History

Lee Hinman 80ab366de4 Add API to explain why a shard is or isn't assigned This adds a new `/_cluster/allocation/explain` API that explains why a shard can or cannot be allocated to nodes in the cluster. Additionally, it will show where the master desires to put the shard, according to the `ShardsAllocator`. It looks like this: ``` GET /_cluster/allocation/explain?pretty { "index": "only-foo", "shard": 0, "primary": false } ``` Though, you can optionally send an empty body, which means "explain the allocation for the first unassigned shard you find". The output when a shard is unassigned looks like this: ``` { "shard" : { "index" : "only-foo", "index_uuid" : "KnW0-zELRs6PK84l0r38ZA", "id" : 0, "primary" : false }, "assigned" : false, "unassigned_info" : { "reason" : "INDEX_CREATED", "at" : "2016-03-22T20:04:23.620Z" }, "nodes" : { "V-Spi0AyRZ6ZvKbaI3691w" : { "node_name" : "Susan Storm", "node_attributes" : { "bar" : "baz" }, "final_decision" : "NO", "weight" : 0.06666675, "decisions" : [ { "decider" : "filter", "decision" : "NO", "explanation" : "node does not match index include filters [foo:\"bar\"]" } ] }, "Qc6VL8c5RWaw1qXZ0Rg57g" : { "node_name" : "Slipstream", "node_attributes" : { "bar" : "baz", "foo" : "bar" }, "final_decision" : "NO", "weight" : -1.3833332, "decisions" : [ { "decider" : "same_shard", "decision" : "NO", "explanation" : "the shard cannot be allocated on the same node id [Qc6VL8c5RWaw1qXZ0Rg57g] on which it already exists" } ] }, "PzdyMZGXQdGhqTJHF_hGgA" : { "node_name" : "The Symbiote", "node_attributes" : { }, "final_decision" : "NO", "weight" : 2.3166666, "decisions" : [ { "decider" : "filter", "decision" : "NO", "explanation" : "node does not match index include filters [foo:\"bar\"]" } ] } } } ``` And when the shard is assigned, the output looks like: ``` { "shard" : { "index" : "only-foo", "index_uuid" : "KnW0-zELRs6PK84l0r38ZA", "id" : 0, "primary" : true }, "assigned" : true, "assigned_node_id" : "Qc6VL8c5RWaw1qXZ0Rg57g", "nodes" : { "V-Spi0AyRZ6ZvKbaI3691w" : { "node_name" : "Susan Storm", "node_attributes" : { "bar" : "baz" }, "final_decision" : "NO", "weight" : 1.4499999, "decisions" : [ { "decider" : "filter", "decision" : "NO", "explanation" : "node does not match index include filters [foo:\"bar\"]" } ] }, "Qc6VL8c5RWaw1qXZ0Rg57g" : { "node_name" : "Slipstream", "node_attributes" : { "bar" : "baz", "foo" : "bar" }, "final_decision" : "CURRENTLY_ASSIGNED", "weight" : 0.0, "decisions" : [ { "decider" : "same_shard", "decision" : "NO", "explanation" : "the shard cannot be allocated on the same node id [Qc6VL8c5RWaw1qXZ0Rg57g] on which it already exists" } ] }, "PzdyMZGXQdGhqTJHF_hGgA" : { "node_name" : "The Symbiote", "node_attributes" : { }, "final_decision" : "NO", "weight" : 3.6999998, "decisions" : [ { "decider" : "filter", "decision" : "NO", "explanation" : "node does not match index include filters [foo:\"bar\"]" } ] } } } ``` Only "NO" decisions are returned by default, but all decisions can be shown by specifying the `?include_yes_decisions=true` parameter in the request. Resolves #14593		2016-03-28 15:21:02 -06:00
..
src/main/resources/rest-api-spec	Add API to explain why a shard is or isn't assigned	2016-03-28 15:21:02 -06:00
.gitignore	Initial commit (blank repository)	2013-05-23 17:56:22 +02:00
README.markdown	[API] changed all the links in json specs to the new site	2015-03-24 17:30:32 +01:00
build.gradle	Switch build system to Gradle	2015-10-29 11:40:19 -07:00

README.markdown

Elasticsearch REST API JSON specification

This repository contains a collection of JSON files which describe the Elasticsearch HTTP API.

Their purpose is to formalize and standardize the API, to facilitate development of libraries and integrations.

Example for the "Create Index" API:

{
  "indices.create": {
    "documentation": "http://www.elastic.co/guide/en/elasticsearch/reference/master/indices-create-index.html",
    "methods": ["PUT", "POST"],
    "url": {
      "path": "/{index}",
      "paths": ["/{index}"],
      "parts": {
        "index": {
          "type" : "string",
          "required" : true,
          "description" : "The name of the index"
        }
      },
      "params": {
        "timeout": {
          "type" : "time",
          "description" : "Explicit operation timeout"
        }
      }
    },
    "body": {
      "description" : "The configuration for the index (`settings` and `mappings`)"
    }
  }
}

The specification contains:

The name of the API (indices.create), which usually corresponds to the client calls
Link to the documentation at http://elastic.co
List of HTTP methods for the endpoint
URL specification: path, parts, parameters
Whether body is allowed for the endpoint or not and its description

The methods and url.paths elements list all possible HTTP methods and URLs for the endpoint; it is the responsibility of the developer to use this information for a sensible API on the target platform.

Utilities

The repository contains some utilities in the utils directory:

The thor api:generate:spec will generate the basic JSON specification from Java source code
The thor api:generate:code generates Ruby source code and tests from the specs, and can be extended to generate assets in another programming language

Run bundle install and then thor list in the utils folder.

The full command to generate the api spec is:

thor api:spec:generate --output=myfolder --elasticsearch=/path/to/es

License

This software is licensed under the Apache License, version 2 ("ALv2").