Attempted to send a bulk

我现在集群每天的日志量大概3T，59个节点，60个data node，3个client节点，4个master节点，用kafka做了缓冲，但是logstash从kafka取数写入到es的时候，总是有报错："Attempted to send a bulk request to Elasticsearch configured at 、but an error occurred and it failed! Are you sure you can reach elasticsearch from this machine using the configuration provided?",、error_message=>"[503] {"error":{"root_cause":[{"type":"cluster_block_exception","reason":"blocked by: [SERVICE_UNAVAILABLE/2/no master];"}],"type":"cluster_block_exception","reason":"blocked by: [SERVICE_UNAVAILABLE/2/no master];"},"status":503}" 不知道什么原因