Practical notes on Kubernetes, cloud infrastructure, cybersecurity, networking, DevOps, and machine learning.https://www.gulcantopcu.com/https://www.gulcantopcu.com/posts/what-os-cpu-count-gets-wrong-kubernetes-cpu-limited-pod/https://www.gulcantopcu.com/posts/what-os-cpu-count-gets-wrong-kubernetes-cpu-limited-pod/A hands-on Minikube lab showing why `os.cpu_count()` returns the node's full CPU count inside a CPU-limited pod, and what happens when Gunicorn sizes workers from that number instead of the cgroup quota.Wed, 24 Jun 2026 00:00:00 GMThttps://www.gulcantopcu.com/posts/kubernetes-gpu-device-plugin-allocation/https://www.gulcantopcu.com/posts/kubernetes-gpu-device-plugin-allocation/What actually happens when you request nvidia.com/gpu: 1? A step-by-step trace through the scheduler, kubelet device manager, gRPC allocation on nvidia-gpu.sock, and container injection, on a real minikube cluster with an RTX 3050.Sat, 21 Mar 2026 00:00:00 GMThttps://www.gulcantopcu.com/posts/kubernetes-cross-node-networking-kindnet/https://www.gulcantopcu.com/posts/kubernetes-cross-node-networking-kindnet/Learn how pods communicate across nodes in Kubernetes with Kindnet using plain L3 routing, without overlays or tunnels.Fri, 02 Jan 2026 00:00:00 GMThttps://www.gulcantopcu.com/posts/sql-injection-detection-sigma-kubernetes/https://www.gulcantopcu.com/posts/sql-injection-detection-sigma-kubernetes/Scale your detection logic with Sigma rules that work across multiple SIEM platforms. Convert lab-tested SQL injection detection into portable, version-controlled rules.Mon, 13 Oct 2025 00:00:00 GMThttps://www.gulcantopcu.com/posts/soc-detection-lab-kubernetes/https://www.gulcantopcu.com/posts/soc-detection-lab-kubernetes/Deploy OWASP Juice Shop on Kubernetes and build a complete detection pipeline with Falco for syscall monitoring, Zeek for network analysis, and Loki/Grafana for centralized observability.Thu, 25 Sep 2025 00:00:00 GMThttps://www.gulcantopcu.com/posts/sql-injection-practical-guide/https://www.gulcantopcu.com/posts/sql-injection-practical-guide/Learn SQL injection from the ground up with a hands-on Docker lab. Build a vulnerable PHP-MySQL application and execute real attacks including authentication bypass, UNION-based data extraction, error-based leaks, and time-based blind enumeration.Tue, 09 Sep 2025 00:00:00 GMThttps://www.gulcantopcu.com/posts/pod-birth-veth-pairs-ipam/https://www.gulcantopcu.com/posts/pod-birth-veth-pairs-ipam/Understand the complete lifecycle of pod creation in Kubernetes, from veth pair creation to IP address allocation and network setup.Sun, 17 Aug 2025 00:00:00 GMThttps://www.gulcantopcu.com/posts/intra-node-pod-traffic/https://www.gulcantopcu.com/posts/intra-node-pod-traffic/Deep dive into how pods on the same node communicate in Kubernetes using Kindnet. Understand veth pairs, bridge networking, and packet flow.Fri, 01 Aug 2025 00:00:00 GMThttps://www.gulcantopcu.com/posts/kubernetes-zero-downtime-deployments/https://www.gulcantopcu.com/posts/kubernetes-zero-downtime-deployments/Downtime is a nightmare for businesses. This guide explores advanced deployment strategies like Blue/Green and Canary deployments to achieve seamless Kubernetes deployments.Sun, 06 Jul 2025 00:00:00 GMThttps://www.gulcantopcu.com/posts/mlops-kubeflow-kserve-churn-prediction/https://www.gulcantopcu.com/posts/mlops-kubeflow-kserve-churn-prediction/This guide shows you how to effectively use Kubeflow, KServe, and Flask to predict customer churn and revolutionize your MLOps pipeline.Thu, 03 Jul 2025 00:00:00 GMThttps://www.gulcantopcu.com/posts/kubernetes-configmap-atomic-updates/https://www.gulcantopcu.com/posts/kubernetes-configmap-atomic-updates/Understand how Kubernetes uses symlinks and kubelet to atomically update ConfigMaps mounted as volumes without pod restarts.Fri, 20 Jun 2025 00:00:00 GMThttps://www.gulcantopcu.com/posts/canary-deployments-cicd-gitops/https://www.gulcantopcu.com/posts/canary-deployments-cicd-gitops/Traditional software deployment methods are full of problems. This article explores how a well-structured CI/CD pipeline powered by Argo Rollouts, GitHub Actions, and Kubernetes can revolutionize your DevOps practices.Sat, 15 Feb 2025 00:00:00 GMThttps://www.gulcantopcu.com/posts/kubernetes-the-hard-way-wsl/https://www.gulcantopcu.com/posts/kubernetes-the-hard-way-wsl/For those who crave a deep understanding of how Kubernetes really works, Kubernetes The Hard Way offers a hands-on approach to setting up a Kubernetes cluster from scratch.Wed, 01 Jan 2025 00:00:00 GMT