diff --git a/azurerm/internal/services/containers/kubernetes_cluster_node_pool_resource.go b/azurerm/internal/services/containers/kubernetes_cluster_node_pool_resource.go
index fbd4243562dac..f8a2073479cc4 100644
--- a/azurerm/internal/services/containers/kubernetes_cluster_node_pool_resource.go
+++ b/azurerm/internal/services/containers/kubernetes_cluster_node_pool_resource.go
@@ -405,7 +405,7 @@ func resourceKubernetesClusterNodePoolCreate(d *schema.ResourceData, meta interf
 	}
 
 	if linuxOSConfig := d.Get("linux_os_config").([]interface{}); len(linuxOSConfig) > 0 {
-		if osType != string(containerservice.Linux) {
+		if osType != string(containerservice.OSTypeLinux) {
 			return fmt.Errorf("`linux_os_config` can only be configured when `os_type` is set to `linux`")
 		}
 		linuxOSConfig, err := expandAgentPoolLinuxOSConfig(linuxOSConfig)
diff --git a/azurerm/internal/services/containers/kubernetes_nodepool.go b/azurerm/internal/services/containers/kubernetes_nodepool.go
index c9868c65e4358..aec99d6c6d4d8 100644
--- a/azurerm/internal/services/containers/kubernetes_nodepool.go
+++ b/azurerm/internal/services/containers/kubernetes_nodepool.go
@@ -705,7 +705,7 @@ func ExpandDefaultNodePool(d *schema.ResourceData) (*[]containerservice.ManagedC
 }
 
 func expandAgentPoolKubeletConfig(input []interface{}) *containerservice.KubeletConfig {
-	if len(input) == 0 {
+	if len(input) == 0 || input[0] == nil {
 		return nil
 	}
 
@@ -746,7 +746,7 @@ func expandAgentPoolKubeletConfig(input []interface{}) *containerservice.Kubelet
 }
 
 func expandAgentPoolLinuxOSConfig(input []interface{}) (*containerservice.LinuxOSConfig, error) {
-	if len(input) == 0 {
+	if len(input) == 0 || input[0] == nil {
 		return nil, nil
 	}
 	raw := input[0].(map[string]interface{})
@@ -771,7 +771,7 @@ func expandAgentPoolLinuxOSConfig(input []interface{}) (*containerservice.LinuxO
 }
 
 func expandAgentPoolSysctlConfig(input []interface{}) (*containerservice.SysctlConfig, error) {
-	if len(input) == 0 {
+	if len(input) == 0 || input[0] == nil {
 		return nil, nil
 	}
 	raw := input[0].(map[string]interface{})
diff --git a/website/docs/r/kubernetes_cluster.html.markdown b/website/docs/r/kubernetes_cluster.html.markdown
index d37f09ec96baa..5bd218270c2ef 100644
--- a/website/docs/r/kubernetes_cluster.html.markdown
+++ b/website/docs/r/kubernetes_cluster.html.markdown
@@ -522,6 +522,8 @@ A `ssh_key` block supports the following:
 
 A `sysctl_config` block supports the following:
 
+~> For more information, please refer to [Linux Kernel Doc](https://www.kernel.org/doc/html/latest/admin-guide/sysctl/index.html).
+
 * `fs_aio_max_nr` - (Optional) The sysctl setting fs.aio-max-nr. Must be between `65536` and `6553500`. Changing this forces a new resource to be created.
 
 * `fs_file_max` - (Optional) The sysctl setting fs.file-max. Must be between `8192` and `12000500`. Changing this forces a new resource to be created.