Elasticsearch(6.7.1) Index Lifecycle Management Policy Creation

I am trying to experiment with Elasticsearch ILM feature. All the documentation and example show how to create ILM Policy, using REST API or using Kibana GUI.

I want to ask is there a way to provide ILM policy Json string in some config file, so that the policy is created automatically, when Elasticserach starts(I am running Elasticserach 6.7.1).

There currently isn't a way to have a policy automatically set up when ES starts, you'll have to add it via the API externally (similar to adding templates).