#Certification
167 posts
Red Hat Certified Engineer (RHCE) #7: Jinja2 Templates — Filters, Control Flow, and lookup
The seventh post in the Red Hat Certified Engineer (RHCE) series. We render .j2 files into per-host configuration with the template module, cover Jinja2 syntax for variable output, for, and if, plus filters like default, upper, join, and to_nice_yaml, read files and environment variables with lookup, and even handle whitespace control — all in the form the exam asks for.
Red Hat Certified System Administrator (RHCSA) #4: Boot and the system — systemd, target, GRUB2, password recovery
The fourth post in the Red Hat Certified System Administrator (RHCSA) series. We work through the structure of systemd and how to control services with systemctl, switching the boot target, editing kernel parameters in GRUB2, and the single most frequent RHCSA task — root password recovery with rd.break — by typing the commands ourselves.
AWS Certified Developer - Associate (DVA-C02) #5 Domain 1-4 Development with AWS Services — Messaging and Events
The fourth post of the DVA-C02 development domain. It covers the difference between SQS standard queues and FIFO queues, visibility timeout and long polling, DLQs, SNS pub/sub and fan-out (SNS + SQS), EventBridge's event bus and rule-based routing and schedules, and Step Functions' state machines (Standard vs Express), all at the exam level. Knowing when to choose which messaging service is the core.
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.
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.
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.
AWS Certified Solutions Architect - Associate (SAA-C03) #15 Exam Tips and Frequently Missed Patterns
After finishing SAA-C03 domain study, here is the practical strategy for protecting your score in the exam room. It lays out time management across 130 minutes and Mark for Review, how to filter options by constraint keywords, the elimination strategy, and the concept pairs most often confused on the exam (Multi-AZ vs. read replica, SG vs. NACL, Gateway vs. Interface Endpoint, and more) in a single table.
Certified Kubernetes Administrator (CKA) #13 Scheduling 1: nodeSelector, nodeAffinity, podAffinity/antiAffinity
The thirteenth post in the Certified Kubernetes Administrator (CKA) series. We lay out the four tools that control which node the scheduler places a Pod on. nodeSelector does simple label matching, nodeAffinity expresses node conditions with required and preferred, and podAffinity/podAntiAffinity use topologyKey to place a Pod on the same node as — or a different node from — other Pods. We also look at manual placement that bypasses the scheduler with nodeName.