Merge pull request #14787 from MikeRayMSFT/20200430-Enable-External-Scripts

Stage update to enable replica.

Author: Jak-MS

docs/big-data-cluster/machine-learning-services.md

@@ -4,7 +4,7 @@ titleSuffix: SQL Server Big Data Clusters
 description: Learn how you can run Python and R scripts on the master instance of a SQL Server Big Data Clusters with Machine Learning Services.
 author: dphansen
 ms.author: davidph
-ms.date: 11/04/2019
+ms.date: 04/30/2020
 ms.topic: conceptual
 ms.prod: sql
 ms.technology: machine-learning
@@ -31,39 +31,68 @@ RECONFIGURE WITH OVERRIDE
 GO
 ```
 
-## Enable Always On Availability Groups
+You are now ready to run Python and R scripts on the master instance of Big Data Clusters. See the quickstarts under [Next steps](#next-steps) to run your first script.
 
-If you are using SQL Server Big Data Clusters with [Always On Availability Groups](../database-engine/availability-groups/windows/overview-of-always-on-availability-groups-sql-server.md), you need to perform a few extra steps to enable Machine Learning Services.
+>[!NOTE]
+>The configuration setting cannot be set on an availability group listener connection. If Big Data Clusters is deployed with high availability, the set `external scripts enabled` on each replica. See [Enable on cluster with high availability](#enable-on-cluster-with-high-availability).
 
-1. Connect to the master instance and run this statement:
+## Enable on cluster with high availability
 
-    ```sql
-    SELECT @@SERVERNAME
-    ```
+When you [Deploy SQL Server Big Data Cluster with high availability](deployment-high-availability.md), the deployment creates an availability group for the master instance. To enable Machine Learning Services, set `external scripts enabled` on each instance of the availability group. For a Big Data Cluster, you need to run `sp_configure` on each replica of the SQL Server master instance
 
-    Note down the server name. In this example, the server name for the master instance is **master-2**.
+The following section describes how to enable external scripts on each instance.
 
-1. On each replica on the Always On Availability Group in the Big Data Cluster, run these `kubectl` commands:
+### Create an external load balancer for each instance
 
-    ```
-    kubectl -n bdc expose pod master-0 --port=1533 --name=mymaster-0 --type=LoadBalancer
+For each replica on the availability group, create a load balancer to allow you to connect to the instance. 
 
-    kubectl -n bdc expose pod master-1 --port=1533 --name=mymaster-1 --type=LoadBalancer
+`kubectl expose pod <pod-name> --port=<connection port number> --name=<load-balancer-name> --type=LoadBalancer -n <kubernetes namespace>`
 
-    kubectl -n bdc expose pod master-2 --port=1533 --name=mymaster-2 --type=LoadBalancer
-    ```
+The examples in this article use the following values:
 
-    You should see an output similar to this:
-    
-    ```
-    service/mymaster-0 exposed
+- `<pod-name>`: `master-#`
+- `<connection port number>`: `1533`
+- `<load-balancer-name>`: `mymaster-#`
+- `<kubernetes namespace>`: `mssql-cluster`
 
-    service/mymaster-1 exposed
+Update the following script for your environment, and run the commands:
 
-    service/mymaster-2 exposed
-    ```
+```bash
+kubectl expose pod master-0 --port=1533 --name=mymaster-0 --type=LoadBalancer -n mssql-cluster 
+kubectl expose pod master-1 --port=1533 --name=mymaster-1 --type=LoadBalancer -n mssql-cluster
+kubectl expose pod master-2 --port=1533 --name=mymaster-2 --type=LoadBalancer -n mssql-cluster 
+```
+
+`kubectl` returns the following output.
+
+```bash
+service/mymaster-0 exposed
+service/mymaster-1 exposed
+service/mymaster-2 exposed
+```
+
+Each load balancer is a master replica endpoint.
+
+### Enable script execution on each replica
+
+1. Get the IP address for the master replica endpoint.
+
+   The following command returns the external IP address for the replica endpoint. 
+
+   `kubectl get services <load-balancer-name> -n <kubernetes namespace>`
+
+   To get the external IP address for each replica in this scenario, run the following commands:
 
-1. Connect to each master replica endpoint and enable script execution.
+   ```bash
+   kubectl get services mymaster-0 -n mssql-cluster
+   kubectl get services mymaster-1 -n mssql-cluster
+   kubectl get services mymaster-2 -n mssql-cluster
+   ```
+
+   >[!NOTE]
+   > It may take a little time before the external IP address is available. Run the preceding script periodically until each endpoint returns an external IP address.
+
+1. Connect to the master replica endpoint and enable script execution.
 
     Run this statement:
 
@@ -73,7 +102,37 @@ If you are using SQL Server Big Data Clusters with [Always On Availability Group
     GO
     ```
 
-You are now ready to run Python and R scripts on the master instance of Big Data Clusters. See the quickstarts below to run your first script.
+   For example, you can run the preceding command with `sqlcmd`. The following example connects to the master replica endpoint and enables script execution. Update the values in the script with for your environment.
+
+   ```bash
+   sqlcmd -S <IP address>,1533 -U <user name> -P <password> -Q "EXEC sp_configure 'external scripts enabled', 1; RECONFIGURE WITH OVERRIDE;"
+   ```
+
+   Repeat the step for each replica.
+
+### Demonstration
+
+The following image demonstrates this process.
+
+:::image type="content" source="media/machine-learning-services/example-kube-enable-scripts.png" alt-text="demonstrate-configure-external-script-availability-group":::
+
+You are now ready to run Python and R scripts on the master instance of Big Data Clusters. See the quickstarts under [Next steps](#next-steps) to run your first script.
+
+### Delete the master replica endpoints
+
+On the Kubernetes cluster, delete the endpoint for each replica. The endpoint is exposed in Kubernetes as a load-balancing service.
+
+The following command deletes load-balancing service.
+
+`kubectl delete svc <load-balancer-name> -n mssql-cluster`
+
+For the examples in this article, run the following commands.
+
+```bash
+kubectl delete svc mymaster-0 -n mssql-cluster
+kubectl delete svc mymaster-1 -n mssql-cluster
+kubectl delete svc mymaster-2 -n mssql-cluster
+```
 
 ## Next steps