[[indices-create-index]]
== Create Index

The create index API allows to instantiate an index. Elasticsearch
provides support for multiple indices, including executing operations
across several indices.

[float]
[[create-index-settings]]
=== Index Settings

Each index created can have specific settings
associated with it.

[source,js]
--------------------------------------------------
$ curl -XPUT 'http://localhost:9200/twitter/' -d '{
    "settings" : {
        "index" : {
            "number_of_shards" : 3, <1>
            "number_of_replicas" : 2 <2>
        }
    }
}'
--------------------------------------------------
<1> Default for `number_of_shards` is 5
<2> Default for `number_of_replicas` is 1 (ie one replica for each primary shard)

The above second curl example shows how an index called `twitter` can be
created with specific settings for it using http://www.yaml.org[YAML].
In this case, creating an index with 3 shards, each with 2 replicas. The
index settings can also be defined with http://www.json.org[JSON]:

[source,js]
--------------------------------------------------
$ curl -XPUT 'http://localhost:9200/twitter/' -d '{
    "settings" : {
        "index" : {
            "number_of_shards" : 3,
            "number_of_replicas" : 2
        }
    }
}'
--------------------------------------------------

or more simplified

[source,js]
--------------------------------------------------
$ curl -XPUT 'http://localhost:9200/twitter/' -d '{
    "settings" : {
        "number_of_shards" : 3,
        "number_of_replicas" : 2
    }
}'
--------------------------------------------------

[NOTE]
You do not have to explicitly specify `index` section inside the
`settings` section.

For more information regarding all the different index level settings
that can be set when creating an index, please check the
<<index-modules,index modules>> section.


[float]
[[mappings]]
=== Mappings

The create index API allows to provide a set of one or more mappings:

[source,js]
--------------------------------------------------
curl -XPOST localhost:9200/test -d '{
    "settings" : {
        "number_of_shards" : 1
    },
    "mappings" : {
        "type1" : {
            "properties" : {
                "field1" : { "type" : "text" }
            }
        }
    }
}'
--------------------------------------------------

[float]
[[create-index-aliases]]
=== Aliases

The create index API allows also to provide a set of <<indices-aliases,aliases>>:

[source,js]
--------------------------------------------------
curl -XPUT localhost:9200/test -d '{
    "aliases" : {
        "alias_1" : {},
        "alias_2" : {
            "filter" : {
                "term" : {"user" : "kimchy" }
            },
            "routing" : "kimchy"
        }
    }
}'
--------------------------------------------------

[float]
=== Creation Date

When an index is created, a timestamp is stored in the index metadata for the creation date.  By 
default this is automatically generated but it can also be specified using the 
`creation_date` parameter on the create index API:

[source,js]
--------------------------------------------------
curl -XPUT localhost:9200/test -d '{
    "creation_date" : 1407751337000 <1>
}'
--------------------------------------------------

<1> `creation_date` is set using epoch time in milliseconds.