--- layout: "docs" page_title: "Server Configuration" sidebar_current: "docs-config" description: |- Vault server configuration reference. --- # Server Configuration Outside of development mode, Vault servers are configured using a file. The format of this file is [HCL](https://github.com/hashicorp/hcl) or JSON. An example configuration is shown below: ```javascript backend "consul" { address = "127.0.0.1:8500" path = "vault" } listener "tcp" { address = "127.0.0.1:8200" tls_disable = 1 } telemetry { statsite_address = "127.0.0.1:8125" disable_hostname = true } ``` After the configuration is written, use the `-config` flag with `vault server` to specify where the configuration is. ## Reference * `backend` (required) - Configures the storage backend where Vault data is stored. There are multiple options available for storage backends, and they're documented below. * `ha_backend` (optional) - Configures the storage backend where Vault HA coordination will take place. Must be an HA-supporting backend using the configuration options as documented below. If not set, HA will be attempted on the backend given in the `backend` parameter. * `listener` (required) - Configures how Vault is listening for API requests. "tcp" is currently the only option available. A full reference for the inner syntax is below. * `disable_cache` (optional) - A boolean. If true, this will disable the read cache used by the physical storage subsystem. This will very significantly impact performance. * `disable_mlock` (optional) - A boolean. If true, this will disable the server from executing the `mlock` syscall to prevent memory from being swapped to disk. This is not recommended in production (see below). * `telemetry` (optional) - Configures the telemetry reporting system (see below). * `default_lease_ttl` (optional) - Configures the default lease duration for tokens and secrets, specified in hours. Default value is 30 days. This value cannot be larger than `max_lease_ttl`. * `max_lease_ttl` (optional) - Configures the maximum possible lease duration for tokens and secrets, specified in hours. Default value is 30 days. In production, you should only consider setting the `disable_mlock` option on Linux systems that only use encrypted swap or do not use swap at all. Vault does not currently support memory locking on Mac OS X and Windows and so the feature is automatically disabled on those platforms. To give the Vault executable access to the `mlock` syscall on Linux systems: ```shell sudo setcap cap_ipc_lock=+ep $(readlink -f $(which vault)) ``` ## Listener Reference For the `listener` section, the only supported listener currently is "tcp". Regardless of future plans, this is the recommended listener, since it allows for HA mode. The supported options are: * `address` (optional) - The address to bind to for listening. This defaults to "127.0.0.1:8200". * `tls_disable` (optional) - If true, then TLS will be disabled. This will parse as boolean value, and can be set to "0", "no", "false", "1", "yes", or "true". This is an opt-in; Vault assumes by default that TLS will be used. * `tls_cert_file` (required unless disabled) - The path to the certificate for TLS. * `tls_key_file` (required unless disabled) - The path to the private key for the certificate. * `tls_min_version` (optional) - **(Vault > 0.2)** If provided, specifies the minimum supported version of TLS. Accepted values are "tls10", "tls11" or "tls12". This defaults to "tls12". WARNING: TLS 1.1 and lower are generally considered less secure; avoid using these if possible. ## Telemetry Reference For the `telemetry` section, there is no resource name. All configuration is within the object itself. * `statsite_address` (optional) - An address to a [Statsite](https://github.com/armon/statsite) instances for metrics. This is highly recommended for production usage. * `statsd_address` (optional) - This is the same as `statsite_address` but for StatsD. * `disable_hostname` (optional) - Whether or not to prepend runtime telemetry with the machines hostname. This is a global option. Defaults to false. ## Backend Reference For the `backend` section, the supported physical backends are shown below. Vault requires that the backend itself will be responsible for backups, durability, etc. __*Please note*__: The only physical backends actively maintained by HashiCorp are `consul`, `inmem`, and `file`. The other backends are community-derived and community-supported. We include them in the hope that they will be useful to those users that wish to utilize them, but they receive minimal validation and testing from HashiCorp, and HashiCorp staff may not be knowledgeable about the data store being utilized. If you encounter problems with them, we will attempt to help you, but may refer you to the backend author. * `consul` - Store data within [Consul](https://www.consul.io). This backend supports HA. It is the most recommended backend for Vault and has been shown to work at high scale under heavy load. * `etcd` - Store data within [etcd](https://coreos.com/etcd/). This backend supports HA. This is a community-supported backend. * `zookeeper` - Store data within [Zookeeper](https://zookeeper.apache.org/). This backend supports HA. This