Add a rollover policy to the setup plugin

[f-galland]

Description

This PR is meant as a proof of concept that a rollover policy can be set up from a plugin, outside the Index Management plugin itself.
It does so by writing a policy json to the .opendistro-ism-config much like the Index Management plugin itself would do.

Issues Resolved

wazuh/wazuh-indexer#591

[f-galland]

Policy Document

The setup plugin has been modified to index a document to the .opendistro-ism-config index which look as follows:

{
  "policy": {
    "policy_id": "wazuh_rollover_policy",
    "description": "Example rollover policy.",
    "last_updated_time": 1738947466825,
    "schema_version": 21,
    "error_notification": null,
    "default_state": "rollover",
    "states": [
      {
        "name": "rollover",
        "actions": [
          {
            "retry": {
              "count": 3,
              "backoff": "exponential",
              "delay": "1m"
            },
            "rollover": {
              "min_doc_count": 1,
              "copy_alias": false
            }
          }
        ],
        "transitions": []
      }
    ],
    "ism_template": [
      {
        "index_patterns": [
          "test-index-*"
        ],
        "priority": 100,
        "last_updated_time": 1738947466825
      }
    ],
    "user": {
      "name": "admin",
      "backend_roles": [
        "admin"
      ],
      "roles": [
        "own_index",
        "all_access"
      ],
      "custom_attribute_names": [],
      "user_requested_tenant": null
    }
  }
}

[f-galland]

Index Management index template

During testing we found out that our plugin was quicker to load than the Index Management one, so a template must be set up for the .opendistro-ism-config index before creation.

We took the mappings from it from here:

• https://github.com/opensearch-project/index-management/blob/2.18.0.0/src/main/resources/mappings/opendistro-ism-config.json

[f-galland]

Trigger the job

An index needs to be written, which matches the index pattern the policy expects, while also being set up as the write index for the rollover alias:

curl -XPUT http://localhost:9200/test-index-0000 -H 'Content-Type: application/json' -d '{"aliases":{"test-alias":{"is_write_index":true}}}'

[f-galland]

Check that indices are being rotated

In order to speed up execution of the rollover policy, the following command can be issued:

curl -XPUT http://localhost:9200/_cluster/settings?pretty=true -H'Content-Type: application/json' -d '{"persistent": {"plugins.index_state_management.job_interval":1}}'

Now we can index new commands pointing towards our index alias:

curl -XPOST http://localhost:9200/test-alias/_doc -H 'Content-Type: application/json' -d '{"field":"value"}'

[f-galland]

Check the policy is reckoned

We can now check whether the ISM plugin is recognizing our policy and will apply it to the right index

$ curl 'http://localhost:9200/_plugins/_ism/explain?pretty'
{
  "test-index-0000" : {
    "index.plugins.index_state_management.policy_id" : "wazuh_rollover_policy",
    "index.opendistro.index_state_management.policy_id" : "wazuh_rollover_policy",
    "index" : "test-index-0000",
    "index_uuid" : "v6dYvuxlS9mJ3DE_78-IyA",
    "policy_id" : "wazuh_rollover_policy",
    "enabled" : true
  },
  "total_managed_indices" : 1
}