Installing Ansible AWX on CentOS 8

AWX is a web application that sits on top of Ansible, providing a “user interface, REST API and task engine for Ansible”. Since AWX can integrate into vRealize Automation, I decided to stand up an instance of it in my home lab.

Installing Ansible

Since I was starting with a complete fresh CentOS 8 system, the first thing I needed to do was install Ansible. Unfortunately, Ansible is not available in the default repos configured in CentOS 8, so the repo for it needs to be added first.

# Add EPEL repo
yum install epel-release
# Install Ansible
yum install ansible
# Confirm installation and version
ansible --version

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Managing Local Admins via vRealize Automation

One of the major benefits of vRealize Automation (vRA) is the ability to add and extend the “Actions” available. These Actions enable self-service by the customer. One scenario I wanted to try was allowing someone to manage local administrators on a virtual machine they had provisioned.

Creating The Workflow

The starting point with this is creating a Workflow in vRealize Orchestrator (vRO). Managing local administrators would mean being able to add and remove members, so if I wanted it as a single workflow, there would be some sort of branching logic, such as the flowchart below:

Simple Workflow

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Thoughts on User Experience and Automation

The title suggests an odd combination of topics. I believe there still is an aspect of User Experience in IT Automation. With Automation, a task that was previously performed by a person is being done with a script or the like. This is really one half of the scenario, as we are also replacing the interface our customer was using and putting a new one in place. In some cases, this new interface can be worse than what was in place before.

I’ve collected a number of observations and thoughts about this User Experience aspect and I’ll go through some of them in this article. The examples I present will be relating to PowerShell and vRealize Orchestrator since those are tools I use frequently. But they could probably apply to any language/technology scenario involving automation.

Using The Appropriate Input Channel

This is a “sin” I see often with some people when they first get into PowerShell. I suspect this sin occurs because they were thinking in the context of their script being executed interactively by the user. This leads them to use the cmdlet Read-Host to get input from the user. In a way, Read-Host is seductive in its use. It allows you to assign the user’s input to a variable. The prompt the user sees can also be customised.

Using Read-Host to ask for input
Using Read-Host to ask for a username

The problem with this approach is the script will wait for the user’s input. This makes it unsuitable for scenarios where the script would be programmatically executed. In the case of PowerShell specifically, using Read-Host instead of Parameters seems counter-intuitive to the Pipeline model that PowerShell uses, where objects can be easily passed from one command to another. Lastly, Read-Host has no validation of any sort, so performing validation of the input would require extra code. Which leads into the next item…

Using Input Validation

Input Validation can help serve two goals. Firstly providing immediate feedback to the consumer of your automation that something bad was entered. Secondly protecting your automation against undesirable inputs. A bad example the first goal: a coworker who was trying to update details on some Virtual Machines, which involved inputting a project code. He had entered a value that the system didn’t like, but only informed him after he had submitted the request. This created a poor user experience because he didn’t get immediate feedback. The result was he had to fill in and submit the form again.

In the story about the co-worker the form was the front-end of a workflow in vRealize Orchestrator. Assuming the project code was always going to be a number, this issue could’ve been fixed by setting the data type of the input to “number”. A better approach would’ve been to use data binding and bind a list of valid project codes to the input.

Number validation in vRealize Orchestrator
vRealize Orchestrator’s number validation

PowerShell has a good range of options for validating input as well, including regular expressions.

Expose Complexity When Required

I consider the wizard for creating an EC2 instance in AWS to be a good benchmark for this. It’s possible to only select the “What” of the instance (what it does). After this, the consumer can immediately select “Review and Launch” from the instance type screen. If they want more control over the details, then they can take a different path. However, taking the “express path” requires very little input or technical knowledge to provision the instance.

A bad example of this: a provisioning workflow prompted for about 15 pieces of information, including which data center the server would live in, which storage, what network zone and so on. In this case, an overwhelming amount of complexity was being exposed by default. It required the consumer of this workflow to have intimate knowledge of the organisation’s infrastructure. This immediately restricts the potential scope of consumers for this workflow, and thus reduces the benefits it would realise.

A middle ground example was a private cloud system I supported, that used similar technology to the bad example above. Consumers could provision a virtual machine with a few abstract pieces of information (what is the server’s role/job? Is it a dev, test or prod system?). However, under certain conditions, like the server’s home being production, more complexity was exposed. The consumer was prompted for things like backup settings. In this case, more complexity was exposed in a way that was appropriate.

Closing Thoughts

There are many more problematic user experience scenarios outside the ones I’ve mentioned. These issues can be negated with some consideration on what is presented to them. This results in a positive experience of those consumers. A positive experience means they’re likely to use it more often and that’s a good outcome.

Managing F5 Load Balancers with vRealize Orchestrator

F5 Load Balancers (LB) have been a common feature across a number of environments I’ve worked at. While administration of these devices is generally performed via the web interface, F5s also have a REST API that allows the same management tasks to be performed. This opens the possibility of using VMware’s vRealize Orchestrator (vRO) to manage F5 Load Balancers via the same REST API.

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Building Nutanix AHV Templates with Packer

Packer is a tool that many IT Infrastructure professions would be familiar with. Packer allows the creation of “machine images” (or base templates) in a way that’s consistent and highly repeatable. The result is machine images that can be used on a variety of platforms such as cloud providers like AWS or Azure or on-prem infrastructure like VMware, all configured to your organisation’s needs.

Nutanix has its own Virtual Machine format called AHV, which runs on Nutanix’s hypervisor Acropolis. Since this hypervisor is based off the KVM hypervisor, and Packer has support for KVM, Packer can be used to build templates for a Nutanix target platform. This post will detail the process I went through to create a Windows 2016 template for Nutanix.

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