Merge pull request aws#178 from awslabs/vrkhare-patch-2

resolving the Redshift DNS name to a private IP

Author: djarpin

advanced_functionality/working_with_redshift_data/working_with_redshift_data.ipynb

@@ -27,6 +27,10 @@
     "1. Preload that cluster with data from the [iris data set](https://archive.ics.uci.edu/ml/datasets/iris) in a table named public.irisdata.\n",
     "1. Update the credential file (`redshift_creds_template.json.nogit`) file with the appropriate information.\n",
     "\n",
+    "Also, note that this Notebook instance needs to resolve to a private IP when connecting to the Redshift instance. There are two ways to resolve the Redshift DNS name to a private IP:\n",
+    "1. The Redshift cluster is not publicly accessible so by default it will resolve to private IP.\n",
+    "1. The Redshift cluster is publicly accessible and has an EIP associated with it but when accessed from within a VPC, it should resolve to private IP of the Redshift cluster. This is possible by setting following two VPC attributes to yes: DNS resolution and DNS hostnames. For instructions on setting that up, see Redshift public docs on [Managing Clusters in an Amazon Virtual Private Cloud (VPC)](https://docs.aws.amazon.com/redshift/latest/mgmt/managing-clusters-vpc.html).\n",
+    "\n",
     "### Notebook Setup\n",
     "Let's start by installing `psycopg2`, a PostgreSQL database adapter for the Python, adding a few imports and specifying a few configs. "
    ]