CKA in 2026 — troubleshooting is now the biggest domain
The Certified Kubernetes Administrator curriculum, its domain weightings, what changed, and why the exam rewards speed at the terminal more than knowledge.
Tag
Kubernetes
Every post tagged Kubernetes — practitioner notes from running Kubernetes, OpenShift and DevOps tooling in production for clients across the EU and the Gulf.
14 posts
The liveness probe that makes your uptime worse
Liveness, readiness and startup probes do different jobs. Conflating them is one of the few Kubernetes misconfigurations that actively causes outages.
Default-deny NetworkPolicy without breaking DNS
Locking a namespace to default-deny and adding traffic back safely, why DNS breaks first, and the selector mistake that silently allows far more than intended.
Security Context Constraints — why your Helm chart won't start
How OpenShift SCCs assign arbitrary UIDs, why that breaks images built for root, how to read the admission error, and how to fix it without granting anyuid.
OpenShift vs Kubernetes: what the extra layer buys you
The concrete differences between OpenShift and upstream Kubernetes — security defaults, routes, operators, builds — and when plain Kubernetes is the better call.
CKS — the Kubernetes security exam, and the CKA prerequisite trap
Curriculum weightings for the Certified Kubernetes Security Specialist, the prerequisite rule that is more ambiguous than people assume, and how to prepare.
CKAD — the Kubernetes exam for people who ship on it
Curriculum weightings for the Certified Kubernetes Application Developer, how it differs from CKA in character rather than difficulty, and how to prepare.
CKA, CKAD or CKS — which Kubernetes exam to take first
A side-by-side of the three CNCF Kubernetes certifications by cost, weighting and audience, plus the ordering constraint that decides it for most people.
OpenShift AI — what it is, and when it earns its licence
Red Hat OpenShift AI in plain terms, the platform problems it solves, and a straightforward test for whether your organisation needs it yet.
Requests and limits — CPU and memory are not analogous
What happens when a container exceeds its CPU limit versus its memory limit, why the two answers differ, and what that means for how you set them.
Horizontal Pod Autoscaler: why it scales late, or not at all
The requests dependency nobody mentions, how the HPA replica formula really works, stabilisation windows, and why CPU is the wrong signal for most queue workloads.
PodDisruptionBudgets: the reason your node drain hangs
What a PDB does and does not protect against, the single-replica trap that blocks upgrades forever, and how to set minAvailable so maintenance can still happen.
Why OpenShift upgrades stall, and how to clear them
Upgrade channels, MachineConfigPools and the four things that block a cluster upgrade, plus how to tell a slow upgrade from a stuck one before you intervene.
Routes or Ingress on OpenShift, and the three TLS modes
Edge, passthrough and re-encrypt termination compared, what each does to client certificates and HTTP headers, and when an Ingress object is the better choice.