---
layout: docs
page_title: Google Cloud Storage - Storage Backends - Configuration
description: |-
  The Google Cloud Storage storage backend is used to persist Vault's data in
  Google Cloud Storage.
---

# Google Cloud Storage Storage Backend

The Google Cloud Storage storage backend is used to persist Vault's data in
[Google Cloud Storage][gcs-docs].

- **High Availability** – the Google Cloud Storage storage backend supports high
  availability. Because the Google Cloud Storage storage backend uses the system
  time on the Vault node to acquire sessions, clock skew across Vault servers
  can cause lock contention.

- **Community Supported** – the Google Cloud Storage storage backend is
  supported by the community. While it has undergone review by HashiCorp
  employees, they may not be as knowledgeable about the technology. If you
  encounter problems with them, you may be referred to the original author.

```hcl
storage "gcs" {
  bucket = "my-storage-bucket"
}
```

For more information on schemas or Google Cloud Storage, please see the [Google
Cloud Storage documentation][gcs-docs].

## `gcs` Setup

To use the Google Cloud Storage Vault storage backend, you must have a Google
Cloud Platform account with permissions to create Google Cloud Storage buckets.

To use the Google Cloud Storage Vault storage backend, you must have a Google
Cloud Platform account. Either using the API or web interface, create a bucket
using the [`gsutil`][cloud-sdk] command. Bucket names must be globally unique
across all of Google Cloud, so choose a unique name:

```shell-session
$ gsutil mb gs://mycompany-vault-data
```

Even though the data is encrypted in transit and at rest, be sure to set the
appropriate permissions on the bucket to limit exposure. You may want to create
a service account that limits Vault's interactions with Google Cloud to objects
in the storage bucket using IAM permissions.

Here is a sample [Google Cloud IAM][iam] policy that grants the proper
permissions to a [service account][service-accounts]. Be sure to replace the
value with the value for your service account.

```json
{
  "bindings": [
    {
      "role": "roles/storage.objectAdmin",
      "members": ["serviceAccount:my-vault@gserviceaccount.com"]
    }
  ]
}
```

Then give Vault the service account's credential file as a configuration option.

For more information on schemas or Google Cloud Storage, please see the [Google
Cloud Storage documentation][gcs-docs].

## `gcs` Authentication

The Google Cloud Storage Vault storage backend uses the official Google Cloud
Golang SDK. This means it supports the common ways of [providing credentials to
Google Cloud][cloud-creds].

1. The environment variable `GOOGLE_APPLICATION_CREDENTIALS`. This is specified
   as the **path** to a Google Cloud credentials file, typically for a service
   account. If this environment variable is present, the resulting credentials are
   used. If the credentials are invalid, an error is returned.

1. Default instance credentials. When no environment variable is present, the
   default service account credentials are used.

For more information on service accounts, please see the [Google Cloud Service
Accounts documentation][service-accounts].

To use this storage backend, the service account must have the following
minimum scope(s):

```text
https://www.googleapis.com/auth/devstorage.read_write
```

## `gcs` Parameters

- `bucket` `(string: <required>)` – Specifies the name of the bucket to use for
  storage. Alternatively, this parameter can be omitted and the `GOOGLE_STORAGE_BUCKET` 
  environment variable can be used to set the name of the bucket. If both the environment
  variable and the parameter in the stanza are set, the value of the environment variable
  will take precedence.

- `chunk_size` `(string: "8192")` – Specifies the maximum size (in kilobytes) to
  send in a single request. If set to 0, it will attempt to send the whole
  object at once, but will not retry any failures. If you are not storing large
  objects in Vault, it is recommended to set this to a low value (minimum is
  256), since it will reduce the amount of memory Vault uses. Alternatively, this parameter
  can be omitted and the `GOOGLE_STORAGE_CHUNK_SIZE` environment variable can be used to set 
  the chunk size. If both the environment variable and the parameter in the stanza are set, 
  the value of the environment variable will take precedence.

- `max_parallel` `(int: 128)` - Specifies the maximum number of parallel
  operations to take place.

### High Availability Parameters

- `ha_enabled` `(string: "false")` - Specifies if high availability mode is
  enabled. This is a boolean value, but it is specified as a string like "true"
  or "false". Alternatively, this parameter can be omitted and the 
  `GOOGLE_STORAGE_HA_ENABLED` environment variable can be used to 
  enable or disable high availability. If both the environment variable and 
  the parameter in the stanza are set, the value of the environment variable will 
  take precedence.
  
## `gcs` Examples

### High Availability

This example shows configuring Google Cloud Storage with high availability
enabled.

```hcl
api_addr = "https://vault-leader.my-company.internal"

storage "gcs" {
  bucket        = "mycompany-vault-data"
  ha_enabled    = "true"
}
```

### Custom Chunk Size

This example shows setting a custom chunk size for uploads. When uploading large
data to Vault, setting a lower number can reduce Vault's memory consumption, but
will increase the number of outbound requests.

```hcl
storage "gcs" {
  bucket     = "mycompany-vault-data"
  chunk_size = "512"
}
```

[cloud-creds]: https://cloud.google.com/docs/authentication/production#providing_credentials_to_your_application
[cloud-sdk]: https://cloud.google.com/sdk/downloads
[gcs-docs]: https://cloud.google.com/storage/docs/
[iam]: https://cloud.google.com/iam/docs/
[service-accounts]: https://cloud.google.com/compute/docs/access/service-accounts
