26 September 2026
My blog's API is an Azure Container App that scales to zero, with a 30 second cold start. How three layers of caching keep readers from ever waiting on it: a stale-while-revalidate cache in a Cloudflare Worker, a durable KV fallback for Cloudflare's per-colo cache, and Cosmos DB Change Feed pushes so reads stop waking the container at all. With real monthly costs, and the trade-offs I accepted instead of solving.
17 September 2026
My blog counter went through three implementations in a week: fetching the whole article list to count it, a dedicated count endpoint that still cold-started the backend, and a Cosmos DB Change Feed keeping a Cloudflare KV value current so the read never touches origin. Plus a debugging story about one secret with three different names.
10 September 2026
How I added a moderated comment system to this blog: Cosmos DB's own Change Feed as the queue, an Azure Function scoring comments via Cloudflare Workers AI, least-privilege RBAC kept out of the CI pipeline on purpose, several real bugs found the hard way in production, and a mid-flight model upgrade after the small LLM proved unreliable.
1 September 2026
Two weekend side projects: training a first YOLO object-detection model with Ultralytics, and building a browser-accessible Linux practice lab on Azure Container Apps.
1 September 2026
I built a write API so Claude can create and update blog posts directly — and fixed a same-day production bug it uncovered along the way.
25 August 2026
I extended my Hangman demo with Claude Code so a human player can guess letters alongside the two LLM agents.
22 August 2026
A CKA lab automation tune-up: fixing a resource-group permission bug, splitting node provisioning, adding missing kubeadm prerequisites, and two new scripts that make starting and connecting to the practice cluster much smoother.
20 August 2026
Building a fully automated two-node Kubernetes cluster in an Azure sandbox for CKA practice — Calico CNI, VXLAN networking, and the IP-forwarding gotcha that broke cross-node pod connectivity until it was fixed.
18 August 2026
Kicking off CKA prep after five years running AKS in production — why hands-on install/config is the real gap to close, and the plan to build a two-node Kubernetes lab on Azure VMs inside a Whizlabs sandbox.
17 August 2026
A weekend recap: finally setting up Claude Code inside a Docker container, working through a Claude course, adding a human-playable mode to the hangman demo, and digging into CKA prep with a two-node Kubernetes cluster on Azure VMs.
11 August 2026
A quick Azure Cloud Shell habit: searching .bash_history or PowerShell's history file directly in the editor with Ctrl+F instead of trying to remember exact command syntax.
10 August 2026
A milestone for the V2 Capacity Advisor: real Azure Monitor alerts now flow through a webhook into AKS, get historical context from Table Storage, and come out the other side as LLM-generated, operator-friendly capacity recommendations.
3 August 2026
A small side project: an Azure Container Apps Job that checks a child's YouTube channel on a schedule via the YouTube API and emails a parent through Azure Communication Services the moment a new public video appears.
27 July 2026
The origin story for the Capacity Advisor: born from real throttling alerts, first shipped as a live ACA demo, now extended to evaluate node fit and cluster headroom on AKS too.
22 July 2026
Building a live Capacity Advisor demo over the holidays: an agent that collects Azure Container Apps metrics and asks a Cloudflare Llama model whether the configured resources are actually sufficient, with a real-time SignalR log stream.
20 July 2026
GitHub's move to immutable owner/repo IDs in the OIDC subject claim broke older Azure federated-credential trust policies — the fix is configuring Entra ID's 'Other issuer' option with the full subject string by hand, since the GitHub preset can't express the new @id format.
5 July 2026
After a seventh Microsoft certification in a row, taking a short break to turn a backlog of practical Kubernetes, debugging, and Linux tips into posts over the coming weeks — with a unit-testing series planned after that.
3 July 2026
Seven Microsoft certifications in a year, capped off with AZ-305: the actual order taken vs. the order recommended in hindsight, and why AZ-104 → AZ-305 back-to-back makes the most sense.
30 June 2026
Turning AZ-900 study notes into a short, scannable cheat sheet built around mental models and quick comparisons (IaaS/PaaS/SaaS, CapEx vs OpEx, Azure Policy vs Blueprints, storage redundancy) rather than a giant study dump.
27 June 2026
Passing the Whizlabs AZ-305 final practice test at 76.36% on the first attempt — solid validation across identity, governance, data solutions, and resilient architecture before the real exam.
22 June 2026
A condensed AZ-104 cheat sheet from exam notes: NSG vs ASG, storage RBAC vs SAS gotchas, VNet move limitations, Recovery Services Vault restrictions, and other exam traps around networking and resource moves.
19 June 2026
Six ways to troubleshoot pod-to-pod connectivity in Kubernetes when the usual tools are missing: curl, nc, wget, a bash /dev/tcp port check, a raw HTTP request via bash redirection, and a PowerShell/.NET fallback for Windows containers.
17 June 2026
A career-reflection post: 26 years after an Electrical Engineering/Telecommunications diploma, tying that original network-management background back into today's Azure networking and AZ-305 prep — DevOps as the bridge between the two.
16 June 2026
AKS's default max-pods-per-node (30 for user node pools) is set at node-pool creation time and can't be changed later — why bumping it to 150 up front makes sense on a subnet with plenty of IP headroom.
