This page from ES 2.x documentation suggests that it is possible to use ElasticSearch as a global locking source of truth. Is it still reliable in 5.x? As I understand it, it shouldn't be a problem, but I wonder why this documentation wasn't ported to 5.x and 6.x? Has something changed in the documents API acidity?
(To give you the bigger picture, I want to implement an advisory lock in my app. It would be much easier if I could rely on ElasticSearch to do this.)