Managing DNS locally with /etc/hosts

Before the advent of a distributed domain name system; networked computers used local files to map hostnames to IP addresses. On Unix systems this file was named /etc/hosts or “the hosts file”. In those days, networks were small and managing a file with a handful of hosts was easy. However as the networks grew so did the methods of mapping hostnames and IP addresses. In modern days with the internet totaling at somewhere around 246 million domain names (as of 2012) the hosts file has been replaced with a more scalable distributed DNS service....

 · 6 min · Benjamin Cane

Install RackTables and start tracking your IP address inventory

Recently while I was scouring through a spreadsheet of “unallocated” IP addresses, I thought to myself. There has to be a better way to manage an inventory of IP addresses, and while I'm at it maybe even provide a list of provisioned servers. After some googling I found myself on RackTables.org the home of an open source project that aims to provide just what I was looking for. An Inventory system that tracks and manages Servers, Racks, IP Addresses and just about everything else in a data center....

 · 6 min · Benjamin Cane

Symlinks vs Hardlinks and how to create them

In a previous article I covered a little bit about Symlinks and Hardlinks but I never really explained what they are or how to create them. Today I am going to cover how to create both Symlinks and Hardlinks and what the difference is between the two. What are Symlinks and Hardlinks Hard Links In Linux when you perform an listing in a directory the listing is actually is a list of references that map to an inode....

 · 7 min · Benjamin Cane

Changing the default nice value for a user or group

Recently I coveredhow to increase and decrease the CPU priority of processes using nice and renice. Today I am going to cover how to change the default niceness value for a user or group. Why change the default CPU priority value? Before explaining how to change the default niceness value, let's cover why this could be useful. Scenario #1 You have a system that has thousands of users that log in via SSH and could potentially run CPU intensive tasks....

 · 2 min · Benjamin Cane

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....

 · 6 min · Benjamin Cane