servers

Remote Command Execution with SaltStack

A few weeks back I wrote an article Getting started with SaltStack; that article covered Configuration and Package Automation with Saltstack. In Today's article I am going to cover SaltStack's Remote Execution abilities, a feature that I feel Saltstack has implemented better than other automation tools. Running a command in a State If you remember from the previous article SaltStack's states are permanent configurations. Adding a command in a Salt state is used when you want to have a command that is run after provisioning a server, run every time Salt manages the state of the system or run when certain conditions are true.

Understanding a little more about /etc/profile and /etc/bashrc

Recently I was working on an issue where an application was not retaining the umask setting set in the root users profile or /etc/profile. After looking into the issue a bit it seemed that the application in question only applied the umask setting that was set in /etc/bashrc and would not even accept the values being the applications own start scripts. After doing a bit of researched I learned a little bit more about what exactly these files do, the differences between them and when they are executed.

Adding simulated network latency to your Linux server

Have you ever said to yourself, “man I really need to slow down my internet”? Probably not very often, but recently I found myself in a dilemma where I needed to simulate 120ms of network latency in my test environment which consists of servers that are racked right next to each other. That is where the command tc comes in. Within the current distributions of Linux there is a kernel component called netem, which adds Network Emulation and is used for testing and simulating the same types of issues one would see in a WAN (Wide Area Network).