Linux - Let's Encrypt for Java Apps
Intro Install certbot as mentioned in my previous post on Linux - Install Certbot. By default, certbot retrieves a certificate and installs it immediately on the web server by adding an extra par...
Harry Vasanth
DevOps - Grafana: Implementing Dynamic 'Multi-Variable' Dashboards for Fleet Management
The Problem: Dashboard Sprawl You have 10 different clusters, each with 50 nodes. If you create a static dashboard for every host, you end up with 500 dashboards. When you want to add a new “Disk ...
Linux - Disk Quotas: Solving 'Mountpoint not found' and systemd Race Conditions
The Problem: The Zombie Quota You’ve added usrquota,grpquota to your /etc/fstab. You’ve remounted the filesystem. But when you run quotacheck -avug, you get: quotacheck: Cannot find filesystem to ...
Proxmox - LXC AppArmor: Resolving 'Permission Denied' on Mounts and Nesting
The Issue: The Root User who isn’t Root You’re running an LXC container on Proxmox. You try to mount an NFS share, start a Docker daemon inside the container, or even just run systemd-timesyncd, a...
Networking - iperf3: Advanced Throughput Testing and BDP Calculations
The Problem: The 10Gbps Link that only does 2Gbps You’ve just installed a shiny 10Gbps fibre link between two datacenters. You run iperf3 -c <remote_ip> and see a disappointing 2.1 Gbps. You...
Docker - Traefik: Resolving 'Client IP' pass-through in NAT and Proxy Environments
The Problem: IP Address Obfuscation You’ve set up Traefik as a reverse proxy for your Docker containers. However, in your application logs (Nginx, Go, PHP), every visitor appears to be coming from...
Linux - Systemd Overrides: The Professional Way to Modify Package-Managed Services
The Problem: The Overwrite Trap You need to change a service’s environment variables or its OOM score. You edit /lib/systemd/system/nginx.service directly. A month later, apt upgrade runs, a new N...
DevOps - Prometheus: Proactive SSL Monitoring with Blackbox Exporter
The Invisible Failure: Expired Certificates Every well-versed admin has a horror story about a production outage caused by a forgotten SSL certificate. Modern infrastructure has hundreds of certif...
Networking - Linux Bridges: Eliminating the 30-Second 'Silence' with STP Tuning
The Problem: The Missing Cloud-init Data You’ve automated your VM deployments, but you notice a strange issue: the VMs boot, but they fail to fetch their configuration from the network. If you wai...
Proxmox - Automation: Bulletproof VM Templates with Cloud-init and Terraform
The Goal: 60-Second Server Provisioning Manually installing an OS from an ISO is a waste of a well-versed admin’s time. We want a workflow where we can run terraform apply and have a fully configu...