[[cat-nodeattrs]]
== cat nodeattrs

The `nodeattrs` command shows custom node attributes.
For example:

[source,js]
--------------------------------------------------
GET /_cat/nodeattrs?v
--------------------------------------------------
// CONSOLE
// TEST[s/\?v/\?v&s=node,attr/]
// Sort the resulting attributes so we can assert on them more easily

Could look like:

[source,txt]
--------------------------------------------------
node    host      ip        attr     value
...
node-0 127.0.0.1 127.0.0.1 testattr test
...
--------------------------------------------------
// TESTRESPONSE[s/\.\.\.\n$/\n(.+ xpack\\.installed true\n)?\n/]
// TESTRESPONSE[s/\.\.\.\n/(.+ ml\\..+\n)*/ _cat]
// If xpack is not installed then neither ... with match anything
// If xpack is installed then the first ... contains ml attributes
// and the second contains xpack.installed=true

The first few columns (`node`, `host`, `ip`) give you basic info per node
and the `attr` and `value` columns give you the custom node attributes,
one per line.

[float]
=== Columns

Below is an exhaustive list of the existing headers that can be
passed to `nodeattrs?h=` to retrieve the relevant details in ordered
columns.  If no headers are specified, then those marked to Appear
by Default will appear. If any header is specified, then the defaults
are not used.

Aliases can be used in place of the full header name for brevity.
Columns appear in the order that they are listed below unless a
different order is specified (e.g., `h=attr,value` versus `h=value,attr`).

When specifying headers, the headers are not placed in the output
by default.  To have the headers appear in the output, use verbose
mode (`v`). The header name will match the supplied value (e.g.,
`pid` versus `p`).  For example:

[source,js]
--------------------------------------------------
GET /_cat/nodeattrs?v&h=name,pid,attr,value
--------------------------------------------------
// CONSOLE
// TEST[s/,value/,value&s=node,attr/]
// Sort the resulting attributes so we can assert on them more easily

Might look like:

[source,txt]
--------------------------------------------------
name    pid   attr     value
...
node-0 19566 testattr test
...
--------------------------------------------------
// TESTRESPONSE[s/19566/\\d*/]
// TESTRESPONSE[s/\.\.\.\n$/\n(.+ xpack\\.installed true\n)?\n/]
// TESTRESPONSE[s/\.\.\.\n/(.+ ml\\..+\n)*/ _cat]
// If xpack is not installed then neither ... with match anything
// If xpack is installed then the first ... contains ml attributes
// and the second contains xpack.installed=true

[cols="<,<,<,<,<",options="header",subs="normal"]
|=======================================================================
|Header |Alias |Appear by Default |Description |Example
|`node`|`name`|Yes|Name of the node|DKDM97B
|`id` |`nodeId` |No |Unique node ID |k0zy
|`pid` |`p` |No |Process ID |13061
|`host` |`h` |Yes |Host name |n1
|`ip` |`i` |Yes |IP address |127.0.1.1
|`port` |`po` |No |Bound transport port |9300
|`attr` | `attr.name` | Yes | Attribute name | rack
|`value` | `attr.value` | Yes | Attribute value | rack123
|=======================================================================