Ranjith R
Linux SysAdmin & Cloud Engineer
About the Author
Ranjith R is a Linux System Administrator and Cloud Engineer who manages 400+ production domains across shared hosting, VPS, and cloud infrastructure. His work spans server hardening, DNS and email deliverability, CI/CD pipelines, and incident response — the kind of day-to-day operational depth that most tutorials skip.
Every article on this site is written from that operational experience: real commands run against real servers, troubleshooting steps that came from an actual outage, and production tips that only show up after something has broken in front of you at least once.
He is RHCSA-certified (Red Hat Certified System Administrator) and focuses on AWS Cloud and DevOps automation alongside his day-to-day Linux administration work.
Credentials
All Articles
Linux File Permissions, Ownership & umask Explained
The rwx permission model, chmod symbolic vs. octal notation, chown/chgrp, setuid/setgid/sticky bits, and how umask sets your defaults.
Cron & systemd Timers: Scheduling Jobs in Linux
Crontab syntax, special strings, run-parts directories, and modern systemd timer units — with a direct comparison of when to use each.
SSH Hardening: Key-Based Auth, Fail2ban & Bastion Hosts
Disabling password auth, key-based login, sshd_config hardening, fail2ban jails, and bastion-host architecture for production access.
LVM: Logical Volume Management from Scratch
Physical volumes, volume groups, and logical volumes — creating, extending, and shrinking storage without unmounting production filesystems.
AWS IAM Fundamentals: Users, Roles, Policies & Least Privilege
Users vs. roles vs. groups, identity-based vs. resource-based policies, policy evaluation logic, and applying least privilege in practice.
EC2 Instance Types & Purchasing Options
Instance family naming (m6i, c7g, r6g), On-Demand vs. Reserved vs. Spot vs. Savings Plans, and picking the right combination for a real workload.
S3 Storage Classes & Lifecycle Policies
Standard, Intelligent-Tiering, Glacier and Deep Archive compared on cost/retrieval time, plus lifecycle rules that move and expire objects automatically.
VPC Networking: Subnets, Route Tables & Security Groups
CIDR planning, public vs. private subnets, route tables, internet/NAT gateways, security groups vs. NACLs, and a reference 2-tier VPC design.
Git Branching Strategies: Git Flow vs. Trunk-Based Development
Git Flow's branch model compared against trunk-based development with short-lived feature branches and feature flags — with a decision framework.
Docker Compose for Multi-Container Applications
compose.yaml services, networks, volumes, environment files, healthchecks, and dependency ordering for a real app + database + cache stack.
Kubernetes Pods, Deployments & Services Explained
The Pod as the atomic unit, Deployments for replica management and rollouts, and Services (ClusterIP/NodePort/LoadBalancer) for stable networking.
Terraform State Management & Remote Backends
Why state exists, the danger of local state on a team, S3 + DynamoDB remote backends with state locking, and recovering from state drift.
How ATS Resume Screening Actually Works
What an Applicant Tracking System parses, why tables/columns/images break parsing, keyword matching mechanics, and how to format around it.
DevOps Resume: Structure, Keywords & Examples
Section order for a DevOps/SRE resume, which tools and metrics recruiters scan for first, and a before/after bullet-point rewrite.
Wazuh: SIEM Architecture, Agents & Detection Rules
Wazuh manager/indexer/dashboard architecture, agent deployment, custom detection rules, alert tuning, and the operational dashboard workflow.
OWASP Top 10: Vulnerabilities, Exploits & Fixes
SQL injection, XSS, CSRF, RCE, and the rest of the OWASP Top 10 — with vulnerable/fixed code examples and the security headers that stop them.
Bitbucket: Repositories, Pipelines & Deployments
Repository setup, Bitbucket Pipelines YAML, branching permissions, pull requests, and deployment stages to servers and cloud targets.
Nagios Monitoring: NRPE, Checks & Alerting
Nagios Core installation, NRPE agent setup, host and service checks, notification/escalation rules, and the commands you'll run daily.
Ansible Automation: Inventory, Playbooks & Roles
Inventory files, playbooks, variables, roles, handlers, Ansible Vault, and real-world playbooks for hardening and deploying servers at scale.
Jenkins CI/CD: Pipelines, Agents & Deployments
Installation, declarative pipelines, agents, credentials, GitHub/Bitbucket webhooks, deployment stages, and pipeline troubleshooting.
SonarQube: Quality Gates & CI Integration
Installation, quality profiles, quality gates, scanner configuration for multiple languages, and wiring SonarQube into a CI/CD pipeline.
AWS for DevOps: IAM, EC2, VPC, S3 & Deployment Patterns
IAM, EC2, S3, Route53, CloudFront, ACM, RDS, CloudWatch, VPC, ALB, and Security Groups — with real deployment architectures and interview questions.
Docker in Production: Images, Volumes, Networks & Compose
Containers, images, volumes, networks, Dockerfiles, Compose stacks, private registries, and the troubleshooting playbook for production containers.
Cloudflare: DNS, SSL, Caching, WAF & Tunnels
DNS management, SSL/TLS modes, caching rules, firewall, WAF, rate limiting, page rules, origin certificates, and Cloudflare Tunnel.
Git Mastery: Branching, Rebasing & GitHub Workflows
Git internals, branching, merging, rebasing, cherry-picking, stashing, resetting, reverting, tagging, Git Flow, and resolving merge conflicts for real.
Linux Administration: The Complete Field Guide
Filesystem hierarchy, permissions, users & groups, systemd, journald, cron, networking, SSH hardening, disk management, LVM, and RHCSA exam tips.
cPanel & WHM: Accounts, Email, DNS & Troubleshooting
Account management, email configuration, backups, SSL, DNS zones, PHP versions, and MySQL administration through cPanel/WHM.