demonstrate consuming external services
over TCP. You will use the <a href=/v1.22/docs/examples/bookinfo/>Istio Bookinfo sample application</a>, the version in which the book
ratings data is persisted in a MySQL database. You deploy this database outside the cluster and configure the
<em>ratings</em> microservice to use it. You define a
<a href=/v1.22/docs/reference/config/networking/service-entry/>Service Entry</a> to allow the in-mesh applications to
access the external database.</p><h2 id=bookinfo-sample