How to do it…

To enable a rolling index, we need an index with an alias that points to it alone. For example, to set a log rolling index, we would follow these steps:

1. We need an index with a logs_write alias that points to it alone:

PUT /mylogs-000001
{
  "aliases": {
    "logs_write": {}
  }
}

The result will be an acknowledgement, as follows:

{
  "acknowledged" : true,
  "shards_acknowledged" : true,
  "index" : "mylogs-000001"
}

1. We can add the rolling to the logs_write alias in this way:

POST /logs_write/_rollover
{
  "conditions": {
    "max_age": "7d",
    "max_docs": 100000
  },
  "settings": {
    "index.number_of_shards": 3
  }
}

The result will be as follows:

{
  "acknowledged" : false,
  "shards_acknowledged" : false,
  "old_index" : "mylogs-000001",
  "new_index" : "mylogs-000002",
  "rolled_over" : false,
  "dry_run" : false,
  "conditions" : {
    "[max_docs: 100000]" : false,
    "[max_age: 7d]" : false
  }
}

1. In case your alias doesn't point to a single index, a similar error is returned:

{
"error" : {
"root_cause" : [
{
"type" : "illegal_argument_exception",
"reason" : "source alias maps to multiple indices
}
],
"type" : "illegal_argument_exception",
"reason" : "source alias maps to multiple indices"
},
"status" : 400
}