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»Consul Join

Command: consul join

Corresponding HTTP API Endpoint: [PUT] /v1/agent/join/:address

The join command tells a Consul agent to join an existing cluster. A new Consul agent may join any node in the existing cluster. After joining with one member, the gossip communication will propagate the updated membership state across the cluster.

An agent which is already part of a cluster may join an agent in a different cluster, causing the two clusters to be merged into a single cluster.

The table below shows this command's required ACLs. Configuration of blocking queries and agent caching are not supported from commands, but may be from the corresponding HTTP endpoint.

ACL Required
agent:write

»Usage

Usage: consul join [options] address ...

You may call join with multiple addresses if you want attempt to join the cluster through multiple nodes. Consul will attempt to join all addresses. The join command will fail only if Consul was unable to join any of the specified addresses.

»API Options

  • -ca-file=<value> - Path to a CA file to use for TLS when communicating with Consul. This can also be specified via the CONSUL_CACERT environment variable.

  • -ca-path=<value> - Path to a directory of CA certificates to use for TLS when communicating with Consul. This can also be specified via the CONSUL_CAPATH environment variable.

  • -client-cert=<value> - Path to a client cert file to use for TLS when verify_incoming is enabled. This can also be specified via the CONSUL_CLIENT_CERT environment variable.

  • -client-key=<value> - Path to a client key file to use for TLS when verify_incoming is enabled. This can also be specified via the CONSUL_CLIENT_KEY environment variable.

  • -http-addr=<addr> - Address of the Consul agent with the port. This can be an IP address or DNS address, but it must include the port. This can also be specified via the CONSUL_HTTP_ADDR environment variable. In Consul 0.8 and later, the default value is http://127.0.0.1:8500, and https can optionally be used instead. The scheme can also be set to HTTPS by setting the environment variable CONSUL_HTTP_SSL=true. This may be a unix domain socket using unix:///path/to/socket if the agent is configured to listen that way.

  • -tls-server-name=<value> - The server name to use as the SNI host when connecting via TLS. This can also be specified via the CONSUL_TLS_SERVER_NAME environment variable.

  • -token=<value> - ACL token to use in the request. This can also be specified via the CONSUL_HTTP_TOKEN environment variable. If unspecified, the query will default to the token of the Consul agent at the HTTP address.

  • -token-file=<value> - File containing the ACL token to use in the request instead of one specified via the -token argument or CONSUL_HTTP_TOKEN environment variable. This can also be specified via the CONSUL_HTTP_TOKEN_FILE environment variable.

»Command Options

  • -wan - For agents running in server mode, the agent will attempt to join other servers gossiping in a WAN cluster. This is used to form a bridge between multiple datacenters.