It seems each new filebeat version creates its own mapping template and ilm policy. i had to manually update ilm policy to add delete phase. but for each new version a new ilm policy is created with default sections (without delete phase) and then has to be updated manually. is there a more easier approach for this ?
Hi @Jathin 
I'm not an expert in ILM but when you usually apply a Policy to an index template which should look like filebeat-* so no matter which version you are using, it will cover indices starting with filebeat-*. Some extra info: https://www.elastic.co/guide/en/elasticsearch/reference/current/applying-policy-to-template.html
I hope this helps
But it seems filebeat create templates for each version and they map to a ilm policy with version in name and that ilm policy does not have delete phase.. also you can just have one policy per index.