Little Nuggets

This section is just a list of little nuggets of code that can help with repetitive tasks.

Stop typing your credentials every time you run a script

This seems like a sensible thing to do but after 10 or more interactions it starts to wear.
Multiply this by the number of vCenters, HCX servers etc you need to access, its not funny.
For a script used a lot i.e. creating HCX Batches, I have used credential files in the example below:

Prompt for the server name first:

# Prompt the user for the source vCenter server FQDN, provides the default option
$sourcevCenter = Read-Host -Prompt "Enter the source vCenter server name (default: $sourcevCenterDefault)"
# If the user does not enter a server name, use the default value
if ([string]::IsNullOrWhiteSpace($sourcevCenter)) {
    $sourcevCenter = $sourcevCenterDefault
}

Now check if a credential file exists in the location the script was run from, if found, use them to connect, if not, take in new credentials, save to a new file and then use them:

# Source vCenter Credentials
$srcVcCredentialFilePath = ".\srcVcCredentials.xml"
# Check if credentials file exists
if (Test-Path -Path $srcVcCredentialFilePath) {
    # Load the credentials from the secure XML file if they exist
    $credential = Import-Clixml -Path $srcVcCredentialFilePath
    Write-Output "Using saved credentials for Source vCenter."
} else {
    $credential = Get-Credential -Message "Enter Source vCenter Credentials"
    $credential | Export-Clixml -Path $srcVcCredentialFilePath
    Write-Output "Credentials saved securely."
}
Connect-VIServer -Server $sourcevCenter -Credential $credential

One you have done this once, it will simply load the credential file saving you lots of repetitive typing.

The credential file itself hashes the password as shown:

Obviously there is a security concern here that someone ‘could’ take those credential files and re-use them to access the servers.
This is why they should reside on a limited access jumpbox where you need to be granted access, and if you have access, you probably have access to the passwords in the first place.

If security is a concern, you could edit the script to check the timestamp on the credential file and delete it when loading if older than say 1 hour and prompt to re-enter the password.

# Get the current date and time
$currentTime = Get-Date

# Get the last write time of the file
$fileLastWriteTime = (Get-Item $srcVcCredentialFilePath).LastWriteTime

# Calculate the time difference
$timeDifference = $currentTime - $fileLastWriteTime

# Check if the time difference is greater than 1 hour (3600 seconds)
if ($timeDifference.TotalSeconds -gt 3600) {
    # Delete the file
    Remove-Item $srcVcCredentialFilePath
    Write-Host "Credential file $srcVcCredentialFilePath deleted."
} else {
    Write-Host "Credential $srcVcCredentialFilePath is still valid."
}

Writing to a log

Sometimes it’s good to make a log of what a task is doing, this can also help with rollback and troubleshooting.

The same code below simply creates a log based on the file ‘HCX Migration Batch’ name you are processing and the message you wish to write:

Updating a CSV with live data

When using a CSV file as input, you may want to update it or make a copy of it with dynamic data or results from your scripts.
The function below allows you to pass the CSV file and path, the VM name to find the row to update, The Header name to find the column to update and then the payload you wish to write.

How I have been using this is to document values for VMs being migrated i.e. what Port Group each NIC is mapped to for source and Target.