The cluster stats api now returns counts for each node role. The `master_data`, `master_only`, `data_only` and `client` fields have been removed from the response in favour of `master`, `data`, `ingest` and `coordinating_only`. The same node can have multiple roles, hence contribute to multiple roles counts. Every node is implicitly a coordinating node, so whenever a node has no explicit roles, it will be counted as coordinating only.
we currently don't expose this.
This adds the following to the OS section of `_nodes`:
```
"os": {
"name": "Mac OS X",
...
}
```
and the following to the OS section of `_cluster/stats`:
```
"os": {
...
"names": [
{
"name": "Mac OS X",
"count": 1
}
],
...
},
```
Closes#11807
Also changes the response format of that section to:
```
"open_file_descriptors": {
"min": 200,
"max": 346,
"avg": 273
}
```
Closes#4681
Note: this is an aggregate of 3 commits in the 0.90 branch
Mike McCandless
Daniel Mitterdorfer
javanna
Clinton Gormley
Andrey Fadeyev
Boaz Leskes
Martijn van Groningen
spapin
Patrik Ragnarsson