Ansible exists to help automate the time consuming repeated tasks that technologist depend upon. One very common jobs is to create and tear down a virtual machine. While cloud technologies have made this possible to perform remotely, there are many times when I’ve needed to setup and tear down virtual machines on systems that were stand alone Linux servers. In this case, the main interfaces to the machine are ssh and libvirt. I recently worked through an Ansible role to setup and tear down an virtual machine via libvirt, and I’d like to walk through it, and record my reasons for some of the decisions I made.
Lets say you are an administrator of an OpenStack cloud. This means you are pretty much all powerful in the deployment. Now, you need to perform some operation, but you don’t want to give it full admin privileges? Why? well, do you work as root on your Linux box? I hope note. Here’s how to set up a self trust for a reduced set of roles on your token.
My laptop is my Demo machine. I need to be able to run the Red Hat cloud Suite of software on it. I want to install this software the same way a customer would. However, much of this software is server side software, and my machine was registered as a workstation. This means the Red Hat Content network won’t show me the server yum repositories. Here is how I converted my machine to be a server.
If I want to run software collections code without enabling bash and running interactively, I have to pass the whole command on the command line like this:
scl enable rh-maven35 "mvn package"
I’ll need to use this form to run from Ansible.
I’ve been interested in the intersection of Ansible and Java development. To test this out, I want to build a “Hello World” maven App and use Ansible to drive the process to build, test, and deploy it. I’m going to use the Software Collections way of installing and running Maven to build a simple Tomcat Web Application as the basis.
Now that we can use the REST API to list inventory, it is not a big stretch to decide we want to kick off Jobs, too. Here it is in a nutshell, and some related operations for working with jobs and templates.
In an earlier post, I wrote about using the OpenStack Ansible inventory helper when calling and Ansible command line tools. However, When developing an playbook, often there is more information pulled from the inventory than just the set of hosts. Often, the inventory also collects variables that are used in common across multiple playbooks. For this reason, and many more, I want to be able to call an Ansible playbook or Ad-Hoc command from the command line, but use the inventory as defined by an Ansible Tower instance. It turns out this is fairly simple to do, using the REST API.
While Tower makes it easy to manage custom inventory, I still want to develop using the command line. Thus, I want to generate a comparable smart inventory for my Ansible playbook as I get from tower.