We run rspec tests after provisioning to confirm Elasticsearch is configured properly. We do not explicitly set the value for index.number_of_replicas in the config, so it should default to 1. For all indices created by us or Marvel, that is what we observe. But I noticed that the .scripts index is always created with 0 replicas.
Is this correct behavior? It seems like it should follow the global setting unless there is a separate setting specifically for .scripts that I'm not aware of.
If it is correct behavior, a) it should be documented, and b) why? It seems like the fact that .scripts reports one shard and no replicas means that there will always be one node that can take down our cluster, as all our searches use templates stored in the .scripts index.
Currently I have to special-case our cluster validating logic to allow "number_of_replicas": "0" for .scripts and 1 for everything else. Any guidance on whether or not this is a bug in Elasticsearch, whether I should explicitly set number_of_replicas to 1 via Index Update API to ensure cluster availability if I lose my .scripts node, etc. would be greatly appreciated.
Thanks,
-joel