[role="xpack"]
[[set-up-a-data-stream]]
== Set up a data stream

To set up a data stream, follow these steps:

* <<create-index-lifecycle-policy>>
* <<create-component-templates>>
* <<create-index-template>>
* <<create-data-stream>>
* <<secure-data-stream>>

You can also <<convert-index-alias-to-data-stream,convert an index alias to
a data stream>>.

IMPORTANT: If you use {fleet} or {agent}, skip this tutorial. {fleet} and
{agent} set up data streams for you. See {fleet}'s
{fleet-guide}/data-streams.html[data streams] documentation.

[discrete]
[[create-index-lifecycle-policy]]
=== Step 1. Create an index lifecycle policy

While optional, we recommend using {ilm-init} to automate the management of your
data stream's backing indices. {ilm-init} requires an index lifecycle policy.

To create an index lifecycle policy in {kib}, open the main menu and go to
*Stack Management > Index Lifecycle Policies*. Click *Create policy*.

You can also use the <<ilm-put-lifecycle,create lifecycle policy API>>.

// tag::ilm-policy-api-ex[]
[source,console]
----
PUT _ilm/policy/my-lifecycle-policy
{
  "policy": {
    "phases": {
      "hot": {
        "actions": {
          "rollover": {
            "max_primary_shard_size": "50gb"
          }
        }
      },
      "warm": {
        "min_age": "30d",
        "actions": {
          "shrink": {
            "number_of_shards": 1
          },
          "forcemerge": {
            "max_num_segments": 1
          }
        }
      },
      "cold": {
        "min_age": "60d",
        "actions": {
          "searchable_snapshot": {
            "snapshot_repository": "found-snapshots"
          }
        }
      },
      "frozen": {
        "min_age": "90d",
        "actions": {
          "searchable_snapshot": {
            "snapshot_repository": "found-snapshots"
          }
        }
      },
      "delete": {
        "min_age": "735d",
        "actions": {
          "delete": {}
        }
      }
    }
  }
}
----
// end::ilm-policy-api-ex[]

[discrete]
[[create-component-templates]]
=== Step 2. Create component templates

// tag::ds-create-component-templates[]
A data stream requires a matching index template. In most cases, you compose
this index template using one or more component templates. You typically use
separate component templates for mappings and index settings. This lets you
reuse the component templates in multiple index templates.

When creating your component templates, include:

* A <<date,`date`>> or <<date_nanos,`date_nanos`>> mapping for the `@timestamp`
field. If you don't specify a mapping, {es} maps `@timestamp` as a `date` field
with default options.

* Your lifecycle policy in the `index.lifecycle.name` index setting.

[TIP]
====
Use the {ecs-ref}[Elastic Common Schema (ECS)] when mapping your fields. ECS
fields integrate with several {stack} features by default.

If you're unsure how to map your fields, use <<runtime-search-request,runtime
fields>> to extract fields from <<mapping-unstructured-content,unstructured
content>> at search time. For example, you can index a log message to a
`wildcard` field and later extract IP addresses and other data from this field
during a search.
====

To create a component template in {kib}, open the main menu and go to *Stack
Management > Index Management*. In the *Index Templates* view, click *Create
component template*.

You can also use the <<indices-component-template,create component template
API>>.

[source,console]
----
# Creates a component template for mappings
PUT _component_template/my-mappings
{
  "template": {
    "mappings": {
      "properties": {
        "@timestamp": {
          "type": "date",
          "format": "date_optional_time||epoch_millis"
        },
        "message": {
          "type": "wildcard"
        }
      }
    }
  },
  "_meta": {
    "description": "Mappings for @timestamp and message fields",
    "my-custom-meta-field": "More arbitrary metadata"
  }
}

# Creates a component template for index settings
PUT _component_template/my-settings
{
  "template": {
    "settings": {
      "index.lifecycle.name": "my-lifecycle-policy"
    }
  },
  "_meta": {
    "description": "Settings for ILM",
    "my-custom-meta-field": "More arbitrary metadata"
  }
}
----
// TEST[continued]
// end::ds-create-component-templates[]

[discrete]
[[create-index-template]]
=== Step 3. Create an index template

// tag::ds-create-index-template[]
Use your component templates to create an index template. Specify:

* One or more index patterns that match the data stream's name. We recommend
using our {fleet-guide}/data-streams.html#data-streams-naming-scheme[data stream
naming scheme].

* That the template is data stream enabled.

* Any component templates that contain your mappings and index settings.

* A priority higher than `200` to avoid collisions with built-in templates.
See <<avoid-index-pattern-collisions>>.

To create an index template in {kib}, open the main menu and go to *Stack
Management > Index Management*. In the *Index Templates* view, click *Create
template*.

You can also use the <<indices-put-template,create index template API>>.
Include the `data_stream` object to enable data streams.

