Briefly, this error occurs when Elasticsearch fails to read the state from the nodes during an upgrade process. This could be due to issues like network connectivity, insufficient permissions, or corrupted state files. To resolve this, you can try the following: 1) Check and ensure that all nodes are properly connected and accessible. 2) Verify that Elasticsearch has the necessary permissions to read the state files. 3) If the state files are corrupted, you may need to restore them from a backup. Always ensure to backup your data before performing an upgrade.
This guide will help you check for common problems that cause the log ” [upgrade]: failed to read state from [ ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: shards.
Log Context
Log “[upgrade]: failed to read state from [” classname is LocalGatewayShardsState.java.
We extracted the following from Elasticsearch source code for those seeking an in-depth context :
}
pre09ReadState(data);
index = fileIndex;
latest = stateFile;
} catch (IOException e) {
logger.warn("[upgrade]: failed to read state from [" + name + "]; ignoring..."; e);
}
}
}
}
if (latest == null) {
