Node parameters for Consul agent configuration files

The page provides reference information for node parameters in a Consul agent configuration file.

Node Parameters

• node_id - Specifies a unique identifier for this node across all time, even if the name of the node or address changes. This must be in the form of a hex string, 36 characters long, such as adf4238a-882b-9ddc-4a9d-5b6758e4159e. If this isn't supplied, which is the most common case, then the agent will generate an identifier at startup and persist it in the data directory so that it will remain the same across agent restarts. Information from the host will be used to generate a deterministic node ID if possible, unless disable-host-node-id is set to true.

• node_name - The name of this node in the cluster. This name must be unique within the cluster. By default, it assumes the hostname of the machine. The node name cannot contain whitespace or quotation marks. To query the node from DNS, the name must only contain alphanumeric characters and hyphens (-). Equivalent to the -node command-line flag.

• node_meta This object allows associating arbitrary metadata key/value pairs with the local node, which can then be used for filtering results from certain catalog endpoints. Refer to the -node-meta command-line flag for more information.

• disable_host_node_id - Set this parameter to true to prevent Consul from using information from the host to generate a deterministic node ID. Instead, Consul generates a random node ID that it persists in the data directory. This parameter is useful when running multiple Consul agents on the same host for testing. The default value is false, so you must opt-in for host-based IDs. Host-based IDs are generated using gopsutil, which is shared with HashiCorp Nomad, so if you opt-in to host-based IDs, then Consul and Nomad will use information on the host to automatically assign the same ID in both systems. Equivalent to the -disable-host-node-id command-line flag.

Examples

Node meta

This example illustrates node_meta configuration.

node_meta {
  instance_type = "t2.medium"
}

{
  "node_meta": {
    "instance_type": "t2.medium"
  }
}