Etcd configuration for Vault backend storage

The Etcd storage backend is used to persist Vault's data in Etcd. It supports both the v2 and v3 Etcd APIs, and the version is automatically detected based on the version of the Etcd cluster.

• High Availability – the Etcd storage backend supports high availability. The v2 API has known issues with HA support and should not be used in HA scenarios.

• Community Supported – the Etcd storage backend is supported by CoreOS. 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 "etcd" {
  address  = "http://localhost:2379"
  etcd_api = "v3"
}

etcd parameters

• address (string: "http://localhost:2379") – Specifies the addresses of the Etcd instances as a comma-separated list. This can also be provided via the environment variable ETCD_ADDR.

• discovery_srv (string: "example.com") - Specifies the domain name to query for SRV records describing cluster endpoints. This can also be provided via the environment variable ETCD_DISCOVERY_SRV.

• discovery_srv_name (string: "vault") - Specifies the service name to use when querying for SRV records describing cluster endpoints. This can also be provided via the environment variable ETCD_DISCOVERY_SRV_NAME.

• etcd_api (string: "<varies>") – Specifies the version of the API to communicate with. By default, this is derived automatically. If the cluster version is 3.1+ and there has been no data written using the v2 API, the auto-detected default is v3.

• ha_enabled (string: "false") – Specifies if high availability should be enabled. This can also be provided via the environment variable ETCD_HA_ENABLED.

• path (string: "/vault/") – Specifies the path in Etcd where Vault data will be stored.

• sync (string: "true") – Specifies whether to sync the list of available Etcd services on startup. This is a string that is coerced into a boolean value. You may want to set this to false if your cluster is behind a proxy server and syncing causes Vault to fail.

• username (string: "") – Specifies the username to use when authenticating with the Etcd server. This can also be provided via the environment variable ETCD_USERNAME.

• password (string: "") – Specifies the password to use when authenticating with the Etcd server. This can also be provided via the environment variable ETCD_PASSWORD.

• tls_ca_file (string: "") – Specifies the path to the CA certificate used for Etcd communication. This defaults to system bundle if not specified.

• tls_cert_file (string: "") – Specifies the path to the certificate for Etcd communication.

• tls_key_file (string: "") – Specifies the path to the private key for Etcd communication.

• request_timeout (string: "5s") – Specifies timeout for requests to etcd. 5 seconds should be long enough for most cases, even with internal retry.

• lock_timeout (string: "15s") – Specifies lock timeout for master Vault instance. Set bigger value if you don't need faster recovery.

• max_receive_size (int) – Specifies the client-side response receive limit. Make sure that "max_receive_size" >= server-side default send/recv limit. ("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").

• max_send_size (int) – Specifies the client-side request send limit in bytes. Make sure that "max_send_size" < server-side default send/recv limit. ("--max-request-bytes" flag to etcd or "embed.Config.MaxRequestBytes").

etcd Examples

DNS discovery of cluster members

This example configures vault to discover the Etcd cluster members via SRV records as outlined in the DNS Discovery protocol documentation.

storage "etcd" {
  discovery_srv = "example.com"
}

Custom authentication

This example shows connecting to the Etcd cluster using a username and password.

storage "etcd" {
  username = "user1234"
  password = "pass5678"
}

Custom path

This example shows storing data in a custom path.

storage "etcd" {
  path = "my-vault-data/"
}

Enabling high availability

This example shows enabling high availability for the Etcd storage backend.

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

storage "etcd" {
  ha_enabled    = "true"
  ...
}