All posts
Certified Kubernetes Security Specialist (CKS) #12 Pod-to-Pod mTLS: Cilium
The twelfth post of the Certified Kubernetes Security Specialist (CKS) series. As the final topic of the Minimize Microservice Vulnerabilities domain, it covers the problem that Pod-to-Pod traffic is plaintext by default and the need for encryption in transit. We organize, concept-first, the sidecar mTLS model of Service Mesh (Istio/Linkerd), Cilium's transparent encryption (WireGuard/IPsec) and its mTLS direction, the difference between NetworkPolicy (L3/L4) and mTLS (encryption/identity), and why in-transit encryption matters from a CKS perspective.
How Are Online Payments Processed? Payment Gateways, Authorization, and Settlement Made Simple
This post explains, without any code, what happens in the few seconds after you press the pay button in online shopping. It covers what a payment gateway does, the difference between authorization and settlement, and who actually holds your card information, all at a non-developer's level.
How Does "Sign in with Google" Work? OAuth Made Simple
This post explains, without any code, whether a service learns your password when you log in with Google, and how social login works. It covers the principle of not handing over your password, OAuth and the consent screen, and the information received via a token, at a non-developer's level.
Kubernetes and Cloud Native Associate (KCNA) #3: Kubernetes Fundamentals 2 — API, Containers, Scheduling
A rundown of the Kubernetes API object model (apiVersion, kind, metadata, spec, status) and the declarative vs. imperative styles, container images and runtimes, the kube-scheduler scheduling process (nodeSelector, affinity, taint), and how to inject configuration with ConfigMap and Secret. This wraps up the back half of Domain 1, Kubernetes Fundamentals (46%).
Python's JIT Compiler: From the 3.13 Experiment to Realistic Expectations
A look at the experimental copy-and-patch JIT compiler that landed in CPython 3.13. How it works, how to enable it, what changed in 3.14, and what you can realistically expect from it today.
Red Hat Certified Engineer (RHCE) #11: Writing and Using Roles
Part 11 of the Red Hat Certified Engineer (RHCE) series. We cover the standard role directory structure and ansible-galaxy role init, the difference between the roles key and include_role/import_role, why defaults sits at the lowest role variable precedence, and the dependencies in meta/main.yml plus roles_path. We practice the exam-favorite flow of writing a role and calling it from a playbook with worked examples.
Red Hat Certified System Administrator (RHCSA) #8 Packages and repositories: dnf, modules, AppStream
The eighth post in the Red Hat Certified System Administrator (RHCSA) series. We cover installing, removing, and searching packages with dnf, adding repositories, and working with AppStream module streams and profiles. From RHCSA staples like adding a specific repository and installing from it, all the way to switching module streams — all walked through with command examples.
AWS Certified CloudOps Engineer - Associate (SOA-C03) #3 Domain 1-2 Monitoring — CloudWatch Logs, Logs Insights, Agent
The third post in the SOA-C03 series covers the log side of CloudWatch. It covers the structure of log groups and log streams, retention periods and cost, how to collect logs and OS metrics with the CloudWatch Agent, metric filters that extract metrics from logs, Logs Insights queries, and subscription filters that deliver logs in real time.
AWS Certified Developer - Associate (DVA-C02) #9 Domain 3-1 Deployment — CI/CD
The first post of the DVA-C02 deployment domain. It covers the division of roles among the AWS developer tools (CodeCommit,CodeBuild,CodeDeploy,CodePipeline,CodeArtifact), along with CodeBuild's buildspec.yml phases and environment variables, CodeDeploy's appspec.yml with deployment groups and lifecycle hooks, and CodePipeline's stage composition and artifact flow at the exam level. The key is knowing which tool does what.
Build an Online Shop with Next.js #4: Checkout and Payment Simulation
Create orders with Server Actions and simulate success/failure with a fake payment gateway. We also cover practical patterns for handling form state with useActionState and useFormStatus.
Certified Kubernetes Administrator (CKA) #18 Networking 1: Service (ClusterIP/NodePort/LoadBalancer/ExternalName)
Part 18 of the Certified Kubernetes Administrator (CKA) series. We follow the flow where a Service uses a selector to pick Pods, builds Endpoints, and kube-proxy turns those into node-level rules. We cover the four types — ClusterIP, NodePort, LoadBalancer, ExternalName — the distinction between port/targetPort/nodePort, headless Services, k expose, and the operational instinct for tracing the cause through Endpoints when a Service stops working.
Certified Kubernetes Application Developer (CKAD) #13 ConfigMap and Secret in Depth: volume vs env, Auto-Refresh
The thirteenth post in the Certified Kubernetes Application Developer (CKAD) series. We create ConfigMaps and Secrets that pull configuration and sensitive data out of code, and cover the three ways to inject them — env (valueFrom , envFrom) and volume mounts — in exam-task format. In particular, we drill the difference that env stays fixed until the Pod restarts while a volume auto-refreshes after a delay.