Let’s Automate VMware Part 1: Introduction and Packer Prerequisites

Just a little warning up front: I’ve never done this before. I’m taking a journey into slowly replacing myself with a small shell script, or at least with some automation tools. I’m completely new to this and working my way through it with the official documentation, a little bit of Googling and my cobbled-together vSphere 6.7 homelab. Feel free to join me on this journey, but please don’t blame me if you try this in your environment and get eaten by a grue.

Ultimately, the goal this project is to completely automate my homelab, from hardware provisioning to hypervisor installation, cluster management, image management, package management, log aggregation and backups. Stretch goals include extending into the cloud, a CI/CD pipeline and “employee” self service.

My first part of this journey was building base images so I would have something to operate, back up and manage. This seemed like a logical place to start as this was “low hanging fruit” that would be easy to implement in any environment where VMs are deployed regularly. But rather than hand-building some base CentOS and Windows templates, it made sense to delve into using Packer to build these templates for me. So in the next couple of blog posts, I will use Packer to build base Linux and Windows images that I can use as templates in my VMware environment, and then schedule Packer to keep those images up-to-date.

While I could run Packer straight from my desktop, ultimately I wanted to have this code running on a dedicated virtual machine in my environment. I created a barebones Linux VM based on CentOS 8 that I named ‘automation’ as the base for all of this activity. While I’m using CentOS 8 for this, feel free to use whatever *nix you want or even Windows–Packer itself is platform agnostic.

A quick note up front: some versions of RedHat derivatives, including CentOS 8, already have a program called “packer”, which is related to cracklib, a library for checking passwords for good entropy. It’s actually a link to another binary, so I bypassed the name collision issue altogether by issuing an “unlink /usr/sbin/packer” command without any regard for whether it might break the rest of the system. Do this at your own peril.

Installation was straightforward. I downloaded the Linux x64 binary from the Packer website (https://www.packer.io/downloads.html) and unzipped it into /usr/local. Running /usr/local/packer without any arguments proved that it was working. You can also find prebuilt packages for Packer or compile it yourself.

My next step was to get permissions to my vSphere cluster. Packer uses the vSphere API, and the permissions needed can be found in Packer’s documentation for the vSphere builders. I fired up the vSphere client to create a user called “automation” and assign it to the Administrators group. I then logged into the vCenter using PowerCLI in PowerShell:

Connect-VIServer -server vcsa.lab.clev.work

After allowing the vCenter certificate, I entered the credentials for the new ‘automation’ user into the popup dialog box and connected. To test my new user, I connected my datastore called “datastore2” to a local PowerShell mount called “isostore”, and then uploaded the latest CentOS ISO to the “iso” folder on that datastore.

New-PSDrive -Location (Get-Datastore "storage2") -Name isostore -PSProvider VimDatastore -Root "\"
Copy-DatastoreItem -Item d:\isos\CentOS-8.1.1911-x86_64-dvd1.iso -Destination isostore:\iso\

Note that this process is slow; the upload took about 20 minutes in my homelab and the progress bar in PowerCLI did not move during the copy. Fortunately, I could see the file growing in the vSphere client as the upload proceeded. In the next post, I use my freshly-uploaded ISO to build my first Linux image from my ‘automation’ VM.

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