Integrated Storage (Raft) Backend

The Integrated Storage backend is used to persist Vault's data. Unlike other storage backends, Integrated Storage does not operate from a single source of data. Instead all the nodes in a Vault cluster will have a replicated copy of Vault's data. Data gets replicated across all the nodes via the Raft Consensus Algorithm.

• High Availability – the Integrated Storage backend supports high availability.

• HashiCorp Supported – the Integrated Storage backend is officially supported by HashiCorp.

storage "raft" {
  path = "/path/to/raft/data"
  node_id = "raft_node_1"
}
cluster_addr = "http://127.0.0.1:8201"

raft Parameters

• path (string: "") – The file system path where all the Vault data gets stored. This value can be overridden by setting the VAULT_RAFT_PATH environment variable.

• node_id (string: "") - The identifier for the node in the Raft cluster. This value can be overridden by setting the VAULT_RAFT_NODE_ID environment variable.

• performance_multiplier (integer: 0) - An integer multiplier used by servers to scale key Raft timing parameters. Tuning this affects the time it takes Vault to detect leader failures and to perform leader elections, at the expense of requiring more network and CPU resources for better performance. Omitting this value or setting it to 0 uses default timing described below. Lower values are used to tighten timing and increase sensitivity while higher values relax timings and reduce sensitivity.

  By default, Vault will use a lower-performance timing that's suitable for minimal Vault servers, currently equivalent to setting this to a value of 5 (this default may be changed in future versions of Vault, depending if the target minimum server profile changes). Setting this to a value of 1 will configure Raft to its highest-performance mode and is recommended for production Vault servers. The maximum allowed value is 10.

• trailing_logs (integer: 10000) - This controls how many log entries are left in the log store on disk after a snapshot is made. This should only be adjusted when followers cannot catch up to the leader due to a very large snapshot size and high write throughput causing log truncation before a snapshot can be fully installed. If you need to use this to recover a cluster, consider reducing write throughput or the amount of data stored on Vault. The default value is 10000 which is suitable for all normal workloads.

• snapshot_threshold (integer: 8192) - This controls the minimum number of Raft commit entries between snapshots that are saved to disk. This is a low-level parameter that should rarely need to be changed. Very busy clusters experiencing excessive disk IO may increase this value to reduce disk IO and minimize the chances of all servers taking snapshots at the same time. Increasing this trades off disk IO for disk space since the log will grow much larger and the space in the raft.db file can't be reclaimed till the next snapshot. Servers may take longer to recover from crashes or failover if this is increased significantly as more logs will need to be replayed.

• retry_join (list: []) - There can be one or more retry_join stanzas. When the Raft cluster is getting bootstrapped, if the connection details of all the nodes are known beforehand, then specifying this config stanzas enables the nodes to automatically join a Raft cluster. All the nodes would mention all other nodes that they could join using this config. When one of the nodes is initialized, it becomes the leader and all the other nodes will join the leader node to form the cluster. When using Shamir seal, the joined nodes will still need to be unsealed manually. See the section below that describes the parameters accepted by the retry_join stanza.

• max_entry_size (integer: 1048576) - This configures the maximum number of bytes for a Raft entry. It applies to both Put operations and transactions. Any put or transaction operation exceeding this configuration value will cause the respective operation to fail. Raft has a suggested max size of data in a Raft log entry. This is based on current architecture, default timing, etc. Integrated Storage also uses a chunk size that is the threshold used for breaking a large value into chunks. By default, the chunk size is the same as Raft's max size log entry. The default value for this configuration is 1048576 -- two times the chunking size.

• autopilot_reconcile_interval (string: "10s") - This is the interval after which autopilot will pick up any state changes. State change could mean multiple things; for example a newly joined voter node, initially added as non-voter to the Raft cluster by autopilot has successfully completed the stabilization period thereby qualifying for being promoted as a voter, a node that has become unhealthy and needs to be shown as such in the state API, a node has been marked as dead needing eviction from Raft configuration, etc.

retry_join stanza

• leader_api_addr (string: "") - Address of a possible leader node.

• auto_join (string: "") - Cloud auto-join configuration, using go-discover syntax.

• auto_join_scheme (string: "") - The optional URI protocol scheme for addresses discovered via auto-join. Available values are http or https.

• auto_join_port (uint: "") - The optional port used for addressed discovered via auto-join.

• leader_tls_servername (string: "") - The TLS server name to use when connecting with HTTPS. Should match one of the names in the DNS SANs of the remote server certificate. See also Integrated Storage and TLS

• leader_ca_cert_file (string: "") - File path to the CA cert of the possible leader node.

• leader_client_cert_file (string: "") - File path to the client certificate for the follower node to establish client authentication with the possible leader node.

• leader_client_key_file (string: "") - File path to the client key for the follower node to establish client authentication with the possible leader node.

• leader_ca_cert (string: "") - CA cert of the possible leader node.

• leader_client_cert (string: "") - Client certificate for the follower node to establish client authentication with the possible leader node.

• leader_client_key (string: "") - Client key for the follower node to establish client authentication with the possible leader node.

Each retry_join block may provide TLS certificates via file paths or as a single-line certificate string value with newlines delimited by \n, but not a combination of both. Each retry_join stanza may contain either a leader_api_addr value or a cloud auto_join configuration value, but not both. When an auto_join value is provided, Vault will automatically attempt to discover and resolve potential Raft leader addresses using go-discover. See the go-discover README for details on the format of the auto_join value.

By default, Vault will attempt to reach discovered peers using HTTPS and port 8200. Operators may override these through the auto_join_scheme and auto_join_port fields respectively.

Example Configuration:

storage "raft" {
  path    = "/Users/foo/raft/"
  node_id = "node1"

  retry_join {
    leader_api_addr = "http://127.0.0.2:8200"
    leader_ca_cert_file = "/path/to/ca1"
    leader_client_cert_file = "/path/to/client/cert1"
    leader_client_key_file = "/path/to/client/key1"
  }
  retry_join {
    leader_api_addr = "http://127.0.0.3:8200"
    leader_ca_cert_file = "/path/to/ca2"
    leader_client_cert_file = "/path/to/client/cert2"
    leader_client_key_file = "/path/to/client/key2"
  }
  retry_join {
    leader_api_addr = "http://127.0.0.4:8200"
    leader_ca_cert_file = "/path/to/ca3"
    leader_client_cert_file = "/path/to/client/cert3"
    leader_client_key_file = "/path/to/client/key3"
  }
  retry_join {
    auto_join = "provider=aws region=eu-west-1 tag_key=vault tag_value=... access_key_id=... secret_access_key=..."
  }
}

Tutorial

Refer to the Integrated Storage series of tutorials to learn more about implementing Vault using Integrated Storage.