Elasticsearch reroute move command: remote_transport_exception Error

[stefano1 (stefano)]

Good Morning All,

I have to balance the cluster occupation of the ES cluster, our cluster is composed by 11 servers and i am a beginner in Elasticsearch software. I would to move an index with primary shard to another machine with more disk space. The only way I found is to execute reroute and move command but, unfortunately, does not work giving me error.

This is the syntax of my Curl reroute command:

curl -XPOST 'ip_address:port/_cluster/reroute' 
  -d '{"commands" : [ {"move" :{"index" : "index", "shard" : 2,"from_node" : "node1", "to_node" : "node2"}}]}'

I was expecting a success move of the index and the shard but, unfortunately, this is the error message found in the log:

[2019-05-24T09:53:55,189][DEBUG][o.e.a.a.c.r.TransportClusterRerouteAction] [ithprodXX-elk] failed to perform [cluster_reroute (api)]
java.lang.NullPointerException: null

In the output of the command I was expecting like "moved to node X" but, unfortunately, I have the below output:

{"error":{"root_cause":[{"type":"remote_transport_exception","reason":"[ithprod05-elk][10.79.207.69:9300][cluster:admin/reroute]"}]
,"type":"null_pointer_exception","reason":null},"status":500}

Does somebody know what it should be the root cause of the issue and how to fix it?
In the case I've not been clear and you need more details do not hesitate to contact me with more comments for more clarifications

Many thanks in advance

Stefano

[DavidTurner]

@stefano1

this is the error message found in the log:

This one-line message should have been followed by a whole stack trace, without which there's not a lot we can do here. Can you share the whole message?

Also, it'd be very helpful to know which version you are on. We fixed a NullPointerException in this area in #28886 (v6.3.0) so maybe it's that?