consul/website/source/docs/commands/rtt.html.markdown

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docs	Commands: RTT	docs-commands-rtt	The rtt command estimates the network round trip time between two nodes.

Consul RTT

Command: consul rtt

The rtt command estimates the network round trip time between two nodes using Consul's network coordinate model of the cluster.

See the Network Coordinates internals guide for more information on how these coordinates are computed.

Usage

Usage: consul rtt [options] node1 [node2]

At least one node name is required. If the second node name isn't given, it is set to the agent's node name. These are the node names as known to Consul as the consul members command would show, not IP addresses.

The list of available flags are:

• -wan - Instructs the command to use WAN coordinates instead of LAN coordinates. By default, the two nodes are assumed to be nodes in the local datacenter and the LAN coordinates are used. If the -wan option is given, then the WAN coordinates are used, and the node names must be suffixed by a period and the datacenter (eg. "myserver.dc1"). It is not possible to measure between LAN coordinates and WAN coordinates, so both nodes must be in the same pool.

• -http-addr - Address to the HTTP server of the agent you want to contact to send this command. If this isn't specified, the command will contact "127.0.0.1:8500" which is the default HTTP address of a Consul agent.

The following environment variables control accessing the HTTP server via SSL:

• CONSUL_HTTP_SSL Set this to enable SSL
• CONSUL_HTTP_SSL_VERIFY Set this to disable certificate checking (not recommended)

Output

If coordinates are available, the command will print the estimated round trip time between the given nodes:

$ consul rtt n1 n2
Estimated n1 <-> n2 rtt: 0.610 ms (using LAN coordinates)

$ consul rtt n2 # Running from n1
Estimated n1 <-> n2 rtt: 0.610 ms (using LAN coordinates)

$ consul rtt -wan n1.dc1 n2.dc2
Estimated n1.dc1 <-> n2.dc2 rtt: 1.275 ms (using WAN coordinates)