Failed to obtain shard lock – How to solve this Elasticsearch error

Opster Team

Aug-23, Version: 6.8-8.2

Briefly, this error occurs when Elasticsearch is unable to acquire a lock on a shard, usually due to concurrent operations on the same shard. This could be caused by a long-running operation, a node crash, or network issues. To resolve this, you can try to identify and stop the operation causing the lock, restart the node, or check for network connectivity issues. If the problem persists, you may need to consider reindexing the data.

This guide will help you check for common problems that cause the log ” {}: failed to obtain shard lock ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: index, shard.

Log Context

Log “{}: failed to obtain shard lock” classname is
We extracted the following from Elasticsearch source code for those seeking an in-depth context :

        } catch (IndexNotFoundException ex) {
            // that's fine - happens all the time no need to log
        } catch (FileNotFoundException | NoSuchFileException ex) {
  "Failed to open / find files while reading metadata snapshot"; ex);
        } catch (ShardLockObtainFailedException ex) {
   -> new ParameterizedMessage("{}: failed to obtain shard lock"; shardId); ex);
        return MetadataSnapshot.EMPTY;



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