In the previous post on testing Ansible roles with Travis-CI, I introduced a method to run playbooks on CentOS using Docker. In this post, we take this one step further and show how you can run multi-platform tests of Ansible roles.Read on →
In this first post on testing Ansible roles with Travis-CI, we’ll discuss how you can apply a test playbook on CentOS. Out-of-the-box, Travis-CI doesn’t support CentOS, as its test environment is Ubuntu-based. However, Travis-CI allows you to set up a Docker container and this opens up all kinds of possibilities.Read on →
Many HOWTO’s and blog posts about installing MySQL/MariaDB, a LAMP stack, etc. suggest to run the script
mysql_secure_installation to tighten the security holes in the default installation of the database engine. This includes setting a root password (empty by default), removing anonymous users, and deleting a test database. For a database server that you’re going to run in production, it is really important to do this. However, I have a problem with the fact that
mysql_secure_installation is interactive, i.e. it asks for user input. This makes it very hard to include it in an automated setup. In this post, we’ll discuss how the script works and how we can automate what it does.
When you execute the command
ls -l in UNIX, you get detailed information about files: permissions, file size, date of last modification, etc. A while ago, I got a question from one of my students who wondered what the second column meant. According to the documentation, it’s the “number of hard links,” but what does that actually mean? Let’s get to the bottom of this.
VirtualBox Guest additions are a set of drivers that you can install on virtual machines to enable a few cool features: a scaling desktop in the VM, shared clipboard, shared folders, etc. This post discusses how to install these in Fedora 22.Read on →
Hyper-V and VirtualBox are two virtualization platforms that we both use in our system administration courses. Unfortunately, once Hyper-V is active, it won’t coexist with other virtualization platforms. In this post, I discuss a method to work around this problem by setting up a custom boot entry for each platform.Read on →
Writing Vagrantfiles is tedious, especially when you’re setting up a multi-VM environment. Typically, people will copy/paste code blocks that define hosts, but that becomes unwieldy. However, a Vagrantfile is “just” Ruby, so can’t we simplify things a bit using the power of the language? Turns out, we can! Read below to find how you can reduce setting up a multi-VM Vagrant environment to writing a simple YAML file.Read on →
One of the greatest pitfalls when working with VirtualBox VMs is a good understanding of how networking works. In this post, we’ll discuss the most important differences between them, and their limitations when you use VirtualBox to experiment with setting up network services on a VM.
In our system administration courses, we use VirtualBox to allow students to set up their own Linux machines without having to resort to dual booting. VirtualBox is certainly not the “best” virtualization platform, but it is supported on the three common desktop platforms and works similarly on all of them.Read on →