15 June 2026
An AZ-204 cheat sheet covering Durable Functions patterns, Azure Functions tiers, service tiers/limits, storage tiers, load balancer choices, and API Management policies — still ~80% relevant despite AZ-204's planned retirement in favor of AI-200.
10 June 2026
Why building a personal website during AZ-400 prep was one of the best calls made: real custom domains, TLS, and production-like deployments for demos turned abstract Azure concepts into a genuine portfolio.
9 June 2026
14k impressions and 88 reactions on a post about the AZ-400 lab's unclear instructions — including one comment from someone who failed the exam for the same reason, which is exactly why the AZ-400 cheat sheet followed the next day.
4 June 2026
Renewing AZ-204 in about 30 minutes on memory alone, right after passing AZ-400 — next up, full focus on AZ-305's architecture and governance content.
1 June 2026
The original Hangman demo launch: two Cloudflare Qwen2.5 LLM agents playing against each other, containerized on Azure Container Apps, served by a Cloudflare Worker, with real-time output over SignalR — evolved from an earlier AI-102 console practice project.
29 May 2026
Six Microsoft certifications in twelve months of evenings and weekends, capped by an 863/1000 score on AZ-400 — the certification order so far, and AZ-305 up next.
24 May 2026
When Whizlabs and Tutorials Dojo hadn't caught up to the April 2026 AZ-400 exam update (hybrid CI/CD, GitOps with Flux v2 + ArgoCD), generating custom scenario questions with AI to fill the gap — including one where the AI itself got a nuanced hybrid setup wrong first.
23 May 2026
80% on the Whizlabs AZ-400 final mock, first attempt, 5 days before the real exam — solid improvement from earlier practice tests after focusing hard on weak areas.
19 May 2026
Building the blue/green + feature-flag demo for AZ-400 practice: adding a user header, moving a feature from an env variable to an App Configuration flag — and the real debugging story, a 502 traced to GitHub Actions mangling a multi-line prompt.
11 May 2026
Cutting first-click latency on the Text Analysis demo by 5-10 seconds: a Cloudflare Worker checks KV on page load and invisibly prefetches/warms the Azure Container Apps backend if it's been idle more than 5 minutes.
7 May 2026
The build log for koorevaar.com itself: three evenings from buying the domain to a portfolio built with Aider+Qwen2.5, GitHub Actions pipelines, and a Terraform-deployed Azure Container Apps text-analysis demo behind a Cloudflare Worker + phi3:mini.
29 April 2026
Foundry Local reaching GA raised hopes for a real Ollama replacement on Intel GPU — but both tested OpenVINO models hard-capped responses at 199 tokens regardless of the configured max_tokens, a blocker for agentic coding workflows like Aider.
27 April 2026
A permanent, always-HTTPS demo domain that costs almost nothing when idle: a Cloudflare Worker + KV serves a static placeholder page, then instantly re-routes to a freshly provisioned AKS backend the moment a new ephemeral demo starts.
26 April 2026
The first working blue-green deployment on AKS for AZ-400 practice: three pipelines split across infrastructure provisioning, deployment, and Traefik IngressRoute-based promotion between two Git-branch environments.
25 April 2026
Adding a detect-language endpoint to the sentiment API, backed by AI-assisted unit tests (Aider + Qwen) that also run on main, a feature-branch flow set up for blue-green then canary, and a Flask route-ordering gotcha (routes must be defined before the blocking app.run() call).
11 April 2026
From sandbox success to a full CI/CD pipeline in a day: Terraform for AKS, Spot nodepools, a clean LLM-adapter pattern, Traefik on ARM64, ConfigMap-driven prompts, and a cross-subscription, bootstrap-plus-main-stage pipeline — all on €45 of remaining credits.
10 April 2026
The first working milestone: a self-hosted sentiment-analysis service running in the Whizlabs AKS sandbox — Terraform + PowerShell automation, a multi-container Ollama/LLM-adapter/Flask architecture, and ConfigMap-driven prompts with proper health probes.
5 April 2026
Kicking off a self-hosted LLM sentiment-analysis platform on AKS: a Flask API, an LLM adapter layer, Ollama (phi3:mini) in-cluster, Terraform for IaC, and Traefik ingress via Helm — the plan before any of it exists yet.
24 February 2026
Update #2 of an AKS ingress migration saga: rolling back from F5's OSS NGINX Ingress after its strict host-collision rules broke same-hostname HTTP+HTTPS routing, with Traefik lined up as the next (hopefully final) attempt.
19 February 2026
Why AGIC (and even the newer AGC) is a bad fit for anything beyond basic HTTP/HTTPS in AKS: it silently wipes any manually-added custom redirect rules, TCP listeners, or non-standard configs during reconciliation, even with an AzureIngressProhibitedTargets CRD in place.
26 December 2025
Twenty hours to take a SignalR setup that worked locally in 20 minutes and get it running in an AKS cluster behind an OIDC identity provider — CORS, a 401 on the websocket handshake, and long-polling working while raw websockets still didn't.
21 December 2025
Realizing that everyday exam-prep habits already were prompt engineering: a four-step Azure exam strategy built around priming, format/quantity constraints, and length limits to get sharper, more useful answers out of AI chat tools.
27 November 2025
Three Azure certifications in 2025 — AZ-900, AZ-204, AI-900 — with AI-102 up next.