Node attributes in _cat/nodes

[suyograo]

It would be useful if _cat/nodes can output node attributes like rack_id, aws_zone and other user defined attributes. If users have a large cluster with nodes in multiple AZ's or racks, it would be great to have this info in _cat/nodes to understand the topology.

Even if not displayed by default, we could allow users to pass in nodes?h=rack_id

Example:

host                     ip          heap.percent ram.percent load node.role master name rack_id
Suyogs-MacBook-Pro.local 192.168.1.6            0                  d         *      Jann rack_1
Suyogs-MacBook-Pro.local 192.168.1.6            0                  d         *      Hoder rack_2

[drewr]

Sorry to just be noticing this, but I caught the email from @metadave's PR.

This has a similar problem to _cat/fielddata that #10249 is meant to address, namely that column names should never be dynamic. We always denormalize instead. See _cat/shards or _cat/segments for example.

In this case, since node attributes are such a small part of a node identity, I wonder if it doesn't make sense to have a new API, _cat/nodeattrs or somesuch?

% GET /_cat/nodeattrs
node    attr.name     attr.value
n1      zone          zone2323
n2      zone          zone8282

The default could have more info, maybe host and port.

[bookshelfdave]

+1, I like how your GET /_cat/nodeattrs example looks

[bookshelfdave]

Node attributes are available in _cat/nodeattrs via #12534