DevOps

Linux / 01 Sep 2026 / 6 min read

Troubleshooting systemd Services with systemctl and journalctl

When a Linux service fails under systemd, the fastest path to a fix is usually not restarting it repeatedly. A better approach is to inspect the service state, read the relevant logs, confirm the effective unit configuration, and validate changes before trying again. This guide presents a repeatable troubleshooting workflow for modern Linux distributions that use systemd. The examples use commands available in systemd 257, but the core workflow also applies to many earlier systemd releases.

Linux systemd

Web Development / 01 Sep 2026 / 6 min read

Liveness and Readiness Health Checks for Backend Services

Health endpoints look simple, but their semantics directly affect how a production platform routes traffic and restarts applications. A poorly designed check can turn a temporary database slowdown into a restart loop or send requests to an instance that has not finished initializing. The most useful model separates two questions: Liveness: Is this process still capable of running? Readiness: Should this instance receive new traffic right now? Those questions sound similar, but they should usually have different answers and different failure behavior.

Backend Reliability

Cloud Computing / 01 Sep 2026 / 5 min read

Designing Stateless Web Services for Horizontal Scaling

Horizontal scaling adds application replicas instead of making one machine larger. The load balancer can send each request to any healthy instance, which only works reliably when instances do not depend on unique local state. “Stateless” does not mean the application has no state. It means durable or shared state lives outside an individual process so any replica can continue serving the workload. Identify hidden local state A service may appear stateless while depending on:

Cloud Computing DevOps

Cloud Computing / 01 Sep 2026 / 5 min read

Blue-Green Deployments for Safer Zero-Downtime Releases

A blue-green deployment keeps two production-capable application environments. One serves live traffic while the other receives the new release. After validation, traffic is switched to the candidate environment. The pattern can make rollback fast, but it does not automatically make a release safe. Database changes, background jobs, caches, and external side effects can still make an old version incompatible with the new state. The basic release sequence Assume blue is currently live and green will run the new version.

DevOps Deployment

Cloud Computing / 06 Sep 2025 / 3 min read

Reverse Proxy with Nginx and Go for Microservices

As an application grows, splitting it into smaller services can make independent deployment and scaling easier. For example: Product service on port 8080 Blog service on port 8081 Users should not need to know those internal ports. An Nginx reverse proxy can expose both services under one domain and route requests by URL path. 1. Configure the Nginx Reverse Proxy Create a site configuration: sudo nano /etc/nginx/sites-available/yourdomain.com Add:

DevOps Nginx

Cybersecurity / Updated 10 Sep 2025 / 2 min read

How to Whitelist IP Address Ranges with .htaccess

.htaccess is useful for more than URL rewriting and caching. It can also provide an additional access-control layer, including restricting an application to specific IP addresses or IP ranges. This technique can be useful when: An application is still in development and should only be available to an internal team. You want to protect sensitive paths such as /admin or /api. A server should only be reachable from an office network or VPN. Whitelist One IP Address To allow only one IP address:

DevOps Security

Cybersecurity / Updated 10 Sep 2025 / 2 min read

How to Block IP Ranges with `.htaccess`

One useful feature of Apache is the flexibility of .htaccess. In addition to URL rewriting and caching rules, .htaccess can also restrict access based on IP addresses. If you are dealing with spam bots, brute-force attempts, or unwanted traffic from a particular network, one quick option is to block an individual IP address or an entire range. Block a Single IP Address To block one IP address, use: <RequireAll> Require all granted Require not ip 192.168.1.100 </RequireAll> This blocks 192.168.1.100 while allowing other clients to access the site.

DevOps Apache

Cybersecurity / 03 Sep 2025 / 2 min read

Creating a CA Bundle and Converting an SSL Certificate to .PFX

Managing SSL/TLS certificates is a routine task for many developers and system administrators. One common requirement is to combine intermediate certificates into a CA bundle and then convert the certificate and private key into a .pfx file. The .pfx format, also known as PKCS#12, is commonly used when importing certificates into Windows Server and IIS, Microsoft Exchange, and other applications that expect a PKCS#12 bundle. This guide walks through the process.

DevOps SSL

Cybersecurity / 03 Sep 2025 / 3 min read

.htaccess Rules to Prevent PHP Execution

Public upload directories are a common security-sensitive part of web applications. If an attacker manages to upload a file such as shell.php and the web server executes it, the upload feature can become a route to remote code execution. On Apache, a directory-specific .htaccess configuration can help prevent script execution in locations that should contain only static files. Why .htaccess Can Help Apache supports .htaccess files for directory-level configuration when the server permits the relevant overrides. This makes it possible to apply security rules to a specific directory without changing every virtual-host setting.

DevOps Security

Cloud Computing / Updated 02 Sep 2025 / 2 min read

Using Nginx as a Reverse Proxy for a Go Application

A Go web application often listens directly on an application port such as :8080. If you want users to access it through a normal domain on port 80 or 443, you can place Nginx in front of it as a reverse proxy. Using Nginx in front of a Go service provides several benefits: Client requests reach Nginx before being forwarded to the Go application. TLS termination can be handled at the proxy layer. Multiple application instances can be load balanced. Static assets can be served separately when that architecture makes sense. This guide shows a basic setup.

DevOps Golang