Kubernetes

Site Reliability Engineering (SRE) may sound like a fancy job title, but it’s actually one of the most practical and important roles in modern infrastructure and software teams. What is an SRE? SRE stands for Site Reliability Engineer. In simple terms, an SRE ensures that systems are reliable, scalable, and efficient. The concept was born at Google, where software engineers were tasked with running production systems using software engineering principles. ...

K3s vs MicroK8s: Lightweight Kubernetes Showdown Need Kubernetes but without the heavy machinery? That’s where K3s and MicroK8s shine. Let’s break them down in a simple and friendly way. What Are They? K3s – A lightweight Kubernetes distribution by Rancher, designed for IoT, edge, and low-resource environments. MicroK8s – A snap-based Kubernetes distro from Canonical (Ubuntu), easy to install and manage. Why Use Them? Feature K3s MicroK8s Size <100MB ~200MB Install Single binary snap install microk8s Resource usage Very low Low High availability Yes (with some config) Yes (built-in clustering) OS compatibility Linux (only) Linux, Windows (some support) Add-ons Helm, Traefik (default), etc. Built-in add-ons (microk8s enable) Installation K3s: curl -sfL https://get.k3s.io | sh - MicroK8s: sudo snap install microk8s --classic Use Cases K3s: Great for edge computing, Raspberry Pi clusters, or minimal VMs. MicroK8s: Ideal for local development, CI/CD pipelines, and Ubuntu-based systems. Pros and Cons K3s Pros: ...

Common kube-apiserver Errors and How to Fix Them If you’re working with Kubernetes long enough, you’ll eventually run into strange behavior — and often the root cause is hidden inside the kube-apiserver. This component is the front door to your cluster, handling all requests and coordinating most actions. When it goes wrong, it can affect everything. Let’s look at common issues with the kube-apiserver and what to do about them. ...

CoreDNS is one of those quiet heroes in your Kubernetes cluster. It doesn’t get much attention—until DNS stops working, and suddenly everything breaks. Let’s understand how it works — simply. What Is CoreDNS? CoreDNS is the default DNS server in Kubernetes. It’s what helps your pods resolve names like my-service.default.svc.cluster.local to an actual IP address. It’s not just a DNS server. It’s modular, pluggable, and built for cloud-native environments. Why Is DNS Needed in Kubernetes? In Kubernetes, everything is dynamic: ...

Why Add a Custom DNS Zone? Adding a custom DNS zone in CoreDNS can be useful for: Internal testing (e.g., *.local or *.internal) Service discovery for non-Kubernetes services Custom mappings and overrides Step-by-Step Guide 1. Edit the CoreDNS ConfigMap kubectl -n kube-system edit configmap coredns Add a new zone block like this: apiVersion: v1 kind: ConfigMap metadata: name: coredns namespace: kube-system data: Corefile: | .:53 { errors health kubernetes cluster.local in-addr.arpa ip6.arpa { pods insecure fallthrough in-addr.arpa ip6.arpa } forward . /etc/resolv.conf cache 30 loop reload loadbalance } internal.test:53 { hosts { 10.10.10.10 service1.internal.test 10.10.10.11 service2.internal.test fallthrough } } 2. Restart CoreDNS kubectl -n kube-system rollout restart deployment coredns 3. Test the Zone From any pod: ...