diff --git a/custom-words.txt b/custom-words.txt
index 21f47057170d..374d18f608ec 100644
--- a/custom-words.txt
+++ b/custom-words.txt
@@ -808,6 +808,8 @@ Gloo
 gltf
 gluster
 glusterfs
+gmsa
+Gmsa
 GOARCH
 GPUMIG
 GPUP
diff --git a/specification/containerservice/resource-manager/Microsoft.ContainerService/stable/2021-09-01/examples/ManagedClustersCreate_UpdateWindowsGmsa.json b/specification/containerservice/resource-manager/Microsoft.ContainerService/stable/2021-09-01/examples/ManagedClustersCreate_UpdateWindowsGmsa.json
new file mode 100644
index 000000000000..804f629548dd
--- /dev/null
+++ b/specification/containerservice/resource-manager/Microsoft.ContainerService/stable/2021-09-01/examples/ManagedClustersCreate_UpdateWindowsGmsa.json
@@ -0,0 +1,281 @@
+{
+  "parameters": {
+    "api-version": "2021-09-01",
+    "subscriptionId": "subid1",
+    "resourceGroupName": "rg1",
+    "resourceName": "clustername1",
+    "parameters": {
+      "location": "location1",
+      "tags": {
+        "tier": "production",
+        "archv2": ""
+      },
+      "sku": {
+        "name": "Basic",
+        "tier": "Free"
+      },
+      "properties": {
+        "kubernetesVersion": "",
+        "dnsPrefix": "dnsprefix1",
+        "agentPoolProfiles": [
+          {
+            "name": "nodepool1",
+            "count": 3,
+            "vmSize": "Standard_DS1_v2",
+            "osType": "Linux",
+            "type": "VirtualMachineScaleSets",
+            "availabilityZones": [
+              "1",
+              "2",
+              "3"
+            ],
+            "enableNodePublicIP": true,
+            "mode": "System"
+          }
+        ],
+        "linuxProfile": {
+          "adminUsername": "azureuser",
+          "ssh": {
+            "publicKeys": [
+              {
+                "keyData": "keydata"
+              }
+            ]
+          }
+        },
+        "networkProfile": {
+          "loadBalancerSku": "standard",
+          "outboundType": "loadBalancer",
+          "loadBalancerProfile": {
+            "managedOutboundIPs": {
+              "count": 2
+            }
+          }
+        },
+        "autoScalerProfile": {
+          "scan-interval": "20s",
+          "scale-down-delay-after-add": "15m"
+        },
+        "windowsProfile": {
+          "adminUsername": "azureuser",
+          "adminPassword": "replacePassword1234$",
+          "gmsaProfile": {
+            "enabled": true
+          }
+        },
+        "servicePrincipalProfile": {
+          "clientId": "clientid",
+          "secret": "secret"
+        },
+        "addonProfiles": {},
+        "enableRBAC": true,
+        "diskEncryptionSetID": "/subscriptions/subid1/resourceGroups/rg1/providers/Microsoft.Compute/diskEncryptionSets/des",
+        "enablePodSecurityPolicy": true
+      },
+      "identity": {
+        "type": "UserAssigned",
+        "userAssignedIdentities": {
+          "/subscriptions/subid1/resourceGroups/rgName1/providers/Microsoft.ManagedIdentity/userAssignedIdentities/identity1": {}
+        }
+      }
+    }
+  },
+  "responses": {
+    "200": {
+      "body": {
+        "id": "/subscriptions/subid1/resourcegroups/rg1/providers/Microsoft.ContainerService/managedClusters/clustername1",
+        "location": "location1",
+        "name": "clustername1",
+        "tags": {
+          "archv2": "",
+          "tier": "production"
+        },
+        "type": "Microsoft.ContainerService/ManagedClusters",
+        "properties": {
+          "provisioningState": "Succeeded",
+          "maxAgentPools": 1,
+          "kubernetesVersion": "1.9.6",
+          "dnsPrefix": "dnsprefix1",
+          "agentPoolProfiles": [
+            {
+              "name": "nodepool1",
+              "count": 3,
+              "vmSize": "Standard_DS1_v2",
+              "maxPods": 110,
+              "osType": "Linux",
+              "provisioningState": "Succeeded",
+              "orchestratorVersion": "1.9.6",
+              "type": "VirtualMachineScaleSets",
+              "availabilityZones": [
+                "1",
+                "2",
+                "3"
+              ],
+              "enableNodePublicIP": true,
+              "mode": "System",
+              "nodeImageVersion": "AKSUbuntu:1604:2020.03.11"
+            }
+          ],
+          "linuxProfile": {
+            "adminUsername": "azureuser",
