[[repository-gcs]]
=== Google Cloud Storage Repository Plugin

The GCS repository plugin adds support for using the https://cloud.google.com/storage/[Google Cloud Storage]
service as a repository for {ref}/modules-snapshots.html[Snapshot/Restore].

[[repository-gcs-install]]
[float]
==== Installation

This plugin can be installed using the plugin manager:

[source,sh]
----------------------------------------------------------------
sudo bin/elasticsearch-plugin install repository-gcs
----------------------------------------------------------------

NOTE: The plugin requires new permission to be installed in order to work

The plugin must be installed on every node in the cluster, and each node must
be restarted after installation.

[[repository-gcs-remove]]
[float]
==== Removal

The plugin can be removed with the following command:

[source,sh]
----------------------------------------------------------------
sudo bin/elasticsearch-plugin remove repository-gcs
----------------------------------------------------------------

The node must be stopped before removing the plugin.

[[repository-gcs-usage]]
==== Getting started

The plugin uses the https://cloud.google.com/storage/docs/json_api/[Google Cloud Storage JSON API] (v1)
to connect to the Storage service. If this is the first time you use Google Cloud Storage, you first
need to connect to the https://console.cloud.google.com/[Google Cloud Platform Console] and create a new
project. Once your project is created, you must enable the Cloud Storage Service for your project.

[[repository-gcs-creating-bucket]]
===== Creating a Bucket

Google Cloud Storage service uses the concept of https://cloud.google.com/storage/docs/key-terms[Bucket]
as a container for all the data. Buckets are usually created using the
https://console.cloud.google.com/[Google Cloud Platform Console]. The plugin will not automatically
create buckets.

To create a new bucket:

1. Connect to the https://console.cloud.google.com/[Google Cloud Platform Console]
2. Select your project
3. Got to the https://console.cloud.google.com/storage/browser[Storage Browser]
4. Click the "Create Bucket" button
5. Enter a the name of the new bucket
6. Select a storage class
7. Select a location
8. Click the "Create" button

The bucket should now be created.

[[repository-gcs-service-authentication]]
===== Service Authentication

The plugin supports two authentication modes:

* the built-in <<repository-gcs-using-compute-engine, Compute Engine authentication>>. This mode is
recommended if your elasticsearch node is running on a Compute Engine virtual machine.

* the <<repository-gcs-using-service-account, Service Account>> authentication mode.

[[repository-gcs-using-compute-engine]]
===== Using Compute Engine
When running on Compute Engine, the plugin use the Google's built-in authentication mechanism to
authenticate on the Storage service. Compute Engine virtual machines are usually associated to a
default service account. This service account can be found in the VM instance details in the
https://console.cloud.google.com/compute/[Compute Engine console].

To indicate that a repository should use the built-in authentication,
the repository `service_account` setting must be set to `_default_`:

[source,json]
----
PUT _snapshot/my_gcs_repository_on_compute_engine
{
  "type": "gcs",
  "settings": {
    "bucket": "my_bucket",
    "service_account": "_default_"
  }
}
----
// CONSOLE

NOTE: The Compute Engine VM must be allowed to use the Storage service. This can be done only at VM
creation time, when "Storage" access can be configured to "Read/Write" permission. Check your
instance details at the section "Cloud API access scopes".

[[repository-gcs-using-service-account]]
===== Using a Service Account
If your elasticsearch node is not running on Compute Engine, or if you don't want to use Google
built-in authentication mechanism, you can authenticate on the Storage service using a
https://cloud.google.com/iam/docs/overview#service_account[Service Account] file.

To create a service account file:
1. Connect to the https://console.cloud.google.com/[Google Cloud Platform Console]
2. Select your project
3. Got to the https://console.cloud.google.com/permissions[Permission] tab
4. Select the https://console.cloud.google.com/permissions/serviceaccounts[Service Accounts] tab
5. Click on "Create service account"
6. Once created, select the new service account and download a JSON key file

A service account file looks like this:

[source,json]
----
{
  "type": "service_account",
  "project_id": "your-project-id",
  "private_key_id": "...",
  "private_key": "-----BEGIN PRIVATE KEY-----\n...\n-----END PRIVATE KEY-----\n",
  "client_email": "service-account-for-your-repository@your-project-id.iam.gserviceaccount.com",
  "client_id": "...",
  "auth_uri": "https://accounts.google.com/o/oauth2/auth",
  "token_uri": "https://accounts.google.com/o/oauth2/token",
  "auth_provider_x509_cert_url": "https://www.googleapis.com/oauth2/v1/certs",
  "client_x509_cert_url": "..."
}
----

This file must be copied in the `config` directory of the elasticsearch installation and on
every node of the cluster.

To indicate that a repository should use a service account file:

[source,json]
----
PUT _snapshot/my_gcs_repository
{
  "type": "gcs",
  "settings": {
    "bucket": "my_bucket",
    "service_account": "service_account.json"
  }
}
----
// CONSOLE


[[repository-gcs-bucket-permission]]
===== Set Bucket Permission

The service account used to access the bucket must have the "Writer" access to the bucket:

1. Connect to the https://console.cloud.google.com/[Google Cloud Platform Console]
2. Select your project
3. Got to the [https://console.cloud.google.com/storage/browser]Storage Browser
4. Select the bucket and "Edit bucket permission"
5. The service account must be configured as a "User" with "Writer" access


[[repository-gcs-repository]]
==== Create a Repository

Once everything is installed and every node is started, you can create a new repository that
uses Google Cloud Storage to store snapshots:

[source,json]
----
PUT _snapshot/my_gcs_repository
{
  "type": "gcs",
  "settings": {
    "bucket": "my_bucket",
    "service_account": "service_account.json"
  }
}
----
// CONSOLE

The following settings are supported:

`bucket`::

    The name of the bucket to be used for snapshots. (Mandatory)

`service_account`::

    The service account to use. It can be a relative path to a service account JSON file
    or the value `_default_` that indicate to use built-in Compute Engine service account.

`base_path`::

    Specifies the path within bucket to repository data. Defaults to
    the root of the bucket.

`chunk_size`::

    Big files can be broken down into chunks during snapshotting if needed.
    The chunk size can be specified in bytes or by using size value notation,
    i.e. `1g`, `10m`, `5k`. Defaults to `100m`.

`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 to `false`.

`application_name`::

    Name used by the plugin when it uses the Google Cloud JSON API. Setting
    a custom name can be useful to authenticate your cluster when requests
    statistics are logged in the Google Cloud Platform. Default to `repository-gcs`
