Azure repositoryedit

You can use Azure Blob storage as a repository for Snapshot/Restore.


To enable Azure repositories, you have first to define your Azure storage settings as secure settings.

You can define these settings before the node is started, or call the Nodes reload secure settings API after the settings are defined to apply them to a running node.

bin/elasticsearch-keystore add azure.client.default.account
bin/elasticsearch-keystore add azure.client.default.key

Note that you can also define more than one account:

bin/elasticsearch-keystore add azure.client.default.account
bin/elasticsearch-keystore add azure.client.default.key
bin/elasticsearch-keystore add azure.client.secondary.account
bin/elasticsearch-keystore add azure.client.secondary.sas_token

For more information about these settings, see Client settings.

Supported Azure Storage Account types

The Azure repository type works with all Standard storage accounts

  • Standard Locally Redundant Storage - Standard_LRS
  • Standard Zone-Redundant Storage - Standard_ZRS
  • Standard Geo-Redundant Storage - Standard_GRS
  • Standard Read Access Geo-Redundant Storage - Standard_RAGRS

Premium Locally Redundant Storage (Premium_LRS) is not supported as it is only usable as VM disk storage, not as general storage.

Client settingsedit

The client that you use to connect to Azure has a number of settings available. The settings have the form azure.client.CLIENT_NAME.SETTING_NAME. By default, azure repositories use a client named default, but this can be modified using the repository setting client. For example:

PUT _snapshot/my_backup
  "type": "azure",
  "settings": {
    "client": "secondary"

Most client settings can be added to the elasticsearch.yml configuration file. For example:

azure.client.default.timeout: 10s
azure.client.default.max_retries: 7
azure.client.secondary.timeout: 30s

In this example, the client side timeout is 10s per try for the default account with 7 retries before failing. The endpoint suffix is and 30s per try for the secondary account with 3 retries.

The account, key, and sas_token storage settings are reloadable secure settings, which you add to the Elasticsearch keystore. For more information about creating and updating the Elasticsearch keystore, see Secure settings. After you reload the settings, the internal Azure clients, which are used to transfer the snapshot, utilize the latest settings from the keystore.

In progress snapshot or restore jobs will not be preempted by a reload of the storage secure settings. They will complete using the client as it was built when the operation started.

The following list contains the available client settings. Those that must be stored in the keystore are marked as "secure"; the other settings belong in the elasticsearch.yml file.

account (Secure, reloadable)
The Azure account name, which is used by the repository’s internal Azure client.
The Azure endpoint suffix to connect to. The default value is
key (Secure, reloadable)
The Azure secret key, which is used by the repository’s internal Azure client. Alternatively, use sas_token.
The number of retries to use when an Azure request fails. This setting helps control the exponential backoff policy. It specifies the number of retries that must occur before the snapshot fails. The default value is 3. The initial backoff period is defined by Azure SDK as 30s. Thus there is 30s of wait time before retrying after a first timeout or failure. The maximum backoff period is defined by Azure SDK as 90s.
The host name of a proxy to connect to Azure through. For example:
The port of a proxy to connect to Azure through. For example, azure.client.default.proxy.port: 8888.
Register a proxy type for the client. Supported values are direct, http, and socks. For example: azure.client.default.proxy.type: http. When proxy.type is set to http or socks, and proxy.port must also be provided. The default value is direct.
sas_token (Secure, reloadable)
A shared access signatures (SAS) token, which the repository’s internal Azure client uses for authentication. The SAS token must have read (r), write (w), list (l), and delete (d) permissions for the repository base path and all its contents. These permissions must be granted for the blob service (b) and apply to resource types service (s), container (c), and object (o). Alternatively, use key.
The client side timeout for any single request to Azure. The value should specify the time unit. For example, a value of 5s specifies a 5 second timeout. There is no default value, which means that Elasticsearch uses the default value set by the Azure client (known as 5 minutes). This setting can be defined globally, per account, or both.
The Azure endpoint to connect to. It must include the protocol used to connect to Azure.
The Azure secondary endpoint to connect to. It must include the protocol used to connect to Azure.