+            "ssh": {
+              "publicKeys": [
+                {
+                  "keyData": "keydata"
+                }
+              ]
+            }
+          },
+          "windowsProfile": {
+            "adminUsername": "azureuser",
+            "gmsaProfile": {
+              "enabled": true
+            }
+          },
+          "servicePrincipalProfile": {
+            "clientId": "clientid"
+          },
+          "nodeResourceGroup": "MC_rg1_clustername1_location1",
+          "enableRBAC": true,
+          "diskEncryptionSetID": "/subscriptions/subid1/resourceGroups/rg1/providers/Microsoft.Compute/diskEncryptionSets/des",
+          "enablePodSecurityPolicy": true,
+          "fqdn": "dnsprefix1-abcd1234.hcp.eastus.azmk8s.io",
+          "networkProfile": {
+            "loadBalancerSku": "basic",
+            "networkPlugin": "kubenet",
+            "podCidr": "10.244.0.0/16",
+            "serviceCidr": "10.0.0.0/16",
+            "dnsServiceIP": "10.0.0.10",
+            "dockerBridgeCidr": "172.17.0.1/16",
+            "outboundType": "loadBalancer",
+            "loadBalancerProfile": {
+              "allocatedOutboundPorts": 2000,
+              "idleTimeoutInMinutes": 10,
+              "managedOutboundIPs": {
+                "count": 2
+              },
+              "effectiveOutboundIPs": [
+                {
+                  "id": "/subscriptions/subid1/resourceGroups/MC_rg1/providers/Microsoft.Network/publicIPAddresses/mgdoutboundip1"
+                },
+                {
+                  "id": "/subscriptions/subid1/resourceGroups/MC_rg1/providers/Microsoft.Network/publicIPAddresses/mgdoutboundip2"
+                }
+              ]
+            }
+          },
+          "autoScalerProfile": {
+            "scan-interval": "20s",
+            "scale-down-delay-after-add": "15m"
+          }
+        },
+        "identity": {
+          "type": "UserAssigned",
+          "userAssignedIdentities": {
+            "/subscriptions/subid1/resourceGroups/rgName1/providers/Microsoft.ManagedIdentity/userAssignedIdentities/identity1": {
+              "principalId": "principalId1",
+              "clientId": "clientId1"
+            }
+          }
+        }
+      }
+    },
+    "201": {
+      "body": {
+        "id": "/subscriptions/subid1/resourcegroups/rg1/providers/Microsoft.ContainerService/managedClusters/clustername1",
+        "location": "location1",
+        "name": "clustername1",
+        "tags": {
+          "archv2": "",
+          "tier": "production"
+        },
+        "type": "Microsoft.ContainerService/ManagedClusters",
+        "properties": {
+          "provisioningState": "Creating",
+          "maxAgentPools": 1,
+          "kubernetesVersion": "1.9.6",
+          "dnsPrefix": "dnsprefix1",
+          "agentPoolProfiles": [
+            {
+              "name": "nodepool1",
+              "count": 3,
+              "vmSize": "Standard_DS1_v2",
+              "maxPods": 110,
+              "osType": "Linux",
+              "provisioningState": "Creating",
+              "orchestratorVersion": "1.9.6",
+              "type": "VirtualMachineScaleSets",
+              "availabilityZones": [
+                "1",
+                "2",
+                "3"
+              ],
+              "enableNodePublicIP": true,
+              "mode": "System"
+            }
+          ],
+          "linuxProfile": {
+            "adminUsername": "azureuser",
+            "ssh": {
+              "publicKeys": [
+                {
+                  "keyData": "keydata"
+                }
+              ]
+            }
+          },
+          "windowsProfile": {
+            "adminUsername": "azureuser",
+            "gmsaProfile": {
+              "enabled": true
+            }
+          },
+          "servicePrincipalProfile": {
+            "clientId": "clientid"
+          },
+          "nodeResourceGroup": "MC_rg1_clustername1_location1",
+          "enableRBAC": true,
+          "diskEncryptionSetID": "/subscriptions/subid1/resourceGroups/rg1/providers/Microsoft.Compute/diskEncryptionSets/des",
+          "enablePodSecurityPolicy": true,
+          "networkProfile": {
+            "networkPlugin": "kubenet",
+            "podCidr": "10.244.0.0/16",
+            "serviceCidr": "10.0.0.0/16",
+            "dnsServiceIP": "10.0.0.10",
+            "dockerBridgeCidr": "172.17.0.1/16",
