container

See how you can run a user space podman container inside another non-privileged container. For that, we create a CentOS 7 image with podman v3 installed. We spin up a Kubernetes non-privileged container from this image, and we show that…

62 comments on “Migrate Kubernetes Runtime from Docker to containerd”

Migrate Kubernetes Runtime from Docker to containerd

Migration of the kubeadm-based Kubernetes from Docker to containerd should be easy. In my case, it wasn't. Wrong information found on the Internet combined with the incompatibility of the used Kubernetes and containerd versions has caused major problems. Fortunately, I…

1 comment on “CKA Labs (17): Kubernetes Readiness and Liveness Probes”

CKA Labs (17): Kubernetes Readiness and Liveness Probes

In this article,  we will learn how Kubernetes Liveness Probes and Kubernetes Readiness Probes help us improve the continuity and availability of Kubernetes Services. For that, we will learn how Kubernetes uses probes to decide, whether an application is up…

1 comment on “CKA Labs (8) — Kubernetes ReplicaSets”

CKA Labs (8) — Kubernetes ReplicaSets

In this lab, we will have a closer look at Kubernetes Replicasets. First, we will learn how ReplicaSets control, how many POD replicas are up and running at any time. We will learn, how ReplicaSets and PODs are connected: via labels. We will show that manually creating PODs with matching labels can have weird cuckoo's eggs effects. Moreover, a POD can be detached from a ReplicaSet without stopping it by manipulating its label.