Howto


Ansible WordPress Howto – Part 3

In previous posts in this series we discussed the basics for installing the main components of a highly available WordPress application, the application is deployed on a 3-tier infrastructure:     In the last post I installed the the main tools that will be used on the three tiers, so for load balancers I used […]


howto use ansible to setup a node.js gaming application 1

As IT systems become more complex and the need for better solutions to manage hundreds and thousands of services and applications increases, administrators have realized that using traditional operational methods to manage scalable systems are not working any more. Tools for configuration management and automation become essential. Such tools can be used to install a […]


rsync remote port

If you are running ssh on a non standard port you can still use rsync over ssh with the following syntax. rsync is a powerful tool to create simple backup and deployment workflows. Here are some examples with common rsync use cases … Copy files from remote to local The options “-av” are the most […]


python yum check-update howto

If you are running an rpm based Linux system like CentOS you might want to automatically and regularly check if security-updates are available. You can use existing commandline tools or python scripts. This article is about checking if linux host is up-to-date with python yum module – without scraping the cli tool. The yum commandline […]


python call constructor of parent class

python call super constructor

If you want to call the constructor of a parent class you have a couple of options. For example: In this first example we are talking about “new-style” classes. Basically these are classes that inherit from “object” ( class Parent(object) ). In this case you can call the super() method with a reference to Child […]


sed delete line

In this article I want to explain how you can use sed to automatically delete a line from a file or a stream. This can be useful in the following cases: delete the first line of a file to implement a simple resource pool (e.g. available IP addresses can be managed in a simple text […]


sed replace newline (or 5 ways to remove line breaks with sed, python, tr, perl, xargs) 1

When you are automating tasks you often come to the point where you have to remove newlines / line breaks from documents or ASCII streams to use this output as parameters for the next steps. There are many options how this can be done. Especially in Big Data streaming you should also consider the performance […]

sed remove line break vs replace newline with other tools