A few weeks ago, I had a two-node Elasticsearch cluster (evidently my mistake...though IDK why AWS can operate high availability two-node transaction RDS clusters no problem but not ES).
One node went down, only manual intervention by AWS support could fix it, automatic backups were completely inaccessible (since they rely on the cluster being up? ... WTF), and it took many hours for support to reset the cluster.
I eventually just "screw it," and spent a couple rebuilding the cluster from scratch.