+            "loadBalancerSku": "standard",
+            "outboundType": "loadBalancer",
+            "loadBalancerProfile": {
+              "allocatedOutboundPorts": 2000,
+              "idleTimeoutInMinutes": 10,
+              "managedOutboundIPs": {
+                "count": 2
+              },
+              "effectiveOutboundIPs": [
+                {
+                  "id": "/subscriptions/subid1/resourceGroups/MC_rg1/providers/Microsoft.Network/publicIPAddresses/mgdoutboundip1"
+                },
+                {
+                  "id": "/subscriptions/subid1/resourceGroups/MC_rg1/providers/Microsoft.Network/publicIPAddresses/mgdoutboundip2"
+                }
+              ]
+            }
+          },
+          "autoScalerProfile": {
+            "scan-interval": "20s",
+            "scale-down-delay-after-add": "15m"
+          }
+        },
+        "identity": {
+          "type": "UserAssigned",
+          "userAssignedIdentities": {
+            "/subscriptions/subid1/resourceGroups/rgName1/providers/Microsoft.ManagedIdentity/userAssignedIdentities/identity1": {
+              "principalId": "principalId1",
+              "clientId": "clientId1"
+            }
+          }
+        }
+      }
+    }
+  }
+}
diff --git a/specification/containerservice/resource-manager/Microsoft.ContainerService/stable/2021-09-01/managedClusters.json b/specification/containerservice/resource-manager/Microsoft.ContainerService/stable/2021-09-01/managedClusters.json
index c7152fd0f838..da5b47aac154 100644
--- a/specification/containerservice/resource-manager/Microsoft.ContainerService/stable/2021-09-01/managedClusters.json
+++ b/specification/containerservice/resource-manager/Microsoft.ContainerService/stable/2021-09-01/managedClusters.json
@@ -564,6 +564,9 @@
           },
           "Create Managed Cluster using an agent pool snapshot": {
             "$ref": "./examples/ManagedClustersCreate_Snapshot.json"
+          },
+          "Create/Update Managed Cluster with Windows gMSA enabled": {
+            "$ref": "./examples/ManagedClustersCreate_UpdateWindowsGmsa.json"
           }
         }
       },
@@ -2929,6 +2932,10 @@
           "type": "boolean",
           "title": "Whether to enable CSI proxy.",
           "description": "For more details on CSI proxy, see the [CSI proxy GitHub repo](https://github.com/kubernetes-csi/csi-proxy)."
+        },
+        "gmsaProfile": {
+          "$ref": "#/definitions/WindowsGmsaProfile",
+          "description": "The Windows gMSA Profile in the Managed Cluster."
         }
       },
       "required": [
@@ -2936,6 +2943,25 @@
       ],
       "description": "Profile for Windows VMs in the managed cluster."
     },
+    "WindowsGmsaProfile": {
+      "type": "object",
+      "properties": {
+        "enabled": {
+          "type": "boolean",
+          "title": "Whether to enable Windows gMSA.",
+          "description": "Specifies whether to enable Windows gMSA in the managed cluster."
+        },
+        "dnsServer": {
+          "type": "string",
+          "description": "Specifies the DNS server for Windows gMSA. <br><br> Set it to empty if you have configured the DNS server in the vnet which is used to create the managed cluster."
+        },
+        "rootDomainName": {
+          "type": "string",
+          "description": "Specifies the root domain name for Windows gMSA. <br><br> Set it to empty if you have configured the DNS server in the vnet which is used to create the managed cluster."
+        }
+      },
+      "description": "Windows gMSA Profile in the managed cluster."
+    },
     "ContainerServiceLinuxProfile": {
       "properties": {
         "adminUsername": {
diff --git a/specification/containerservice/resource-manager/readme.go.md b/specification/containerservice/resource-manager/readme.go.md
index 792722c739ae..1f7d147da198 100644
--- a/specification/containerservice/resource-manager/readme.go.md
+++ b/specification/containerservice/resource-manager/readme.go.md
@@ -20,6 +20,7 @@ azure-arm: true
 
 ``` yaml $(go) && $(multiapi)
 batch:
+  - tag: package-2021-09
   - tag: package-2021-08
   - tag: package-2021-07
   - tag: package-2021-05
@@ -50,6 +51,16 @@ batch:
   - tag: package-2017-07
 ```
 
+### Tag: package-2021-09 and go
+
+These settings apply only when `--package-2021-09 --go` is specified on the command line.
