restart Stanza

The restart stanza configures a tasks's behavior on task failure. Restarts happen on the client that is running the task.

job "docs" {
  group "example" {
    restart {
      attempts = 3
      delay    = "30s"
    }
  }
}

If specified at the group level, the configuration is inherited by all tasks in the group. If present on the task, the policy is merged with the restart policy from the encapsulating task group.

For example, assuming that the task group restart policy is:

restart {
  interval = "30m"
  attempts = 2
  delay    = "15s"
  mode     = "fail"
}

and the individual task restart policy is:

restart {
  attempts = 5
}

then the effective restart policy for the task will be:

restart {
  interval = "30m"
  attempts = 5
  delay    = "15s"
  mode     = "fail"
}

restart Parameters

• attempts (int: <varies>) - Specifies the number of restarts allowed in the configured interval. Defaults vary by job type, see below for more information.

• delay (string: "15s") - Specifies the duration to wait before restarting a task. This is specified using a label suffix like "30s" or "1h". A random jitter of up to 25% is added to the delay.

• interval (string: <varies>) - Specifies the duration which begins when the first task starts and ensures that only attempts number of restarts happens within it. If more than attempts number of failures happen, behavior is controlled by mode. This is specified using a label suffix like "30s" or "1h". Defaults vary by job type, see below for more information.

• mode (string: "fail") - Controls the behavior when the task fails more than attempts times in an interval. For a detailed explanation of these values and their behavior, please see the mode values section.

restart Parameter Defaults

The values for many of the restart parameters vary by job type. Here are the defaults by job type:

• The default batch restart policy is:

  restart {
    attempts = 3
    delay    = "15s"
    interval = "24h"
    mode     = "fail"
  }
  

• The default service and system job restart policy is:

  restart {
    interval = "30m"
    attempts = 2
    delay    = "15s"
    mode     = "fail"
  }
  

mode Values

This section details the specific values for the "mode" parameter in the Nomad job specification for constraints. The mode is always specified as a string

restart {
  mode = "..."
}

• "delay" - Instructs the scheduler to delay the next restart until the next interval is reached.

• "fail" - Instructs the scheduler to not attempt to restart the task on failure. This is the default behavior. This mode is useful for non-idempotent jobs which are unlikely to succeed after a few failures. Failed jobs will be restarted according to the reschedule stanza.