Create a Test Environment for PowerCLI Scripts

Background:

One of the geeks wanted help using the Networking and iSCSI Configuration starter scripts from our blog post earlier in the year; Starter Scripts for ESXi Hosts.

A few days after getting the script tuned for their needs, they mentioned not having any hosts available to test the script, and they were caught off guard when I asked why they weren’t using a few nested ESXi hosts to test the script prior to their new hosts being available.

Reasons to use nested hosts, for testing scripts only:

Nested hosts restart faster than physical hosts.
Snapshot their working state and revert back to that state after testing your script(s).
Access DCUI of the host through console in vCenter.
- You may make changes to the management network of the host and would lose access without an out-of-band solution.

This post will focus on taking a snapshot of the nested hosts’ working state and reverting to that state after testing your script(s).

The PowerCLI script, “revert_test_vms.ps1” referenced in this post, is available on our public GitHub repo: https://github.com/humbledgeeks/amount

Script Information: “revert_test_vms.ps1”

Stop the nested hosts.
Revert to the preferred snapshot.
Start the nested hosts.

Assumptions:

Create two, or three, nested ESXi hosts.
- We gave each nested host:
  - vCPU = 2
  - vRAM = 6GB
  - vHDD = 80GB
  - vNIC = 2, you can add more NICs to match the physical hosts in your environment.
Place those hosts in a folder named “test-scripts”.
- If you prefer a different name, you will need to change the ‘-Location’ value in the PowerCLI script to match that folder name.
Configure the management network on each host to make them accessible after reverting to their snapshot.
Shut down the nested hosts after the management network configuration is completed.
Download the “revert_test_vms.ps1” script or copy its contents into PowerShell.