Zookeeper configuration for Vault backend storage

The Zookeeper storage backend is used to persist Vault's data in Zookeeper.

• High Availability – the Zookeeper storage backend supports high availability.

• Community Supported – the Zookeeper 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 "zookeeper" {
  address = "localhost:2181"
  path    = "vault/"
}

zookeeper parameters

• address (string: "localhost:2181") – Specifies the addresses of the Zookeeper instances as a comma-separated list.

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

The following optional settings can be used to configure zNode ACLs:

• auth_info (string: "") – Specifies an authentication string in Zookeeper AddAuth format. For example, digest:UserName:Password could be used to authenticate as user UserName using password Password with the digest mechanism.

• znode_owner (string: "") – If specified, Vault will always set all permissions (CRWDA) to the ACL identified here via the Schema and User parts of the Zookeeper ACL format. The expected format is schema:user-ACL-match, for example:

  # Access for user "UserName" with corresponding digest "HIDfRvTv623G=="
  digest:UserName:HIDfRvTv623G==
  
  # Access from localhost only
  ip:127.0.0.1
  
  # Access from any host on the 70.95.0.0 network (Zookeeper 3.5+)
  ip:70.95.0.0/16
  

• tls_enabled (bool: false) – Specifies if TLS communication with the Zookeeper backend has to be enabled.

• tls_ca_file (string: "") – Specifies the path to the CA certificate file used for Zookeeper communication. Multiple CA certificates can be provided in the same file.

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

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

• tls_min_version (string: "tls12") – Specifies the minimum TLS version to use. Accepted values are "tls10", "tls11", "tls12" or "tls13".

• tls_skip_verify (bool: false) – Disable verification of TLS certificates. Using this option is highly discouraged.

• tls_verify_ip (bool: false) - This property comes into play only when 'tls_skip_verify' is set to false. When 'tls_verify_ip' is set to 'true', the zookeeper server's IP is verified in the presented certificates CN/SAN entry. When set to 'false' the server's DNS name is verified in the certificates CN/SAN entry.

zookeeper examples

Custom address and path

This example shows configuring Vault to communicate with a Zookeeper installation running on a custom port and to store data at a custom path.

storage "zookeeper" {
  address = "localhost:3253"
  path    = "my-vault-data/"
}

zNode Vault user only

This example instructs Vault to set an ACL on all of its zNodes which permit access only to the user "vaultUser". As per Zookeeper's ACL model, the digest value in znode_owner must match the user in znode_owner.

storage "zookeeper" {
  znode_owner = "digest:vaultUser:raxgVAfnDRljZDAcJFxznkZsExs="
  auth_info   = "digest:vaultUser:abc"
}

zNode localhost only

This example instructs Vault to only allow access from localhost. As this is the ip no auth_info is required since Zookeeper uses the address of the client for the ACL check.

storage "zookeeper" {
  znode_owner = "ip:127.0.0.1"
}

zNode connection over TLS.

This example instructs Vault to connect to Zookeeper using the provided TLS configuration. The host verification will happen with the presented certificate using the servers IP because 'tls_verify_ip' is set to true.

storage "zookeeper" {
  address = "host1.com:5200,host2.com:5200,host3.com:5200"
  path = "vault_path_on_zk/"
  znode_owner = "digest:vault_user:digestvalueforpassword="
  auth_info = "digest:vault_user:thisisthepassword"
  redirect_addr = "http://localhost:8200"
  tls_verify_ip = "true"
  tls_enabled= "true"
  tls_min_version= "tls12"
  tls_cert_file = "/path/to/the/cert/file/zkcert.pem"
  tls_key_file = "/path/to/the/key/file/zkkey.pem"
  tls_skip_verify= "false"
  tls_ca_file= "/path/to/the/ca/file/ca.pem"
}