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AWS Certified Solutions Architect - Associate (SAA-C03) #16 Full-Scale Multiple-Choice Practice Exam — 50 Questions + Explanations
The final post of the SAA-C03 series. Matched to the real exam's domain weights (security 30% , resilience 26% , high performance 24% , cost 20%), you solve 50 questions and find your weak domains through each question's answer and explanation. Solve them on the clock, then go back to the relevant domain post to shore up any gaps.
Certified Kubernetes Administrator (CKA) #14 Scheduling 2: Taints/tolerations, Priority/PriorityClass, preemption
The fourteenth post in the Certified Kubernetes Administrator (CKA) series. We work through taints that let a node push Pods away and tolerations that accept that rejection (the NoSchedule/PreferNoSchedule/NoExecute effects, tolerationSeconds), the default taint on control plane nodes, and finally PriorityClass for ranking priority and preemption that evicts lower-priority Pods when resources run short — all from an operator's point of view with YAML and kubectl.
Certified Kubernetes Application Developer (CKAD) #9 Helm: install, upgrade, rollback, values
The ninth post in the Certified Kubernetes Application Developer (CKAD) series. We organize Helm's chart structure and the release concept that lets you treat a bundle of manifests as a single package, then drill helm repo,install,upgrade,rollback and values overrides hands-on, command by command. We type through the full flow of previewing results with dry-run and reverting with history.
Certified Kubernetes Security Specialist (CKS) #7: seccomp Profiles
The seventh post in the Certified Kubernetes Security Specialist (CKS) series. We cover how to use seccomp to filter the system calls a container can make. We work directly through the three profile types — RuntimeDefault, Localhost, and Unconfined — the securityContext.seccompProfile setting, and writing and verifying a custom profile JSON loaded onto the node.
Kubernetes book now available free in full — Kubernetes: From Basics to EKS in Production
From Pod basics to GitOps, observability, and cost governance on EKS, this 32-chapter Kubernetes book is free to read in full on the site.
Python book now available free in full — Modern Python: From Basics to FastAPI in Production
From variable declarations to FastAPI, SQLAlchemy, JWT auth, and deployment, this 34-chapter, 5-part Python book is free to read in full on the site.
Python Data Analysis #4: Transforming Data — New Columns, Dates, and Missing Values
One post covering the data cleanup phase in pandas: vectorized operations for new columns, the str and dt accessors, what NaN really is, how to decide between dropna and fillna, type conversion with astype, and removing duplicates.
React book now available free in full — React: From Basics to Next.js , TypeScript , Fullstack
From React basics to Next.js, TypeScript, and fullstack, this 35-chapter React book is free to read in full on the site.
Red Hat Certified Engineer (RHCE) #6: Variables and facts — precedence, magic vars, custom facts
The sixth post in the Red Hat Certified Engineer (RHCE) series. From a hands-on angle, we cover where variables are defined (play vars, vars_files, group_vars/host_vars, extra-vars, register) and their reference syntax, the precedence rules where extra-vars always wins, the facts gathered by gather_facts and how to reach them through ansible_facts, how register stores a task result, magic variables like hostvars and groups, and finally custom facts you build under /etc/ansible/facts.d.
Red Hat Certified System Administrator (RHCSA) #3 Shell scripting: conditionals, loops, arguments, exit codes
The third post in the Red Hat Certified System Administrator (RHCSA) series. To write the simple bash scripts that show up regularly on the RHCSA exam, we type our way through shebang and variable quoting, positional arguments and exit codes, test/if/case conditionals and for/while/until loops, command substitution and arithmetic, read input and functions. At the end we write a real-world script that validates arguments and processes multiple targets in a loop.
Why Are There So Many Image File Types? The Basics of JPG, PNG, and Compression
This post explains, without any code, why there are so many image formats, what the compression beneath them is, and which format to choose when. It covers pixels and numbers, lossless and lossy compression, and the differences between JPG, PNG, and WebP, at a non-developer's level.
AWS Certified Developer - Associate (DVA-C02) #4 Domain 1-3 Development with AWS Services — DynamoDB Development
The third post of the DVA-C02 development domain. It covers DynamoDB key design (partition key, sort key), the difference between LSI and GSI, read consistency (eventually consistent vs strongly consistent), capacity modes (on-demand vs provisioned) and throttling, optimistic locking implemented with conditional writes, atomic counters, DynamoDB Streams, TTL, and DAX caching, all at the exam level.