[source,console]
----
PUT _index_template/my-index-template
{
  "index_patterns": ["my-data-stream*"],
  "data_stream": { },
  "composed_of": [ "my-mappings", "my-settings" ],
  "priority": 500,
  "_meta": {
    "description": "Template for my time series data",
    "my-custom-meta-field": "More arbitrary metadata"
  }
}
----
// TEST[continued]
// end::ds-create-index-template[]

[discrete]
[[create-data-stream]]
=== Step 4. Create the data stream

// tag::ds-create-data-stream[]
<<add-documents-to-a-data-stream,Indexing requests>> add documents to a data
stream. These requests must use an `op_type` of `create`. Documents must include
a `@timestamp` field.

To automatically create your data stream, submit an indexing request that
targets the stream's name. This name must match one of your index template's
index patterns.

[source,console]
----
PUT my-data-stream/_bulk
{ "create":{ } }
{ "@timestamp": "2099-05-06T16:21:15.000Z", "message": "192.0.2.42 - - [06/May/2099:16:21:15 +0000] \"GET /images/bg.jpg HTTP/1.0\" 200 24736" }
{ "create":{ } }
{ "@timestamp": "2099-05-06T16:25:42.000Z", "message": "192.0.2.255 - - [06/May/2099:16:25:42 +0000] \"GET /favicon.ico HTTP/1.0\" 200 3638" }

POST my-data-stream/_doc
{
  "@timestamp": "2099-05-06T16:21:15.000Z",
  "message": "192.0.2.42 - - [06/May/2099:16:21:15 +0000] \"GET /images/bg.jpg HTTP/1.0\" 200 24736"
}
----
// TEST[continued]
// end::ds-create-data-stream[]

You can also manually create the stream using the
<<indices-create-data-stream,create data stream API>>. The stream's name must
still match one of your template's index patterns.

[source,console]
----
PUT _data_stream/my-data-stream
----
// TEST[continued]
// TEST[s/my-data-stream/my-data-stream-alt/]

[discrete]
[[secure-data-stream]]
=== Step 5. Secure the data stream

include::{xes-repo-dir}/security/authorization/alias-privileges.asciidoc[tag=data-stream-security]

For an example, see <<data-stream-privileges>>.

[discrete]
[[convert-index-alias-to-data-stream]]
=== Convert an index alias to a data stream

// tag::time-series-alias-tip[]
Prior to {es} 7.9, you'd typically use an
<<manage-time-series-data-without-data-streams,index alias with a write index>>
to manage time series data. Data streams replace this functionality, require
less maintenance, and automatically integrate with <<data-tiers,data tiers>>.
// end::time-series-alias-tip[]

To convert an index alias with a write index to a data stream with the same
name, use the <<indices-migrate-to-data-stream,migrate to data stream API>>.
During conversion, the alias’s indices become hidden backing indices for the
stream. The alias’s write index becomes the stream’s write index. The stream
still requires a matching index template with data stream enabled.

////
[source,console]
----
POST idx1/_doc/
{
    "message" : "testing",
    "@timestamp" : "2099-01-01"
}

POST idx2/_doc/
{
    "message" : "testing2",
    "@timestamp" : "2099-01-01"
}

POST _aliases
{
  "actions": [
    {
      "add": {
        "index": "idx1",
        "alias": "my-time-series-data",
        "is_write_index": true
      }
    },
    {
      "add": {
        "index": "idx2",
        "alias": "my-time-series-data"
      }
    }
  ]
}

PUT _index_template/template
{
  "index_patterns": ["my-time-series-data"],
  "data_stream": { }
}
----
// TEST[continued]
////

[source,console]
----
POST _data_stream/_migrate/my-time-series-data
----
// TEST[continued]

[discrete]
[[get-info-about-data-stream]]
=== Get information about a data stream

To get information about a data stream in {kib}, open the main menu and go to
*Stack Management > Index Management*. In the *Data Streams* view, click the
data stream's name.

You can also use the <<indices-get-data-stream,get data stream API>>.

////
[source,console]
----
POST my-data-stream/_rollover/
----
// TEST[continued]
////

[source,console]
----
GET _data_stream/my-data-stream
----
// TEST[continued]

[discrete]
[[delete-data-stream]]
=== Delete a data stream

To delete a data stream and its backing indices in {kib}, open the main menu and
go to *Stack Management > Index Management*. In the *Data Streams* view, click
the trash icon. The icon only displays if you have the `delete_index`
<<security-privileges, security privilege>> for the data stream.

You can also use the <<indices-delete-data-stream,delete data stream API>>.

[source,console]
----
DELETE _data_stream/my-data-stream
----
// TEST[continued]

////
[source,console]
----
DELETE _data_stream/*
DELETE _index_template/*
DELETE _component_template/my-*
DELETE _ilm/policy/my-lifecycle-policy
----
// TEST[continued]
////