Linux

Limit CPU usage of Linux process

cpulimit is a small program written in C that allows to limit CPU usage by Linux process. Limit is specified in percentage so it’s possible to prevent high CPU load generated by scripts, programs or processes. I found cpulimit pretty useful for the scripts running from cron, for example I …

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Track file changes using auditd

Most of Linux distributions comes with Linux Auditing System that makes it possible to track file changes, file accesses as well as system calls. It’s pretty useful functionality for sysadmins who wish to know who and when accessed and/or changed sensitive files like /etc/passwd, /etc/sudoers or others. Daemon auditd that usually …

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Failover and Load Balancing using HAProxy

HAProxy is open source proxy that can be used to enable high availability and load balancing for web applications. It was designed especially for high load projects so it is very fast and predictable, HAProxy is based on single-process model. In this post I’ll describe sample setup of HAProxy: users’ …

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Linux Restricted Shells: rssh and scponly

Restricted shells like rssh and scponly give sysadmin the possibility to limit the operations that Linux user can do, for example you can create user that will be allowed to copy files via scp but won’t be permitted to login into system’s command line. This is quite important security feature …

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Linux df Command Usage Examples

This post about Linux df command opens series of articles for Linux newbies where you’ll find description and usage examples of major Linux commands like df, top, fsck, mount and so on. Introduction Linux df command can be used to display disk usage statistics for the file systems present on …

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How to Perform Linux Server Monitoring with CloudStats

CloudStats is a powerful tool for Linux server monitoring and network monitoring. This Software-as-a-Service tool allows to track all key indicators of system health, such as CPU and RAM usage, apps and processes performance, network status and much more. The best thing is that CloudStats requires minimum technical skills from …

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Grub Fallback: Boot good kernel if new one crashes

It’s hard to believe but I didn’t know about Grub fallback feature. So every time when I needed to reboot remote server into a new kernel I had to test it on local server to make sure it won’t panic on remote unit. And if kernel panic still happened I …

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Top 5 Password Managers for Linux

In this post you will find set of password managers for Linux which provides secure storage for your passwords for sensitive data. If you still keep the passwords in plain text then you must consider one of available password managers so this article is for you. KeePassX KeePassX has been …

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Geolocation for Nagios

Some time ago I came across NagMap addon for Nagios and found it pretty helpful for monitoring multiple hosts around the world. For example, there are some production servers in Europe, US and others in India and New Zealand and it’s much better see their states on the map rather …

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Why Mosh is better than SSH?

Mosh (stands for Mobile Shell) is replacement of SSH for remote connections to Unix/Linux systems. It brings a few noticeable advantages over well known SSH connections. In brief, it’s faster and more responsive, especially on long delay and/or unreliable links. Key benefits of Mosh Stays connected if your IP is …

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