» Consul Join

Command: consul join

The join command tells a Consul agent to join an existing cluster. A new Consul agent must join with at least one existing member of a cluster in order to join an existing cluster. After joining that one member, the gossip layer takes over, propagating the updated membership state across the cluster.

If you don't join an existing cluster, then that agent is part of its own isolated cluster. Other nodes can join it.

Agents can join other agents multiple times without issue. If a node that is already part of a cluster joins another node, then the clusters of the two nodes join to become a single cluster.

» Usage

Usage: consul join [options] address ...

You may call join with multiple addresses if you want to try to join multiple clusters. Consul will attempt to join all addresses, and the join command will fail only if Consul was unable to join with any.

» 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.

» 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.