Magento 2 Solved: cluster_block_exception

error: cluster_block_exception [TOO_MANY_REQUESTS/12/disk usage exceeded flood-stage watermark, index has read-only-allow-delete block] .

This error means you do not have enough disk space to store or update data. The flood storage watermark is 95% default, so when it exceeds, the above error is shown and it puts the Elasticsearch into read-only mode. So you need to free up disk space or enlarge it.

Steps to Solve Reindex issue with Elasticsearch: run below cmd

curl -XPUT -H "Content-Type: application/json" http://localhost:9200/_cluster/settings -d '{ "transient": { "cluster.routing.allocation.disk.threshold_enabled": false } }'

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

php bin/magento indexer:reindex