Small improvements to process flow and communication (#190)

## Purpose

* Fixes a global ACR name collision that caused
`External-Configurator.ps1` to silently skip container registry creation
for any user who kept the default cluster name (`iot-ops-cluster`). The
auto-generated name `iotopsclusteracr` is already taken in Azure; the
fix appends a 6-character subscription ID suffix to make the name unique
per-subscription while keeping it deterministic across re-runs.
* Fixes an indefinite hang in `External-Configurator.ps1` and
`grant_entra_id_roles.ps1` when required Azure CLI extensions
(`azure-iot-ops`, `connectedk8s`, `k8s-extension`) are not installed.
Both scripts now check for all three extensions at startup, print the
exact install commands, and exit immediately rather than blocking.

## Does this introduce a breaking change?

```
[ ] Yes
[x] No
```

Existing users who already set a custom `container_registry` value are
unaffected. Users who relied on the old auto-generated name
(`<cluster>acr`) will get a new name on first run — but since the old
name was globally taken and ACR creation was silently skipped anyway,
there is no working state to break.

## Pull Request Type

```
[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Documentation content changes
[ ] Other... Please describe:
```

## How to Test

* Get the code

```
git clone [repo-address]
cd [repo-name]
git checkout [branch-name]
```

* Test Issue 1 (ACR name collision):
```powershell
# Use the default cluster name so the suffix logic is exercised
$env:AKSEDGE_CLUSTER_NAME = "iot-ops-cluster"
# Leave AZURE_CONTAINER_REGISTRY unset
cd quickstart/external_configuration
.\External-Configurator.ps1 -WhatIf   # or run normally in a test subscription
```

* Test Issue 2 (extension check):
```powershell
# Temporarily rename an extension to simulate it being absent
az extension remove --name connectedk8s
cd quickstart/external_configuration
.\External-Configurator.ps1
# Expect: immediate error listing missing extensions with install commands, no hang
.\grant_entra_id_roles.ps1
# Expect: same immediate error
# Restore
az extension add --upgrade --name connectedk8s
```

## What to Check

* ACR name printed in the yellow notice block includes a 6-character
suffix derived from the subscription ID (not the bare `<cluster>acr`
form).
* Re-running the script with the same subscription produces the same ACR
name (idempotent).
* Setting `container_registry` in `aio_config.json` or
`$env:AZURE_CONTAINER_REGISTRY` bypasses the auto-generation block
entirely — the yellow notice does not appear.
* With a missing extension, both `External-Configurator.ps1` and
`grant_entra_id_roles.ps1` exit within seconds with a red error listing
the missing extensions and the `az extension add` commands to fix them.
* With all three extensions installed, both scripts proceed normally
past the extension check.

## Other Information

The subscription ID suffix approach was chosen over a random suffix
because it keeps the name stable across re-runs (important for
idempotency) while still being unique across different Azure tenants and
subscriptions. The first 6 hex characters of a subscription ID provide
sufficient entropy for this purpose.

---------

Co-authored-by: william_harding <wharding@microsoft.com>

Author: BillmanH

quickstart/external_configuration/External-Configurator.ps1

@@ -205,17 +205,26 @@ function Test-Prerequisites {
         Write-ErrorLog "Azure CLI is not installed or not in PATH" -Fatal
     }
 
-    # Check for iot-ops extension
+    # Check for required CLI extensions — missing extensions cause az commands to hang indefinitely
     $extensions = az extension list --output json 2>$null | ConvertFrom-Json
-    $iotOpsExt = $extensions | Where-Object { $_.name -eq 'azure-iot-ops' }
-    
-    if (-not $iotOpsExt) {
-        Write-WarnLog "azure-iot-ops extension not found. Install it manually before continuing:"
-        Write-WarnLog "  az extension add --name azure-iot-ops --upgrade"
-        Write-WarnLog "Then re-run this script."
-        $allPassed = $false
-    } else {
-        Write-Success "azure-iot-ops extension version: $($iotOpsExt.version)"
+    $requiredCliExtensions = @('azure-iot-ops', 'connectedk8s', 'k8s-extension')
+    $missingExtensions = @()
+
+    foreach ($extName in $requiredCliExtensions) {
+        $ext = $extensions | Where-Object { $_.name -eq $extName }
+        if ($ext) {
+            Write-Success "$extName extension version: $($ext.version)"
+        } else {
+            $missingExtensions += $extName
+        }
+    }
+
+    if ($missingExtensions.Count -gt 0) {
+        Write-ErrorLog "The following required Azure CLI extensions are not installed:" -Fatal:$false
+        foreach ($extName in $missingExtensions) {
+            Write-ErrorLog "  az extension add --upgrade --name $extName" -Fatal:$false
+        }
+        Write-ErrorLog "Install the missing extensions above and re-run this script." -Fatal
     }
 