is a community-supported backend. * `dynamodb` - Store data in a [DynamoDB](https://aws.amazon.com/dynamodb/) table. This backend supports HA. This is a community-supported backend. * `s3` - Store data within an S3 bucket [S3](https://aws.amazon.com/s3/). This backend does not support HA. This is a community-supported backend. * `mysql` - Store data within MySQL. This backend does not support HA. This is a community-supported backend. * `inmem` - Store data in-memory. This is only really useful for development and experimentation. Data is lost whenever Vault is restarted. * `file` - Store data on the filesystem using a directory structure. This backend does not support HA. #### Common Backend Options All backends support the following options: * `advertise_addr` (optional) - For backends that support HA, this is the address to advertise to other Vault servers in the cluster for request forwarding. Most HA backends will attempt to determine the advertise address if not provided. This can also be set via the `VAULT_ADVERTISE_ADDR` environment variable. #### Backend Reference: Consul For Consul, the following options are supported: * `path` (optional) - The path within Consul where data will be stored. Defaults to "vault/". * `address` (optional) - The address of the Consul agent to talk to. Defaults to the local agent address, if available. * `scheme` (optional) - "http" or "https" for talking to Consul. * `token` (optional) - An access token to use to write data to Consul. * `max_parallel` (optional) - The maximum number of connections to Consul; defaults to "128". * `tls_skip_verify` (optional) - If non-empty, then TLS host verification will be disabled for Consul communication. Defaults to false. The following settings should be set according to your [Consul encryption settings](https://www.consul.io/docs/agent/encryption.html): * `tls_ca_file` (optional) - The path to the CA certificate used for Consul communication. Defaults to system bundle if not specified. Set accordingly to the [ca_file](https://www.consul.io/docs/agent/options.html#ca_file) setting in Consul. * `tls_cert_file` (optional) - The path to the certificate for Consul communication. Set accordingly to the [cert_file](https://www.consul.io/docs/agent/options.html#cert_file) setting in Consul. * `tls_key_file` (optional) - The path to the private key for Consul communication. Set accordingly to the [key_file](https://www.consul.io/docs/agent/options.html#key_file) setting in Consul. #### Backend Reference: etcd (Community-Supported) For etcd, the following options are supported: * `path` (optional) - The path within etcd where data will be stored. Defaults to "vault/". * `address` (optional) - The address(es) of the etcd instance(s) to talk to. Can be comma separated list (protocol://host:port) of many etcd instances. Defaults to "http://localhost:2379" if not specified. * `tls_ca_file` (optional) - The path to the CA certificate used for etcd communication. Defaults to system bundle if not specified. * `tls_cert_file` (optional) - The path to the certificate for etcd communication. * `tls_key_file` (optional) - The path to the private key for etcd communication. #### Backend Reference: Zookeeper (Community-Supported) For Zookeeper, the following options are supported: * `path` (optional) - The path within Zookeeper where data will be stored. Defaults to "vault/". * `address` (optional) - The address(es) of the Zookeeper instance(s) to talk to. Can be comma separated list (host:port) of many Zookeeper instances. Defaults to "localhost:2181" if not specified. #### Backend Reference: DynamoDB (Community-Supported) The DynamoDB backend has the following options: * `table` (optional) - The name of the DynamoDB table to store data in. The default table name is `vault-dynamodb-backend`. This option can also be provided via the environment variable `AWS_DYNAMODB_TABLE`. If the specified table does not yet exist, it will be created during initialization. * `read_capacity` (optional) - The read capacity to provision when creating the DynamoDB table. This is the maximum number of reads consumed per second on the table. The default value is 5. This option can also be provided via the environment variable `AWS_DYNAMODB_READ_CAPACITY`. * `write_capacity` (optional) - The write capacity to provision when creating the DynamoDB table. This is the maximum number of writes performed per second on the table. The default value is 5. This option can also be provided via the environment variable `AWS_DYNAMODB_WRITE_CAPACITY`. * `access_key` - (required) The AWS access key. It must be provided, but it can also be sourced from the `AWS_ACCESS_KEY_ID` environment variable. * `secret_key` - (required) The AWS secret key. It must be provided, but it can also be sourced from the `AWS_SECRET_ACCESS_KEY` environment variable. * `session_token` - (optional) The AWS session token. It can also be sourced from the `AWS_SESSION_TOKEN` environment variable. * `endpoint` - (optional) An alternative (AWS compatible) DynamoDB endpoint to use. It can also be sourced from the `AWS_DYNAMODB_ENDPOINT` environment variable. * `region` (optional) - The AWS region. It can be sourced from the `AWS_DEFAULT_REGION` environment