ILM policy not triggering a new index

Elastic Stack Elasticsearch
1

I have index created on a weekly basis via a pipeline which creates a index ending with _yyyymmddw, but was relying on ILM policy sharding based on if it reaches the 50gb limit. Even though the index action shows as rollover nothing is happening and it has reached almost 600gb.

I see the error of index rollover alias. is there anyway it can pick up the first index name it creates for the rollover?

ILM policy on the index

{
  "policy": "1-week-retention",
  "phase_definition": {
    "min_age": "0ms",
    "actions": {
      "rollover": {
        "max_age": "30d",
        "max_primary_shard_size": "50gb"
      },
      "set_priority": {
        "priority": 100
      }
    }
  },
  "version": 3,
  "modified_date_in_millis": 1742225274621
}

ILM explain

{
  "indices": {
    "nifiaudit_60187_review_20250312": {
      "index": "nifiaudit_60187_review_20250312",
      "managed": true,
      "policy": "1-week-retention",
      "index_creation_date_millis": 1742225294227,
      "time_since_index_creation": "20.12h",
      "lifecycle_date_millis": 1742225294227,
      "age": "20.12h",
      "phase": "hot",
      "phase_time_millis": 1742296780127,
      "action": "rollover",
      "action_time_millis": 1742288451847,
      "step": "ERROR",
      "step_time_millis": 1742297380160,
      "failed_step": "check-rollover-ready",
      "is_auto_retryable_error": true,
      "failed_step_retry_count": 7,
      "step_info": {
        "type": "illegal_argument_exception",
        "reason": "setting [index.lifecycle.rollover_alias] for index [nifiaudit_60187_review_20250312] is empty or not defined"
      },
      "phase_execution": {
        "policy": "1-week-retention",
        "phase_definition": {
          "min_age": "0ms",
          "actions": {
            "rollover": {
              "max_primary_shard_size": "50gb"
            },
            "set_priority": {
              "priority": 100
            }
          }
        },
        "version": 4,
        "modified_date_in_millis": 1742288359047
      }
    }
  }
}
2

Hi,
ILM (Index Lifecycle Management) works with aliases, and according to your error, you don't have one.
The documentation for Rollover and how it works with Aliases : Rollover | Elasticsearch Guide [8.17] | Elastic

Do you know about data streams? In your case, it might be interesting, it simplifies the system I find. Are your data timestamped? Do you need to modify them, or just index them?