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

layout	page_title	sidebar_current	description
docs	Commands: Exec	docs-commands-exec	The exec command provides a mechanism for remote execution. For example, this can be used to run the `uptime` command across all machines providing the `web` service.

Consul Exec

Command: consul exec

The exec command provides a mechanism for remote execution. For example, this can be used to run the uptime command across all machines providing the web service.

Remote execution works by specifying a job, which is stored in the KV store. Agents are informed about the new job using the event system, which propagates messages via the gossip protocol. As a result, delivery is best-effort, and there is no guarantee of execution.

While events are purely gossip driven, remote execution relies on the KV store as a message broker. As a result, the exec command will not be able to properly function during a Consul outage.

Usage

Usage: consul exec [options] [-|command...]

The only required option is a command to execute. This is either given as trailing arguments, or by specifying '-'; stdin will be read to completion as a script to evaluate.

The list of available flags are:

• -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.

• -datacenter - Datacenter to query. Defaults to that of agent. In version 0.4, that is the only supported value.

• -prefix - Key prefix in the KV store to use for storing request data. Defaults to "_rexec".

• -node - Regular expression to filter nodes which should evaluate the event.

• -service - Regular expression to filter to only nodes with matching services.

• -tag - Regular expression to filter to only nodes with a service that has a matching tag. This must be used with -service. As an example, you may do "-service mysql -tag slave".

• -wait - Specifies the period of time in which no agent's respond before considering the job finished. This is basically the quiescent time required to assume completion. This period is not a hard deadline, and the command will wait longer depending on various heuristics.

• -wait-repl - Period to wait after writing the job specification for replication. This is a heuristic value and enables agents to do a stale read of the job. Defaults to 200msec.

• -verbose - Enables verbose output.

• -token - The ACL token to use during requests. This token must have access to the prefix in the KV store as well as exec "write" access for the _rexec event. Defaults to that of the agent.