Why doesn't routing work with ElasticSearch Bulk API?

Question

I am setting a Bulk request to ElasticSearch and specifying the shard to route to.

But when I run it, the documents get sent to different shards.

Is this a bug i

Answer 1

@Henley Chiu has given the correct answer, I add one detail:

• before es 6.1, you can use _routing or routing field for each individual document when bulk
• after es 6.1(included), you can only use routing

So, you'd better use routing for better future compatibility.