Protecting the Root Filesystem on Ubuntu with Overlayroot

In certain situations, it is desirable to have a read-only root filesystem. This prevents any changes from occurring on the root filesystem that may alter system behavior, and it allows a simple reboot to restore a system to its pristine state. Examples of such applications include kiosks and embedded devices. Using overlayroot on Ubuntu makes […]

Debian and Ubuntu Automatic Security Updates

Security patches for libraries and tools come out quite frequently. Just subscribe to any Linux distribution security list, and you’ll find that security updates are released with astounding frequency, sometimes even daily. Even kernel security updates are fairly common, with two security patches being released for the kernel used by Ubuntu 12.04 LTS in June. […]

5 Linux Filesystem Utilities for Diagnostics

A great deal of the time, I work on the command line — usually logged into a remote system, doing some tasks or troubleshooting some problem. Quite often, this involves checking or manipulating something on the filesystem. There are dozens of filesystem utilities. Most are well-known file manipulation utilities such as mv, rm, touch, mkdir, […]

Hosting Provider ‘Upgrade’ Changes Stolen CPU

Recently, a hosting provider’s ‘upgrade’ dramatically changed the stolen CPU time on one of our systems. I investigated and found that our virtual machine’s CPU allocation had been deprioritized. The rest of the post describes “stolen CPU” and the behavior that we experienced on our virtual machine. Anyone who runs operating systems (especially UNIX or […]