     # Check ARM templates directory
@@ -661,10 +670,18 @@ function Connect-ToAzure {
     }
 
     if (-not $script:ContainerRegistryName) {
-        # ACR names: 5-50 chars, alphanumeric only, globally unique
-        $script:ContainerRegistryName = ($clusterNameClean + "acr").Substring(0, [Math]::Min(50, ($clusterNameClean + "acr").Length))
+        # ACR names: 5-50 chars, alphanumeric only, globally unique.
+        # Append a 6-char suffix derived from the subscription ID to reduce global name collisions.
+        $suffix = ($script:SubscriptionId -replace '-', '').Substring(0, 6)
+        $baseName = $clusterNameClean + "acr" + $suffix
+        $script:ContainerRegistryName = $baseName.Substring(0, [Math]::Min(50, $baseName.Length))
         $script:ContainerRegistryLoginServer = "$($script:ContainerRegistryName).azurecr.io"
-        Write-InfoLog "Using auto-generated container registry name: $script:ContainerRegistryName"
+        Write-Host ""
+        Write-Host "  [ACR] No container_registry value was set — auto-generating a name." -ForegroundColor Yellow
+        Write-Host "  [ACR] Container Registry will be created as: $script:ContainerRegistryName" -ForegroundColor Yellow
+        Write-Host "  [ACR] To use your own name, set 'container_registry' in config/aio_config.json" -ForegroundColor Yellow
+        Write-Host "        or set `$env:AZURE_CONTAINER_REGISTRY before running this script." -ForegroundColor Yellow
+        Write-Host ""
     }
 
     if (-not $script:KeyVaultName) {

quickstart/external_configuration/grant_entra_id_roles.ps1

@@ -357,6 +357,28 @@ try {
     exit 1
 }
 
+# Check for required CLI extensions — missing extensions cause az commands to hang indefinitely
+$extensions = az extension list --output json 2>$null | ConvertFrom-Json
+$requiredCliExtensions = @('azure-iot-ops', 'connectedk8s', 'k8s-extension')
+$missingExtensions = @()
+
+foreach ($extName in $requiredCliExtensions) {
+    $ext = $extensions | Where-Object { $_.name -eq $extName }
+    if ($ext) {
+        Write-Success "$extName extension version: $($ext.version)"
+    } else {
+        $missingExtensions += $extName
+    }
+}
+
+if ($missingExtensions.Count -gt 0) {
+    Write-Host "ERROR: The following required Azure CLI extensions are not installed:" -ForegroundColor Red
+    $missingExtensions | ForEach-Object { Write-Host "  az extension add --upgrade --name $_" -ForegroundColor Yellow }
+    Write-Host "Install the missing extensions above and re-run this script." -ForegroundColor Red
+    Stop-Transcript
+    exit 1
+}
+
 # ============================================================================
 # AZURE AUTHENTICATION
 # ============================================================================

quickstart/readme.md

@@ -46,8 +46,9 @@ As the end-goal is an IoT solution, this repo has a preference for installing on
 
 
 # Quick Start
-The goal here is to install IoT Operations on an Ubuntu machine (like a local NUC, PC, or a VM) so that you can get working quickly on your dataflow pipelines and get data into Fabric quickly. 
-* _if you are in a purely testing or validation phase you can create a quick VM using [this process](quick_vm_build.md)_
+The goal of this quickstart is to install IoT Operations on an Ubuntu or Windows machine (like a local NUC, PC, or a VM) so that you can get working quickly on your dataflow pipelines and get data into Fabric quickly. Additionaly there are optional modules that you can use to deploy data simulators in your project.
+* _if you are in a purely testing or validation phase you can create a quick VM using [this process]
+(quick_vm_build.md)_
 * _if you are building on a Windows machine using AKS Edge Essentials, see the [Single Windows Machine (AKS-EE)](#path-b-single-windows-machine-aks-ee) section below._
 
 > **Using AKS Edge Essentials (Windows-based edge)?**