Search indexing fails for certain repositories when using AWS Elasticsearch

Summary

When using AWS Elasticsearch Service, Bitbucket Server's indexing may fail spontaneously with IndexException's

Environment

• Bitbucket Server 4.10 in EC2 using AWS Request signing for Elasticsearch
• AWS Elasticsearch

Steps to Reproduce

1. Launch Bitbucket with a large dataset in AWS using the Bitbucket Data Center CloudFormation template

Expected Results

There are no indexing errors

Actual Results

The below exception is logged in the atlassian-bitbucket.log file:

 c.a.b.s.i.i.e.DefaultIndexEventWorker Indexing - Failed for repository SHELL/wifi-password-10 (id: 2) with error: Indexing for repository with id 2 failed and should be retried
com.atlassian.bitbucket.search.indexer.exceptions.IndexException: Indexing for repository with id 2 failed and should be retried

Workaround

Disable AWS request signing and configure an IP based Elasticsearch access policy.