scaling block in the job specification

The scaling block allows configuring scaling options for a task or a group, for the purpose of supporting external autoscalers like the Nomad Autoscaler and scaling via the Nomad UI. This block is not supported within jobs of type system.

When placed at the group level, the scaling policy will be of type horizontal application scaling, controlling the value of count for the group.

job "example" {
  datacenters = ["dc1"]

  group "cache" {
    count = 1

    scaling {
      enabled = true
      min     = 0
      max     = 10

      policy {
        # ...
      }
    }
    # ...
  }
}

When placed at the task level, the scaling policy will be of type Dynamic Application Sizing, controlling the resources values of the task. In this scenario, the scaling block must have a label indicating which resource will be controlled. Valid names are cpu and mem.

job "example" {
  datacenters = ["dc1"]

  group "cache" {
    task "redis" {
      driver = "docker"

      config {
        image = "redis:7"
      }

      resources {
        cpu    = 100
        memory = 256
      }

      scaling "cpu" {
        enabled = true
        min     = 100
        max     = 500

        policy {
          # ...
        }
      }

      scaling "mem" {
        enabled = true
        min     = 64
        max     = 512

        policy {
          # ...
        }
      }
    }
  }
}

Parameters

• min - (int: nil) - The minimum acceptable count for the task group. This should be honored by the external autoscaler. It will also be honored by Nomad during job updates and scaling operations. Defaults to the specified task group count.

• max - (int: <required>) - The maximum acceptable count for the task group. This should be honored by the external autoscaler. It will also be honored by Nomad during job updates and scaling operations.

• enabled - (bool: false) - Whether the scaling policy is enabled. This is intended to allow temporarily disabling an autoscaling policy, and should be honored by the external autoscaler.

• policy - (map<string|...>: nil) - The autoscaling policy. This is opaque to Nomad, consumed and parsed only by the external autoscaler. Therefore, its contents are specific to the autoscaler; consult the Nomad Autoscaler documentation for more details.