Briefly, this error occurs when Elasticsearch fails to restore the metadata state from a snapshot during a cluster recovery or migration process. This could be due to issues like corrupted snapshot files, insufficient permissions, or network connectivity problems. To resolve this, you can try the following: 1) Check and repair any corrupted snapshot files. 2) Ensure that Elasticsearch has the necessary permissions to access the snapshot files. 3) Verify your network connectivity. 4) If the issue persists, consider creating a new snapshot and restoring from that.
This guide will help you check for common problems that cause the log ” metadata state not restored; reason: {} ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: metadata.
Overview
Metadata in Elasticsearch refers to additional information stored for each document. This is achieved using the specific metadata fields available in Elasticsearch. The default behavior of some of these metadata fields can be customized during mapping creation.
Examples
Using _meta meta-field for storing application-specific information with the mapping:
PUT /my_index?pretty
{
"mappings": {
"_meta": {
"domain": "security",
"release_information": {
"date": "18-01-2020",
"version": "7.5"
}
}
}
}Notes
- In version 2.x, Elasticsearch had a total 13 meta fields available, which are: _index, _uid, _type, _id, _source, _size, _all, _field_names, _timestamp, _ttl, _parent, _routing, _meta
- In version 5.x, _timestamp and _ttl meta fields were removed.
- In version 6.x, the _parent meta field was removed.
- In version 7.x, _uid and _all meta fields were removed.
Log Context
Log “metadata state not restored; reason: {}” classname is GatewayService.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
@Override
public void onFailure(String message) {
recovered.set(false);
scheduledRecovery.set(false);
// don't remove the block here; we don't want to allow anything in such a case
logger.info("metadata state not restored; reason: {}"; message);
}
}
// used for testing
