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

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[[indices-rollover-index]]
== Rollover Index
The rollover index API rolls an alias over to a new index when the existing
index is considered to be too large or too old.
The API accepts a single alias name and a list of `conditions`. The alias
must point to a single index only. If the index satisfies the specified
conditions then a new index is created and the alias is switched to point to
the new alias.
[source,js]
--------------------------------------------------
PUT /logs-0001 <1>
{
"aliases": {
"logs_write": {}
}
}
POST logs_write/_rollover <2>
{
"conditions": {
"max_age": "7d",
"max_docs": 1000
}
}
--------------------------------------------------
// CONSOLE
<1> Creates an index called `logs-0001` with the alias `logs_write`.
<2> If the index pointed to by `logs_write` was created 7 or more days ago, or
contains 1,000 or more documents, then the `logs-0002` index is created
and the `logs_write` alias is updated to point to `logs-0002`.
The above request might return the following response:
[source,js]
--------------------------------------------------
{
"old_index": "logs-0001",
"new_index": "logs-0002",
"rolled_over": true, <1>
"dry_run": false, <2>
"conditions": { <3>
"[max_age: 7d]": false,
"[max_docs: 1000]": true
}
}
--------------------------------------------------
<1> Whether the index was rolled over.
<2> Whether the rollover was dry run.
<3> The result of each condition.
[float]
=== Naming the new index
If the name of the existing index ends with `-` and a number -- e.g.
`logs-0001` -- then the name of the new index will follow the same pattern,
just incrementing the number (`logs-0002`).
If the old name doesn't match this pattern then you must specify the name for
the new index as follows:
[source,js]
--------------------------------------------------
POST my_alias/_rollover/my_new_index_name
{...}
--------------------------------------------------
[float]
=== Defining the new index
The settings, mappings, and aliases for the new index are taken from any
matching <<indices-templates,index templates>>. Additionally, you can specify
`settings`, `mappings`, and `aliases` in the body of the request, just like the
<<indices-create-index,create index>> API. Values specified in the request
override any values set in matching index templates. For example, the following
`rollover` request overrides the `index.number_of_shards` setting:
[source,js]
--------------------------------------------------
PUT /logs-0001
{
"aliases": {
"logs_write": {}
}
}
POST logs_write/_rollover
{
"conditions" : {
"max_age": "7d",
"max_docs": 1000
},
"settings": {
"index.number_of_shards": 2
}
}
--------------------------------------------------
// CONSOLE
[float]
=== Dry run
The rollover API supports `dry_run` mode, where request conditions can be
checked without performing the actual rollover:
[source,js]
--------------------------------------------------
PUT /logs-0001
{
"aliases": {
"logs_write": {}
}
}
POST logs_write/_rollover?dry_run
{
"conditions" : {
"max_age": "7d",
"max_docs": 1000
}
}
--------------------------------------------------
// CONSOLE