Author name: CrtMgr Team

User management is basic Linux administration in the same way plumbing is basic house maintenance: you can ignore it right up until the day it leaks into everything else. Bad user and group hygiene creates permission problems, weak sudo rules, confusing service ownership, and messy offboarding. Good hygiene is not glamorous, but it prevents a […]

sysctl is one of those Linux tools that attracts two kinds of bad advice. One camp never touches it and leaves obvious workload mismatches unaddressed. The other pastes giant “performance tuning” blocks from random forum posts into /etc/sysctl.conf, reboots, and hopes for free speed. I do not recommend either approach. Kernel parameters absolutely matter, but

When a service “is down,” the network is usually blamed first and understood last. I have seen people restart perfectly healthy daemons because they never checked whether the port was listening, whether a firewall was dropping the traffic, or whether the client was even talking to the right IP. Good network troubleshooting is less about

Memory problems on Linux rarely start with the machine being literally out of RAM. They usually start with someone looking at free -h, seeing almost all memory marked as used, and assuming the kernel is leaking, the database is bloated, or swap is somehow the root of every evil. I have seen good servers rebooted

Disk I/O problems are some of the easiest Linux performance issues to misread. CPU looks fine, memory is not completely exhausted, load average is high, and the server still feels sticky. Commands hang for a second or two. Databases stutter. Backups start slowly and then drag everything else with them. That is usually when I

Rate limiting is one of those things that’s easy to get wrong in both directions — too loose and it does nothing, too tight and you start blocking real users. I’ve tuned rate limiting configs on production sites a few times and I’ve made both mistakes. Here’s what I’ve learned about how Nginx rate limiting

Sometimes you need to protect a URL quickly — a staging environment, an admin panel, a Prometheus metrics endpoint, internal documentation. Setting up a full authentication system is overkill. Nginx’s built-in basic authentication handles these cases well. Basic auth has a reputation for being insecure, but that reputation is mostly from HTTP days. Over HTTPS,

A default MySQL or MariaDB installation is conservative — configured to work on minimal hardware. Most production servers have significantly more RAM and CPU than the defaults assume, which means the database is leaving performance on the table. These are the settings I tune when setting up a database server. Not all of them apply

Running a Node.js app directly on port 80 or 443 is possible but not how I’d do it in production. Nginx in front of Node.js gives you SSL termination, static file serving, caching, compression, rate limiting, and request buffering — things Node.js can do but doesn’t do as efficiently as a dedicated web server. Here’s

SSH is more than a remote shell. The tunneling capabilities — local forwarding, remote forwarding, and dynamic SOCKS proxying — are genuinely useful for accessing services that aren’t directly reachable, and I reach for them regularly. Local Port Forwarding Local forwarding creates a tunnel: you connect to a local port, and SSH forwards the connection