Are you an experienced Windows system administrator who has just begun to work with CentOS or another Linux server distribution? With the help of the Webmin configuration tool you can perform your new sysadmin duties from a simple web interface.
Most people install WordPress through its web interface using a browser. This is the officially supported installation method, and it's easy and intuitive. But did you know you can also install WordPress from the Linux command line?
An important aspect of administering a CentOS server is to understand its package management system and its various online repositories. Together they ensure you are always running a secure and updated server.
You probably already know that Puppet allows you to set up a server from scratch. You might not realize that Puppet provides efficient, centralized management for complex services such as MySQL.
By default Apache runs all virtual hosts under the same Apache user, with no isolation between them. That makes security vulnerabilities in server-side languages such as PHP a serious threat. An attacker can compromise all websites and virtual hosts on a server as soon as he finds one site that's hosted on it that's vulnerable. To address this problem, you can deploy the Apache module suPHP, which is designed to ensure isolation between virtual hosts that support PHP.
If you develop software, you need a tool to handle bug reporting, requests for changes, and new proposals. Mantis Bug Tracker (MantisBT) is particularly effective at those tasks.
Whether you are a system administrator or a developer, sometimes you need to consider the use of memory in GNU/Linux processes and programs. Memory is a critical resource, and limited memory plus processes that use a lot of RAM can cause a situation where the kernel goes out of memory (OOM). In this state Linux activates an OOM killer kernel process that attempts to recover the system by terminating one or more low-priority processes. Which processes the system kills is unpredictable, so though the OOM killer may keep the server from going down, it can cause problems in the delivery of services that should stay running.
When you update the packages on a badly outdated server, the challenge is to do the upgrades without breaking anything. When dealing with a CentOS installation that's two or three versions behind the current release, a direct upgrade simply isn't the safest option.
Apache ActiveMQ is an open source message server that you can use to send text or binary messages to remote systems with guaranteed delivery, even when there have been network disruptions. I recently wrote about how to develop a simple remote logging application in Java for ActiveMQ, but ActiveMQ also supports languages other than Java via two externally accessible network protocols – OpenWire and STOMP – so you can access and use ActiveMQ from client programs written in such languages as C/C++, .Net, PHP, and Ruby.
Oracle, the company behind MySQL, provides MySQL Utilities, a collection of command-line scripts for accomplishing some common database administration tasks. We put the utilities through their paces on CentOS 6 and MySQL 5.6.