I just updated AWS Elasticsearch from version 5.6 to 6.8. And there is an Auto-Tune feature tab appeared in the Console. But it looks like does not work and shows only "Error" in front of Auto-Tune and nothing else.
After enabling Auto-Tune it show as Enabled, but after page reloaded changes to Error status back.
Is any solutions to fix this or additional ways to get more detailed error message?
Since I did not find any solution, I raised an AWS support ticket and got the answer. This issue appears when the ES cluster migrating from an Elastic Search version which did not support Auto-Tune to one that does (in my case 5.6 to 6.8).
As a solution, the AWS service team manually deployed Auto-Tune agent on cluster and it took about a day. After that I can enable or disable Auto-Tune as well.
BTW, new domains creates already with Auto-Tune feature enabled, so in the case of a new cluster, you should not face it.