Fix for Magento ElasticSearch/OpenSearch Catalog index set to read-only

If you encounter the following error during Magento's indexing process:

Catalog Search index process error during indexation:

{
  "error": {
    "root_cause": [
      {
        "type": "cluster_block_exception",
        "reason": "index [update_new_product_1_v261] blocked by: [TOO_MANY_REQUESTS/12/disk usage exceeded flood-stage watermark, index has read-only-allow-delete block];"
      }
    ]
  }
}

This indicates that Elasticsearch has set the index to read-only due to disk space constraints. To resolve this issue:

1. Free up disk space to ensure sufficient storage for indexing.

2. Remove the read-only restriction by executing the following command in the CLI:

   curl -X PUT "localhost:9200/_all/_settings" -H "Content-Type: application/json" -d '{
     "index.blocks.read_only_allow_delete": null
   }'
   

This will restore write access to the indices, allowing the indexing process to proceed normally.