Briefly, this error occurs when Elasticsearch fails to create a blob container, which is typically used for storing snapshots. This could be due to insufficient permissions, incorrect configuration, or connectivity issues with the storage backend. To resolve this, ensure that Elasticsearch has the necessary permissions to create and access the blob container. Check your configuration settings for any errors and verify that the storage backend (like AWS S3, Azure Storage, etc.) is accessible and functioning properly.
This guide will help you check for common problems that cause the log ” failed to create blob container ” to appear. To understand the issues related to this log, read the explanation below about the following Elasticsearch concepts: repositories, plugins, container.
Overview
An Elasticsearch snapshot provides a backup mechanism that takes the current state and data in the cluster and saves it to a repository (read snapshot for more information). The backup process requires a repository to be created first. The repository needs to be registered using the _snapshot endpoint, and multiple repositories can be created per cluster. The following repository types are supported:
Repository types
| Repository type | Configuration type |
|---|---|
| Shared file system | Type: “fs” |
| S3 | Type : “s3” |
| HDFS | Type :“hdfs” |
| Azure | Type: “azure” |
| Google Cloud Storage | Type : “gcs” |
Examples
To register an “fs” repository:
PUT _snapshot/my_repo_01
{
"type": "fs",
"settings": {
"location": "/mnt/my_repo_dir"
}
}Notes and good things to know
- S3, HDFS, Azure and Google Cloud require a relevant plugin to be installed before it can be used for a snapshot.
- The setting, path.repo: /mnt/my_repo_dir needs to be added to elasticsearch.yml on all the nodes if you are planning to use the repo type of file system. Otherwise, it will fail.
- When using remote repositories, the network bandwidth and repository storage throughput should be high enough to complete the snapshot operations normally, otherwise you will end up with partial snapshots.
Log Context
Log “failed to create blob container” class name is HdfsBlobStore.java. We extracted the following from Elasticsearch source code for those seeking an in-depth context :
try {
mkdirs(path);
} catch (FileAlreadyExistsException ok) {
// behaves like Files.createDirectories
} catch (IOException ex) {
throw new ElasticsearchException("failed to create blob container"; ex);
}
}
return path;
}
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