+Please also specify `--go-sdk-folder=<path to the root directory of your azure-sdk-for-go clone>`.
+
+``` yaml $(tag)=='package-2021-09' && $(go)
+namespace: containerservice
+output-folder: $(go-sdk-folder)/services/$(namespace)/mgmt/2021-09-01/$(namespace)
+```
+
 ### Tag: package-2021-08 and go
 
 These settings apply only when `--package-2021-08 --go` is specified on the command line.
diff --git a/specification/containerservice/resource-manager/readme.java.md b/specification/containerservice/resource-manager/readme.java.md
index 7d53a96b35dd..5834e2175ece 100644
--- a/specification/containerservice/resource-manager/readme.java.md
+++ b/specification/containerservice/resource-manager/readme.java.md
@@ -38,6 +38,20 @@ batch:
   - tag: package-2021-05
   - tag: package-2021-07
   - tag: package-2021-08
+  - tag: package-2021-09
+```
+
+### Tag: package-2021-09 and java
+
+These settings apply only when `--tag=package-2021-09` is specified on the command line.
+Please also specify `--azure-libraries-for-java-folder=<path to the root directory of your azure-sdk-for-java clone>`.
+
+``` yaml $(tag) == 'package-2021-09' && $(java) && $(multiapi)
+java:
+  namespace: com.microsoft.azure.management.containerservice.v2021_09_01
+  output-folder: $(azure-libraries-for-java-folder)/sdk/containerservice/mgmt-v2021_09_01
+regenerate-manager: true
+generate-interface: true
 ```
 
 ### Tag: package-2021-08 and java
diff --git a/specification/containerservice/resource-manager/readme.md b/specification/containerservice/resource-manager/readme.md
index 5f28376461b5..86bb0e4c63f0 100644
--- a/specification/containerservice/resource-manager/readme.md
+++ b/specification/containerservice/resource-manager/readme.md
@@ -46,6 +46,7 @@ These settings apply only when `--tag=package-2021-09` is specified on the comma
 input-file:
   - Microsoft.ContainerService/stable/2021-09-01/managedClusters.json
 ```
+
 ### Tag: package-2021-08
 
 These settings apply only when `--tag=package-2021-08` is specified on the command line.
@@ -355,6 +356,19 @@ input-file:
 
 ```
 
+### Tag: package-2021-09-01-only
+
+These settings apply only when `--tag=package-2021-09-01-only` is specified on the command line.
+
+``` yaml $(tag) == 'package-2021-09-01-only'
+input-file:
+- Microsoft.ContainerService/stable/2021-09-01/managedClusters.json
+directive:
+  - suppress: DefinitionsPropertiesNamesCamelCase
+    where: $.definitions.ManagedClusterProperties.properties.autoScalerProfile
+    reason: Cluster-autoscaler settings are not camel-cased
+```
+
 ### Tag: package-2021-08-01-only
 
 These settings apply only when `--tag=package-2021-08-01-only` is specified on the command line.
diff --git a/specification/containerservice/resource-manager/readme.python.md b/specification/containerservice/resource-manager/readme.python.md
index 9e13e102aecc..f966032e68b3 100644
--- a/specification/containerservice/resource-manager/readme.python.md
+++ b/specification/containerservice/resource-manager/readme.python.md
@@ -17,6 +17,7 @@ Generate all API versions currently shipped for this package
 
 ```yaml $(python) && $(multiapi) && $(track2)
 batch:
+  - tag: package-2021-09-01-only
   - tag: package-2021-08-01-only
   - tag: package-2021-07-01-only
   - tag: package-2021-05-01-only
@@ -53,6 +54,16 @@ clear-output-folder: false
 perform-load: false
 ```
 
+### Tag: package-2021-09-01-only and python
+
+These settings apply only when `--tag=package-2021-09-01-only --python` is specified on the command line.
+Please also specify `--python-sdks-folder=<path to the root directory of your azure-sdk-for-python clone>`.
+
+``` yaml $(tag) == 'package-2021-09-01-only' && $(python)
+namespace: azure.mgmt.containerservice.v2021_09_01
+output-folder: $(python-sdks-folder)/containerservice/azure-mgmt-containerservice/azure/mgmt/containerservice/v2021_09_01
+```
+
 ### Tag: package-2021-08-01-only and python
 
 These settings apply only when `--tag=package-2021-08-01-only --python` is specified on the command line.