variable and will default to "us-east-1" if not specified. * `recovery_mode` (optional) - When the Vault leader crashes or is killed without being able to shut down properly, no other node can become the new leader because the DynamoDB table still holds the old leader's lock record. To recover from this situation, one can start a single Vault node with this option set to `1` and the node will remove the old lock from DynamoDB. It is important that only one node is running in recovery mode! After this node has become the leader, other nodes can be started with regular configuration. This option can also be provided via the environment variable `RECOVERY_MODE`. For more information about the read/write capacity of DynamoDB tables, see the [official AWS DynamoDB docs](https://docs.aws.amazon.com/amazondynamodb/latest/developerguide/WorkingWithTables.html#ProvisionedThroughput). If you are running your Vault server on an EC2 instance, you can also make use of the EC2 instance profile service to provide the credentials Vault will use to make DynamoDB API calls. Leaving the `access_key` and `secret_key` fields empty will cause Vault to attempt to retrieve credentials from the metadata service. #### Backend Reference: S3 (Community-Supported) For S3, the following options are supported: * `bucket` (required) - The name of the S3 bucket to use. It must be provided, but it can also be sourced from the `AWS_S3_BUCKET` environment variable. * `access_key` - (required) The AWS access key. It must be provided, but it can also be sourced from the `AWS_ACCESS_KEY_ID` environment variable. * `secret_key` - (required) The AWS secret key. It must be provided, but it can also be sourced from the `AWS_SECRET_ACCESS_KEY` environment variable. * `session_token` - (optional) The AWS session token. It can also be sourced from the `AWS_SESSION_TOKEN` environment variable. * `endpoint` - (optional) An alternative (AWS compatible) S3 endpoint to use. It can also be sourced from the `AWS_S3_ENDPOINT` environment variable. * `region` (optional) - The AWS region. It can be sourced from the `AWS_DEFAULT_REGION` environment variable and will default to "us-east-1" if not specified. If you are running your Vault server on an EC2 instance, you can also make use of the EC2 instance profile service to provide the credentials Vault will use to make S3 API calls. Leaving the `access_key` and `secret_key` fields empty will cause Vault to attempt to retrieve credentials from the metadata service. You are responsible for ensuring your instance is launched with the appropriate profile enabled. Vault will handle renewing profile credentials as they rotate. #### Backend Reference: MySQL (Community-Supported) The MySQL backend has the following options: * `username` (required) - The MySQL username to connect with. * `password` (required) - The MySQL password to connect with. * `address` (optional) - The address of the MySQL host. Defaults to "127.0.0.1:3306. * `database` (optional) - The name of the database to use. Defaults to "vault". * `table` (optional) - The name of the table to use. Defaults to "vault". * `tls_ca_file` (optional) - The path to the CA certificate to connect using TLS #### Backend Reference: PostgreSQL (Community-Supported) The PostgreSQL backend has the following options: * `connection_url` (required) - The connection string used to connect to PostgreSQL. Examples: * postgres://username:password@localhost:5432/database?sslmode=disabled * postgres://username:password@localhost:5432/database?sslmode=verify-full A list of all supported parameters can be found in [the pq library documentation](https://godoc.org/github.com/lib/pq#hdr-Connection_String_Parameters). * `table` (optional) - The name of the table to write vault data to. Defaults to "vault". * `upsert_function` (optional) - The name of the upsert function. Defaults to "vault_upsert". *This will only be used if you're running a version of PostgreSQL prior to 9.5* Make sure the PostgreSQL database you choose (or create) for vault storage has a table suitable for storing vault's data: ```sql CREATE TABLE vault ( vault_key TEXT PRIMARY KEY, vault_value BYTEA ); ``` If you're using a version of PostgreSQL prior to 9.5, create an upsert function in the database you will be using for vault storage (taken from [PostgreSQL documentation](http://www.postgresql.org/docs/9.4/static/plpgsql-control-structures.html#PLPGSQL-UPSERT-EXAMPLE): ```sql CREATE FUNCTION vault_upsert(_key TEXT, _value BYTEA) RETURNS VOID AS $$ BEGIN LOOP -- first try to update the key UPDATE vault SET vault_value = _value WHERE vault_key = _key; IF found THEN RETURN; END IF; -- not there, so try to insert the key -- if someone else inserts the same key concurrently, -- we could get a unique-key failure BEGIN INSERT INTO vault (vault_key, vault_value) VALUES (_key, _value); RETURN; EXCEPTION WHEN unique_violation THEN -- Do nothing, and loop to try the UPDATE again. END; END LOOP; END; $$ LANGUAGE plpgsql; ``` #### Backend Reference: Inmem The in-memory backend has no configuration options. #### Backend Reference: File The file backend has the following options: * `path` (required) - The path on disk to a directory where the data will be stored.