Briefly, this error occurs when there is a mismatch in the Elasticsearch versions across different nodes in a cluster. This can happen if you are trying to connect nodes with different versions or if a node has been upgraded incorrectly. To resolve this issue, ensure all nodes in the cluster are running the same version of Elasticsearch. If a node has been upgraded, make sure it was done correctly and that the node was restarted after the upgrade. Also, check the network connectivity between the nodes to ensure they can communicate properly.
This guide will help you check for common problems that cause the log ” error processing handshake version [” + version + “] received on [” + channel + “]; closing channel ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: version.
Overview
A version corresponds to the Elasticsearch built-in tracking system that tracks the changes in each document’s update. When a document is indexed for the first time, it is assigned a version 1 using _version key. When the same document gets a subsequent update, the _version is incremented by 1 with every index, update or delete API call.
What it is used for
A version is used to handle the concurrency issues in Elasticsearch which come into play during simultaneous accessing of an index by multiple users. Elasticsearch handles this issue with an optimistic locking concept using the _version parameter to avoid letting multiple users edit the same document at the same time and protects users from generating incorrect data.
Notes
You cannot see the history of the document using _version. That means Elasticsearch does not use _version to keep a track of original changes that had been performed on the document. For example, if a document has been updated 10 times, it’s _version would be marked by Elasticsearch as 11, but you cannot go back and see what version 5 of the document looked like. This has to be implemented independently.
Common problems
If optimistic locking is not implemented while making updates to a document, Elasticsearch may return a conflict error with the 409 status code, which means that multiple users are trying to update the same version of the document at the same time.
POST /ratings/123?version=50
{
"name": "Joker",
"rating": 50
}Log Context
Log “error processing handshake version [” + version + “] received on [” + channel + “]; closing channel” classname is InboundHandler.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
message.takeBreakerReleaseControl()
);
try {
handshaker.handleHandshake(transportChannel; requestId; stream);
} catch (Exception e) {
logger.warn(() -> "error processing handshake version [" + version + "] received on [" + channel + "]; closing channel"; e);
channel.close();
}
} else {
final TransportChannel transportChannel;
final RequestHandlerRegistry reg;
