All posts
Catching Problems Before They Ship — Testing, QA, and Staging
This post explains, without any code, what developers mean by testing, QA, and staging. It unpacks where and how a team filters out problems before sending work to users, at a non-developer's level.
Certified Kubernetes Administrator (CKA) #5 HA Clusters: Multiple Control Planes and an External etcd Cluster
The fifth post in the Certified Kubernetes Administrator (CKA) series. We tackle the high-availability (HA) cluster that removes the single point of failure of a lone control plane. This is a concept-first walkthrough of the trade-offs between the stacked etcd and external etcd topologies, the load balancer in front of the apiservers and --control-plane-endpoint, etcd quorum and fault tolerance, joining control plane nodes, and verifying membership.
Python Automation #2: Excel Automation — Ending Repetitive Reports with openpyxl
Read Excel files with openpyxl, merge per-branch reports from a folder into a single sheet, and finish with header styling and number formats. We also cover the formula and data_only pitfalls, merged cells, and large-file performance.
AWS Certified Solutions Architect - Associate (SAA-C03) #6 Domain 2-1 Resilient Architectures — Multi-AZ , Auto Scaling , ELB
The first post of the SAA-C03 resilience domain. It covers high-availability design using Availability Zones (AZ), the makeup of Auto Scaling groups and their scaling policies (target tracking , step , scheduled , predictive), the three types of ELB (ALB , NLB , GLB) and how to choose between them, the structure that automatically replaces failed instances via health checks, and cross-zone load balancing.
Certified Kubernetes Administrator (CKA) #4 Installing a Cluster with kubeadm: Bootstrapping a Single Control Plane
Part 4 of the Certified Kubernetes Administrator (CKA) series. We stand up a Kubernetes cluster from scratch on a bare Linux machine with kubeadm. From the prerequisites — disabling swap, loading kernel modules, installing containerd — through bootstrapping the control plane with kubeadm init, installing a CNI to bring the node to Ready, and attaching workers with kubeadm join, we walk the whole path command by command.
Python Automation #1: Ending Repetitive Work — First Scripts and File Organizing
Learn the basic shape of an automation script by building a downloads-folder organizer in Python. We sort and move files with pathlib, add a dry-run safety net, and wire up argparse arguments — one full cycle from start to finish.
AWS Certified Solutions Architect - Associate (SAA-C03) #5 Domain 1-4 Secure Architectures — WAF , Shield , Cognito , Secrets Manager
The final post of the SAA-C03 security domain. It covers application-layer protection and credential management: WAF web ACLs and rules (SQLi , XSS , rate , geo), the difference between Shield Standard and Advanced, the role distinction between Cognito User Pool (authentication) and Identity Pool (temporary AWS credentials), and a comparison of Secrets Manager and Parameter Store.
Certified Kubernetes Administrator (CKA) #3 Cluster Architecture 2: Node (kubelet/kube-proxy/CRI), the Pod Networking Model
The third post in the Certified Kubernetes Administrator (CKA) series. Once the control plane makes a decision, the actual containers run on the nodes. We lay out the roles of the three node components — kubelet, kube-proxy, and the container runtime — and the CRI interface, then look from an operations angle at the Kubernetes Pod networking model where every Pod communicates without NAT, and at where the CNI plugin fits in.
Python Testing #7: Running Tests in CI — People Forget, Machines Don't
Build a CI workflow that runs pytest automatically with GitHub Actions. Covers uv caching, a Python version matrix, coverage comments on PRs, pre-commit, and separating slow tests to wrap up the series.
AWS Certified Solutions Architect - Associate (SAA-C03) #4 Domain 1-3 Secure Architectures — VPC Security
The third post of the SAA-C03 security domain. It covers network-boundary security: the difference between security groups and network ACLs (stateful vs. stateless) and how rules are evaluated, the two kinds of VPC Endpoint (Gateway , Interface) and how to choose between them, the structure for exposing a service privately with PrivateLink, bastion hosts and Systems Manager Session Manager, and VPC Flow Logs.
Certified Kubernetes Administrator (CKA) #2 Cluster Architecture 1: Control plane (apiserver/etcd/scheduler/controller-manager)
The second post in the Certified Kubernetes Administrator (CKA) series. We look at how a cluster actually runs, starting from the control plane. We cover what kube-apiserver (the gateway for all communication), etcd (the cluster state store), kube-scheduler (the Pod placement decision), and kube-controller-manager (the reconciliation loop) each do, how the control plane runs as static Pods, and what happens to the cluster when a component dies — all from an operator's point of view.
How Development Teams Work — Agile, Sprints, and MVP
This post explains, without any code, what agile, sprints, and MVP mean. It unpacks why building in short, repeated cycles rather than all at once took hold, at a non-developer's level.