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| 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.
Verbose output warning: use care to make sure that your command does not produce a large volume of output. Writes to the KV store for this output go through the Consul servers and the Raft consensus algorithm, so having a large number of nodes in the cluster flow a large amount of data through the KV store could make the cluster unavailable.
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.