Briefly, this error occurs when Elasticsearch encounters an unexpected issue during its operations. This could be due to a variety of reasons such as insufficient memory, incorrect configurations, or network connectivity issues. To resolve this, you can check the Elasticsearch logs for more detailed error messages. Ensure that the Elasticsearch cluster has enough memory and the configurations are correct. Also, verify that all nodes in the cluster are reachable and there are no network issues.
This guide will help you check for common problems that cause the log ” failure caught ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: bulk.
Overview
In Elasticsearch, when using the Bulk API it is possible to perform many write operations in a single API call, which increases the indexing speed. Using the Bulk API is more efficient than sending multiple separate requests. This can be done for the following four actions:
- Index
- Update
- Create
- Delete
Examples
The bulk request below will index a document, delete another document, and update an existing document.
POST _bulk
{ "index" : { "_index" : "myindex", "_id" : "1" } }
{ "field1" : "value" }
{ "delete" : { "_index" : "myindex", "_id" : "2" } }
{ "update" : {"_id" : "1", "_index" : "myindex"} }
{ "doc" : {"field2" : "value5"} }Notes
- Bulk API is useful when you need to index data streams that can be queued up and indexed in batches of hundreds or thousands, such as logs.
- There is no correct number of actions or limits to perform on a single bulk call, but you will need to figure out the optimum number by experimentation, given the cluster size, number of nodes, hardware specs etc.
Log Context
Log “failure caught” classname is BulkUdpService.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
public void exceptionCaught(ChannelHandlerContext ctx; ExceptionEvent e) throws Exception {
if (e.getCause() instanceof BindException) {
// ignore; this happens when we retry binding to several ports; its fine if we fail...
return;
}
logger.warn("failure caught"; e.getCause());
}
}
class BulkListener implements BulkProcessor.Listener {
