diff --git a/schemas/2019-04-01/Microsoft.ContainerService.json b/schemas/2019-04-01/Microsoft.ContainerService.json
index 91af724f82..348d1ea7bc 100644
--- a/schemas/2019-04-01/Microsoft.ContainerService.json
+++ b/schemas/2019-04-01/Microsoft.ContainerService.json
@@ -1240,12 +1240,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2019-06-01/Microsoft.ContainerService.json b/schemas/2019-06-01/Microsoft.ContainerService.json
index 3e87997236..5de019b237 100644
--- a/schemas/2019-06-01/Microsoft.ContainerService.json
+++ b/schemas/2019-06-01/Microsoft.ContainerService.json
@@ -1338,12 +1338,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2019-08-01/Microsoft.ContainerService.json b/schemas/2019-08-01/Microsoft.ContainerService.json
index bcb1463f2b..12c29b9b8a 100644
--- a/schemas/2019-08-01/Microsoft.ContainerService.json
+++ b/schemas/2019-08-01/Microsoft.ContainerService.json
@@ -1490,12 +1490,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2019-10-01/Microsoft.ContainerService.json b/schemas/2019-10-01/Microsoft.ContainerService.json
index 4c32974871..0f29e89189 100644
--- a/schemas/2019-10-01/Microsoft.ContainerService.json
+++ b/schemas/2019-10-01/Microsoft.ContainerService.json
@@ -1490,12 +1490,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2019-11-01/Microsoft.ContainerService.json b/schemas/2019-11-01/Microsoft.ContainerService.json
index 58a83e6f14..d75d63e607 100644
--- a/schemas/2019-11-01/Microsoft.ContainerService.json
+++ b/schemas/2019-11-01/Microsoft.ContainerService.json
@@ -1625,12 +1625,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2020-01-01/Microsoft.ContainerService.json b/schemas/2020-01-01/Microsoft.ContainerService.json
index 7fb84fa203..54616fd4cd 100644
--- a/schemas/2020-01-01/Microsoft.ContainerService.json
+++ b/schemas/2020-01-01/Microsoft.ContainerService.json
@@ -1629,12 +1629,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2020-02-01/Microsoft.ContainerService.json b/schemas/2020-02-01/Microsoft.ContainerService.json
index 16751053cc..c6e5bd7336 100644
--- a/schemas/2020-02-01/Microsoft.ContainerService.json
+++ b/schemas/2020-02-01/Microsoft.ContainerService.json
@@ -1711,12 +1711,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2020-03-01/Microsoft.ContainerService.json b/schemas/2020-03-01/Microsoft.ContainerService.json
index 3ee3a024ad..39cf5df7c9 100644
--- a/schemas/2020-03-01/Microsoft.ContainerService.json
+++ b/schemas/2020-03-01/Microsoft.ContainerService.json
@@ -1809,12 +1809,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2020-04-01/Microsoft.ContainerService.json b/schemas/2020-04-01/Microsoft.ContainerService.json
index 06428fde6f..970597841d 100644
--- a/schemas/2020-04-01/Microsoft.ContainerService.json
+++ b/schemas/2020-04-01/Microsoft.ContainerService.json
@@ -1847,12 +1847,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2020-06-01/Microsoft.ContainerService.json b/schemas/2020-06-01/Microsoft.ContainerService.json
index 81ce6a2fee..5e67abe7e6 100644
--- a/schemas/2020-06-01/Microsoft.ContainerService.json
+++ b/schemas/2020-06-01/Microsoft.ContainerService.json
@@ -1967,12 +1967,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         }
       },
       "required": [
diff --git a/schemas/2020-07-01/Microsoft.ContainerService.json b/schemas/2020-07-01/Microsoft.ContainerService.json
index 157f84a543..b5eceef712 100644
--- a/schemas/2020-07-01/Microsoft.ContainerService.json
+++ b/schemas/2020-07-01/Microsoft.ContainerService.json
@@ -1959,12 +1959,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         },
         "licenseType": {
           "oneOf": [
diff --git a/schemas/2020-09-01/Microsoft.ContainerService.json b/schemas/2020-09-01/Microsoft.ContainerService.json
index e1a172ceb2..fca2ffa9d9 100644
--- a/schemas/2020-09-01/Microsoft.ContainerService.json
+++ b/schemas/2020-09-01/Microsoft.ContainerService.json
@@ -2022,12 +2022,28 @@
       "type": "object",
       "properties": {
         "adminPassword": {
-          "type": "string",
-          "description": "Specifies the password of the administrator account. <br><br> **Minimum-length:** 8 characters <br><br> **Max-length:** 123 characters <br><br> **Complexity requirements:** 3 out of 4 conditions below need to be fulfilled <br> Has lower characters <br>Has upper characters <br> Has a digit <br> Has a special character (Regex match [\\W_]) <br><br> **Disallowed values:** \"abc@123\", \"P@$$w0rd\", \"P@ssw0rd\", \"P@ssword123\", \"Pa$$word\", \"pass@word1\", \"Password!\", \"Password1\", \"Password22\", \"iloveyou!\""
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^(?=.*[a-z])(?=.*[A-Z])(?=.*[!@#$%\\^&\\*\\(\\)])[a-zA-Z\\d!@#$%\\^&\\*\\(\\)]{12,123}$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator password to use for Windows VMs."
         },
         "adminUsername": {
-          "type": "string",
-          "description": "Specifies the name of the administrator account. <br><br> **restriction:** Cannot end in \".\" <br><br> **Disallowed values:** \"administrator\", \"admin\", \"user\", \"user1\", \"test\", \"user2\", \"test1\", \"user3\", \"admin1\", \"1\", \"123\", \"a\", \"actuser\", \"adm\", \"admin2\", \"aspnet\", \"backup\", \"console\", \"david\", \"guest\", \"john\", \"owner\", \"root\", \"server\", \"sql\", \"support\", \"support_388945a0\", \"sys\", \"test2\", \"test3\", \"user4\", \"user5\". <br><br> **Minimum-length:** 1 character <br><br> **Max-length:** 20 characters"
+          "oneOf": [
+            {
+              "type": "string",
+              "pattern": "^[a-zA-Z0-9]+([._]?[a-zA-Z0-9]+)*$"
+            },
+            {
+              "$ref": "https://schema.management.azure.com/schemas/common/definitions.json#/definitions/expression"
+            }
+          ],
+          "description": "The administrator username to use for Windows VMs."
         },
         "licenseType": {
           "oneOf": [