Google Cloud Storage configuration for Vault backend storage

The Google Cloud Storage storage backend is used to persist Vault's data in Google Cloud Storage.

• 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.

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

For more information on schemas or Google Cloud Storage, please see the Google Cloud Storage documentation.

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 command. Bucket names must be globally unique across all of Google Cloud, so choose a unique name:

$ 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 policy that grants the proper permissions to a service account. Be sure to replace the value with the value for your service account.

{
  "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 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.

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.

2. 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.

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

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.

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.

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