Bug: Docker image has problems starting the ponymail index shards

This appears to be because the default number of replicas is set to 1 when creating an index.

A possible solution is to add the following to /etc/elasticsearch/elasticsearch.yml

index.number_of_replicas: 0

It might also be worth adding the following so it runs better on smaller test systems:

index.number_of_shards: 1

The changes need to be made before starting the elasticsearch service

Start by locating how the Docker image creates or configures /etc/elasticsearch/elasticsearch.yml, then verify the ordering relative to starting the Elasticsearch service. Done means the image applies the proposed shard and replica settings before startup and the Ponymail index shards start successfully on a small test system.

Written by the indexing model from the issue text.