Repository settingsedit

The Azure repository supports following settings:

Azure named client to use. Defaults to default.
Container name. You must create the azure container before creating the repository. Defaults to elasticsearch-snapshots.

Specifies the path within container to repository data. Defaults to empty (root directory).

Don’t set base_path when configuring a snapshot repository for Elastic Cloud Enterprise. Elastic Cloud Enterprise automatically generates the base_path for each deployment so that multiple deployments may share the same bucket.

Big files can be broken down into multiple smaller blobs in the blob store during snapshotting. It is not recommended to change this value from its default unless there is an explicit reason for limiting the size of blobs in the repository. Setting a value lower than the default can result in an increased number of API calls to the Azure blob store during snapshot create as well as restore operations compared to using the default value and thus make both operations slower as well as more costly. Specify the chunk size as a value and unit, for example: 10MB, 5KB, 500B. Defaults to the maximum size of a blob in the Azure blob store which is 5TB.
When set to true metadata files are stored in compressed format. This setting doesn’t affect index files that are already compressed by default. Defaults to true.
(Optional, byte value) Maximum snapshot restore rate per node. Defaults to unlimited. Note that restores are also throttled through recovery settings.
(Optional, byte value) Maximum snapshot creation rate per node. Defaults to 40mb per second. Note that if the recovery settings for managed services are set, then it defaults to unlimited, and the rate is additionally throttled through recovery settings.

(Optional, Boolean) If true, the repository is read-only. The cluster can retrieve and restore snapshots from the repository but not write to the repository or create snapshots in it.

Only a cluster with write access can create snapshots in the repository. All other clusters connected to the repository should have the readonly parameter set to true.

If false, the cluster can write to the repository and create snapshots in it. Defaults to false.

If you register the same snapshot repository with multiple clusters, only one cluster should have write access to the repository. Having multiple clusters write to the repository at the same time risks corrupting the contents of the repository.

primary_only or secondary_only. Defaults to primary_only. Note that if you set it to secondary_only, it will force readonly to true.

Some examples, using scripts:

# The simplest one
PUT _snapshot/my_backup1
  "type": "azure"

# With some settings
PUT _snapshot/my_backup2
  "type": "azure",
  "settings": {
    "container": "backup-container",
    "base_path": "backups",
    "chunk_size": "32MB",
    "compress": true

# With two accounts defined in elasticsearch.yml (my_account1 and my_account2)
PUT _snapshot/my_backup3
  "type": "azure",
  "settings": {
    "client": "secondary"
PUT _snapshot/my_backup4
  "type": "azure",
  "settings": {
    "client": "secondary",
    "location_mode": "primary_only"

Example using Java:

        .put(Storage.CONTAINER, "backup-container")
        .put(Storage.CHUNK_SIZE, new ByteSizeValue(32, ByteSizeUnit.MB))

Repository validation rulesedit

According to the containers naming guide, a container name must be a valid DNS name, conforming to the following naming rules:

  • Container names must start with a letter or number, and can contain only letters, numbers, and the dash (-) character.
  • Every dash (-) character must be immediately preceded and followed by a letter or number; consecutive dashes are not permitted in container names.
  • All letters in a container name must be lowercase.
  • Container names must be from 3 through 63 characters long.

Linearizable register implementationedit

The linearizable register implementation for Azure repositories is based on Azure’s support for strongly consistent leases. Each lease may only be held by a single node at any time. The node presents its lease when performing a read or write operation on a protected blob. Lease-protected operations fail if the lease is invalid or expired. To perform a compare-and-exchange operation on a register, Elasticsearch first obtains a lease on the blob, then reads the blob contents under the lease, and finally uploads the updated blob under the same lease. This process ensures that the read and write operations happen atomically.