116 lines
3.1 KiB
Plaintext
116 lines
3.1 KiB
Plaintext
---
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layout: docs
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page_title: scaling Stanza - Job Specification
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description: The "scaling" stanza allows specifying scaling policy for a task group
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---
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# `scaling` Stanza
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<Placement
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groups={[
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['job', 'group', 'scaling'],
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['job', 'group', 'task', 'scaling'],
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]}
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/>
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The `scaling` block allows configuring scaling options for a `task` or a
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`group`, for the purpose of supporting external autoscalers like the
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[Nomad Autoscaler](https://github.com/hashicorp/nomad-autoscaler) and scaling
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via the Nomad UI. This stanza is not supported within jobs of type `system`.
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When placed at the `group` level, the scaling policy will be of type
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[horizontal application scaling][horizontal_app_scaling], controlling the value
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of [`count`][] for the group.
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```hcl
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job "example" {
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datacenters = ["dc1"]
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group "cache" {
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count = 1
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scaling {
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enabled = true
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min = 0
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max = 10
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policy {
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# ...
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}
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}
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# ...
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}
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}
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```
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When placed at the `task` level, the scaling policy will be of type
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[Dynamic Application Sizing][das], controlling the [`resources`][] values of
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the task. In this scenario, the `scaling` block must have a label indicating
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which resource will be controlled. Valid names are `cpu` and `mem`.
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```hcl
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job "example" {
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datacenters = ["dc1"]
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group "cache" {
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task "redis" {
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driver = "docker"
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config {
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image = "redis:7"
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}
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resources {
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cpu = 100
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memory = 256
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}
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scaling "cpu" {
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enabled = true
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min = 100
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max = 500
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policy {
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# ...
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}
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}
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scaling "mem" {
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enabled = true
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min = 64
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max = 512
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policy {
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# ...
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}
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}
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}
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}
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}
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```
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## `scaling` Parameters
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- `min` - <code>(int: nil)</code> - The minimum acceptable count for the task group.
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This should be honored by the external autoscaler. It will also be honored by Nomad
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during job updates and scaling operations. Defaults to the specified task group [`count`][].
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- `max` - <code>(int: <required>)</code> - The maximum acceptable count for the task group.
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This should be honored by the external autoscaler. It will also be honored by Nomad
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during job updates and scaling operations.
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- `enabled` - <code>(bool: false)</code> - Whether the scaling policy is enabled.
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This is intended to allow temporarily disabling an autoscaling policy, and should be
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honored by the external autoscaler.
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- `policy` - <code>(map<string|...>: nil)</code> - The autoscaling policy. This is
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opaque to Nomad, consumed and parsed only by the external autoscaler. Therefore,
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its contents are specific to the autoscaler; consult the
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[Nomad Autoscaler documentation][autoscaling_policy] for more details.
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[autoscaling_policy]: /tools/autoscaling/policy
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[`count`]: /docs/job-specification/group#count 'Nomad Task Group specification'
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[`resources`]: /docs/job-specification/task#resources 'Nomad Task specification'
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[das]: /tools/autoscaling#dynamic-application-sizing
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[horizontal_app_scaling]: /tools/autoscaling#horizontal-application-autoscaling
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