From d426ca1098b8882f0237861ae1fbd983b91ddd18 Mon Sep 17 00:00:00 2001
From: Tim Wright <wrightt@microsoft.com>
Date: Mon, 9 Feb 2026 02:43:18 +0000
Subject: [PATCH 1/4] better error

---
 staging/cse/windows/kubernetesfunc.ps1 | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/staging/cse/windows/kubernetesfunc.ps1 b/staging/cse/windows/kubernetesfunc.ps1
index 0cc784796ea..c921fd4af62 100644
--- a/staging/cse/windows/kubernetesfunc.ps1
+++ b/staging/cse/windows/kubernetesfunc.ps1
@@ -182,6 +182,7 @@ function Check-APIServerConnectivity {
     )
     Logs-To-Event -TaskName "AKS.WindowsCSE.CheckAPIServerConnectivity" -TaskMessage "Start to check API server connectivity."
     $retryCount=0
+    $LastException=$null
 
     do {
         $retryString="${retryCount}/${MaxRetryCount}"
@@ -202,16 +203,18 @@ function Check-APIServerConnectivity {
             $tcpClient.Close()
         } catch [System.AggregateException] {
             Write-Log "Retry ${retryString}: Failed to connect to API server $MasterIP. AggregateException: " + $_.Exception.ToString()
+            $LastException = $_.Exception.ToString()
         } catch {
             Write-Log "Retry ${retryString}: Failed to connect to API server $MasterIP. Error: $_"
-        }
+            $LastException = $_.ToString()
+      }
 
         $retryCount++
         Write-Log "Retry ${retryString}: Sleep $RetryInterval and then retry to connect to API server"
         Sleep $RetryInterval
     } while ($retryCount -lt $MaxRetryCount)
 
-    Set-ExitCode -ExitCode $global:WINDOWS_CSE_ERROR_CHECK_API_SERVER_CONNECTIVITY -ErrorMessage "Failed to connect to API server $MasterIP after $retryCount retries"
+    Set-ExitCode -ExitCode $global:WINDOWS_CSE_ERROR_CHECK_API_SERVER_CONNECTIVITY -ErrorMessage "Failed to connect to API server $MasterIP after $retryCount retries. Last exception: $LastException"
 }
 
 function Get-CACertificates {

From c55fcd3a5366937f3dce38fabe7661451ded92d2 Mon Sep 17 00:00:00 2001
From: Tim Wright <wrightt@microsoft.com>
Date: Mon, 9 Feb 2026 03:44:58 +0000
Subject: [PATCH 2/4] log to event

---
 staging/cse/windows/kubernetesfunc.ps1 | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/staging/cse/windows/kubernetesfunc.ps1 b/staging/cse/windows/kubernetesfunc.ps1
index c921fd4af62..9b47e896daf 100644
--- a/staging/cse/windows/kubernetesfunc.ps1
+++ b/staging/cse/windows/kubernetesfunc.ps1
@@ -202,10 +202,10 @@ function Check-APIServerConnectivity {
             }
             $tcpClient.Close()
         } catch [System.AggregateException] {
-            Write-Log "Retry ${retryString}: Failed to connect to API server $MasterIP. AggregateException: " + $_.Exception.ToString()
+            Logs-To-Event -TaskName "AKS.WindowsCSE.CheckAPIServerConnectivity" -TaskMessage "Retry ${retryString}: Failed to connect to API server $MasterIP. AggregateException: " + $_.Exception.ToString()
             $LastException = $_.Exception.ToString()
         } catch {
-            Write-Log "Retry ${retryString}: Failed to connect to API server $MasterIP. Error: $_"
+            Logs-To-Event -TaskName "AKS.WindowsCSE.CheckAPIServerConnectivity" -TaskMessage "Retry ${retryString}: Failed to connect to API server $MasterIP. Error: $_"
             $LastException = $_.ToString()
       }
 

From d1b6d85b935454c1adcc43fa7cf361a75e053fec Mon Sep 17 00:00:00 2001
From: Tim Wright <wrightt@microsoft.com>
Date: Mon, 9 Feb 2026 03:47:55 +0000
Subject: [PATCH 3/4] better last exception

---
 staging/cse/windows/kubernetesfunc.ps1 | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/staging/cse/windows/kubernetesfunc.ps1 b/staging/cse/windows/kubernetesfunc.ps1
index 9b47e896daf..fdeba487925 100644
--- a/staging/cse/windows/kubernetesfunc.ps1
+++ b/staging/cse/windows/kubernetesfunc.ps1
@@ -206,7 +206,7 @@ function Check-APIServerConnectivity {
             $LastException = $_.Exception.ToString()
         } catch {
             Logs-To-Event -TaskName "AKS.WindowsCSE.CheckAPIServerConnectivity" -TaskMessage "Retry ${retryString}: Failed to connect to API server $MasterIP. Error: $_"
-            $LastException = $_.ToString()
+            $LastException = "$_"
       }
 
         $retryCount++

From da4cc145d68bb9434e73a97c01fe699d6890c382 Mon Sep 17 00:00:00 2001
From: Tim Wright <wrightt@microsoft.com>
Date: Wed, 11 Feb 2026 10:02:56 +1300
Subject: [PATCH 4/4] Update staging/cse/windows/kubernetesfunc.ps1

Co-authored-by: Copilot <175728472+Copilot@users.noreply.github.com>
---
 staging/cse/windows/kubernetesfunc.ps1 | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/staging/cse/windows/kubernetesfunc.ps1 b/staging/cse/windows/kubernetesfunc.ps1
index fdeba487925..ec2ff53c04b 100644
--- a/staging/cse/windows/kubernetesfunc.ps1
+++ b/staging/cse/windows/kubernetesfunc.ps1
@@ -214,7 +214,18 @@ function Check-APIServerConnectivity {
         Sleep $RetryInterval
     } while ($retryCount -lt $MaxRetryCount)
 
-    Set-ExitCode -ExitCode $global:WINDOWS_CSE_ERROR_CHECK_API_SERVER_CONNECTIVITY -ErrorMessage "Failed to connect to API server $MasterIP after $retryCount retries. Last exception: $LastException"
+    $lastExceptionMessage = ""
+    if ($LastException -ne $null) {
+        if ($LastException.Exception -ne $null -and -not [string]::IsNullOrEmpty($LastException.Exception.Message)) {
+            $lastExceptionMessage = $LastException.Exception.Message
+        } else {
+            $lastExceptionMessage = $LastException.ToString()
+        }
+        # Normalize any CR/LF in the exception message to spaces to keep ErrorMessage single-line.
+        $lastExceptionMessage = $lastExceptionMessage -replace "(`r|`n)+", " "
+    }
+
+    Set-ExitCode -ExitCode $global:WINDOWS_CSE_ERROR_CHECK_API_SERVER_CONNECTIVITY -ErrorMessage "Failed to connect to API server $MasterIP after $retryCount retries. Last exception: $lastExceptionMessage"
 }
 
 function Get-CACertificates {