postgres

У меня тоже не работало с действием open, сделай просто пустую проверку, без действия, только с условием на проверку min_index_age, пример:

{
    "policy": {
        "policy_id": "Delete_logstash_logs_45d",
        "description": "Delete logstash indices after 45 days",
        "default_state": "check_age",
        "states": [
            {
                "name": "check_age",
                "actions": [],
                "transitions": [
                    {
                        "state_name": "Delete",
                        "conditions": {
                            "min_index_age": "45d"
                        }
                    }
                ]
            },
            {
                "name": "Delete",
                "actions": [
                    {
                        "delete": {}
                    }
                ],
                "transitions": []
            }
        ],
        "ism_template": [
            {
                "index_patterns": [
                    "logstash-*"
                ],
                "priority": 100
            }
        ]
    }
}