Kibana upgrade fails because of rest.action.multi.allow_explicit_index

Elastic Stack Kibana
1

When upgrading ES and Kibana from 5.6 to 6.7, Kibana does not start up, because the migration of configuration index (.kibana) fails. The reason is rest.action.multi.allow_explicit_index = false setting.

I found a fix of this, which is removing the index name from the index api payload and putting in the URL, i.e. removing this line : https://github.com/elastic/kibana/blob/59e632afe5423c872411c6b2885c410e353e507c/src/core/server/saved_objects/migrations/core/elastic_index.ts#L118, and adding index: index, between lines 113 and 114. I verified this fix works fine for me, but I wonder if there is any special reason the index name is kept in the payload, not in the URL.

2

It shouldn't be necessary to pass the index in the url since the index is also passed in the body of the _bulk request.
From the Bulk documentation

The endpoints are /_bulk , /{index}/_bulk , and {index}/{type}/_bulk . When the index or the index/type are provided, they will be used by default on bulk items that don’t provide them explicitly.

I'm not quite sure why it failed for you though but I'm glad you got it working!

3

I think the documentation of that setting clearly says why it is necessary. My question was different though, so it's still unanswered.