How to display the ElasticSearch schema of my BusinessData

you should be able to retrieve it from a running Designer or Engine via: http://localhost:19200/ivy.businessdata

mine looks like this. After storing a 'Person' with two string fields (firstname, lastname)

Find the right instance

If the ElasticSearch is not responding under the default URI (http://localhost:19200), where could it be?

• Not started: ElasticSearch could yet not be running as none of your project has yet defined any BusinessData nor run any queries against the BusinessDataRepo API. The ElasticSearch instance is only started when it is really needed - lazy.
• Random port: ElasticSearch may runs under a different port as multiple Designers and Engines are running on the same host. You can detect running instances then by opening JVisualVM which you can find in the JDK/bin directory. Open the org.elasticsearch.bootstrap.IvyElasticsearchStarterStopper and inspect the JVM arguments. Under -Des.http.port=XXXX you will see the port where the instance is accessible. It is also possible that you find multiple instances of the IvyElasticsearchStarterStopper here...
• Fixed host+port: In a productive environment you may not like that ElasticSearch instance runs on a random port. Therefore you are free to run your own instance on a fixed port and configure it with a System Property for the Axon.ivy Engine: see http://developer.axonivy.com/releases/ivy/6.6.latest/documents/EngineGuideHtml/installation.html#installation-elasticsearch