Azure repository
editAzure repository
editYou can use Azure Blob storage as a repository for Snapshot/Restore.
Setup
editTo 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 settings
editThe 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:
resp = client.snapshot.create_repository( name="my_backup", repository={ "type": "azure", "settings": { "client": "secondary" } }, ) print(resp)
const response = await client.snapshot.createRepository({ name: "my_backup", repository: { type: "azure", settings: { client: "secondary", }, }, }); console.log(response);
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.default.endpoint_suffix: core.chinacloudapi.cn 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
core.chinacloudapi.cn
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.
-
endpoint_suffix
-
The Azure endpoint suffix to connect to. The default value is
core.windows.net
. -
key
(Secure, reloadable) -
The Azure secret key, which is used by the repository’s internal Azure client. Alternatively, use
sas_token
. -
max_retries
-
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 as30s
. Thus there is30s
of wait time before retrying after a first timeout or failure. The maximum backoff period is defined by Azure SDK as90s
. -
proxy.host
-
The host name of a proxy to connect to Azure through. For example:
azure.client.default.proxy.host: proxy.host
. -
proxy.port
-
The port of a proxy to connect to Azure through. For example,
azure.client.default.proxy.port: 8888
. -
proxy.type
-
Register a proxy type for the client. Supported values are
direct
,http
, andsocks
. For example:azure.client.default.proxy.type: http
. Whenproxy.type
is set tohttp
orsocks
,proxy.host
andproxy.port
must also be provided. The default value isdirect
. -
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
. -
timeout
-
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. -
endpoint
- The Azure endpoint to connect to. It must include the protocol used to connect to Azure.
-
secondary_endpoint
- The Azure secondary endpoint to connect to. It must include the protocol used to connect to Azure.
Repository settings
editThe Azure repository supports following settings:
-
client
-
Azure named client to use. Defaults to
default
. -
container
-
Container name. You must create the azure container before creating the repository.
Defaults to
elasticsearch-snapshots
. -
base_path
-
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 thebase_path
for each deployment so that multiple deployments may share the same bucket. -
chunk_size
-
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 is5TB
. -
compress
-
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 totrue
. -
max_restore_bytes_per_sec
- (Optional, byte value) Maximum snapshot restore rate per node. Defaults to unlimited. Note that restores are also throttled through recovery settings.
-
max_snapshot_bytes_per_sec
-
(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.
-
readonly
-
(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 totrue
.If
false
, the cluster can write to the repository and create snapshots in it. Defaults tofalse
.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.
-
location_mode
-
primary_only
orsecondary_only
. Defaults toprimary_only
. Note that if you set it tosecondary_only
, it will forcereadonly
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:
client.admin().cluster().preparePutRepository("my_backup_java1") .setType("azure").setSettings(Settings.builder() .put(Storage.CONTAINER, "backup-container") .put(Storage.CHUNK_SIZE, new ByteSizeValue(32, ByteSizeUnit.MB)) ).get();
Repository validation rules
editAccording 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 implementation
editThe 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.