OpenSearch/docs/reference/indices/create-index.asciidoc

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

The Create Index API is used to manually create an index in Elasticsearch.  All documents in Elasticsearch
are stored inside of one index or another.

The most basic command is the following:

[source,js]
--------------------------------------------------
PUT twitter
--------------------------------------------------
// CONSOLE

This create an index named `twitter` with all default setting.

[NOTE]
.Index name limitations
======================================================
There are several limitations to what you can name your index.  The complete list of limitations are:

- Lowercase only
- Cannot include `\`, `/`, `*`, `?`, `"`, `<`, `>`, `|`, ` ` (space character), `,`, `#`
- Indices prior to 7.0 could contain a colon (`:`), but that's been deprecated and won't be supported in 7.0+
- Cannot start with `-`, `_`, `+`
- Cannot be `.` or `..`
- Cannot be longer than 255 bytes (note it is bytes, so multi-byte characters will count towards the 255 limit faster)

======================================================

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

Each index created can have specific settings
associated with it, defined in the body:

[source,js]
--------------------------------------------------
PUT twitter
{
    "settings" : {
        "index" : {
            "number_of_shards" : 3, <1>
            "number_of_replicas" : 2 <2>
        }
    }
}
--------------------------------------------------
// CONSOLE
<1> Default for `number_of_shards` is 1
<2> Default for `number_of_replicas` is 1 (ie one replica for each primary shard)

or more simplified

[source,js]
--------------------------------------------------
PUT twitter
{
    "settings" : {
        "number_of_shards" : 3,
        "number_of_replicas" : 2
    }
}
--------------------------------------------------
// CONSOLE

[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 for providing a mapping definition:

[source,js]
--------------------------------------------------
PUT test
{
    "settings" : {
        "number_of_shards" : 1
    },
    "mappings" : {
        "properties" : {
            "field1" : { "type" : "text" }
        }
    }
}
--------------------------------------------------
// CONSOLE

NOTE: Before 7.0.0, the 'mappings' definition used to include a type name. Although specifying
types in requests is now deprecated, a type can still be provided if the request parameter
include_type_name is set. For more details, please see <<removal-of-types>>.

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

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

[source,js]
--------------------------------------------------
PUT test
{
    "aliases" : {
        "alias_1" : {},
        "alias_2" : {
            "filter" : {
                "term" : {"user" : "kimchy" }
            },
            "routing" : "kimchy"
        }
    }
}
--------------------------------------------------
// CONSOLE

[float]
[[create-index-wait-for-active-shards]]
==== Wait For Active Shards

By default, index creation will only return a response to the client when the primary copies of
each shard have been started, or the request times out. The index creation response will indicate
what happened:

[source,js]
--------------------------------------------------
{
    "acknowledged": true,
    "shards_acknowledged": true,
    "index": "test"
}
--------------------------------------------------
// TESTRESPONSE

`acknowledged` indicates whether the index was successfully created in the cluster, while
`shards_acknowledged` indicates whether the requisite number of shard copies were started for
each shard in the index before timing out. Note that it is still possible for either
`acknowledged` or `shards_acknowledged` to be `false`, but the index creation was successful.
These values simply indicate whether the operation completed before the timeout. If
`acknowledged` is `false`, then we timed out before the cluster state was updated with the
newly created index, but it probably will be created sometime soon. If `shards_acknowledged`
is `false`, then we timed out before the requisite number of shards were started (by default
just the primaries), even if the cluster state was successfully updated to reflect the newly
created index (i.e. `acknowledged=true`).

We can change the default of only waiting for the primary shards to start through the index
setting `index.write.wait_for_active_shards` (note that changing this setting will also affect
the `wait_for_active_shards` value on all subsequent write operations):

[source,js]
--------------------------------------------------
PUT test
{
    "settings": {
        "index.write.wait_for_active_shards": "2"
    }
}
--------------------------------------------------
// CONSOLE
// TEST[skip:requires two nodes]

or through the request parameter `wait_for_active_shards`:

[source,js]
--------------------------------------------------
PUT test?wait_for_active_shards=2
--------------------------------------------------
// CONSOLE
// TEST[skip:requires two nodes]

A detailed explanation of `wait_for_active_shards` and its possible values can be found
<<index-wait-for-active-shards,here>>.