GET _nodes/master:false does not work

[linker-c]

Describe the feature:

Elasticsearch version (bin/elasticsearch --version): 6.1.1

Plugins installed: [None]

JVM version (java -version): Not applicable

OS version (uname -a if on a Unix-like system): Not applicable

Description of the problem including expected versus actual behavior:
There is a bug where searching for a node type == false returns nothing.
Master node type is just one example. data:false is also not working.

What I'm trying to do is to discover just the ingest nodes for writing, and only coordinator nodes for reading.
Then I encountered this issue.

Steps to reproduce:

From kibana Dev Tools Console

1. GET /_nodes/master:true returns the master nodes in my cluster
2. GET /_nodes/master:false returns no nodes.

Provide logs (if relevant):
GET /_nodes/master:true returns the following 3 nodes

GET /_nodes/master:false returns nothing

GET /_cat/nodes?v // I have total of 9 nodes in the cluster

[jasontedor]

This feature works like this: if you specify role:true, it is additive (it adds nodes matching that role to the set of nodes that will be returned) and if you specify role:false, it is subtractive (it removes nodes matching that role from the set of nodes already collected). Order matters. So, to see all data nodes that are not master-eligible nodes: data:true,master:false. To see all master-eligible nodes that are not data nodes: master:false,data:true.

I hope this helps.

[linker-c]

Thanks @jasontedor . That's more clear than the official document would state.
How do I find coordinator nodes that's not data nor master?

[jasontedor]

How do I find coordinator nodes that's not data nor master?

I do not think that is possible with the existing functionality, sorry.

[jasontedor]

@linker-mist I have integrated #28971 which will make it possible to do /_nodes/_all,data:false,master:false to obtain all coordinating nodes that are not data nodes and not master-eligible.

[XANi]

@jasontedor Could you add your explanation to docs ?

https://www.elastic.co/guide/en/elasticsearch/reference/6.2/cluster.html#cluster-nodes page says nothing about it and it is a really useful function

[DaveCTurner]

Since #30313 you can say /_nodes/coordinating_only:true to obtain the coordinating-only nodes, and /_nodes/ingest:true yields the ingest nodes. Updated docs for this are on their way in #30468. This'll be in 6.4.0.