2020-07-01 11:03:49 +00:00
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---
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layout: docs
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page_title: Checks
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sidebar_title: Checks
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description: Learn about how the Autoscaler deals with policy checks.
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---
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# Nomad Autoscaler Check Calculations
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A scaling policy can include several checks all of which produce a scaling
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suggesting. The checks are executed at the same time during a policy evaluation
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and the results can conflict with each other. In a scenario like this, the
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autoscaler iterates the results the chooses the safest result which results in
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retaining the most capacity of the resource.
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In a scenario where two checks return different desired directions, the following
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logic is applied.
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2020-09-30 13:48:40 +00:00
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- `ScaleOut and ScaleIn => ScaleOut`
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2020-07-01 11:03:49 +00:00
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- `ScaleOut and ScaleNone => ScaleOut`
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2020-09-30 13:48:40 +00:00
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- `ScaleIn and ScaleNone => ScaleNone`
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2020-07-01 11:03:49 +00:00
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In situations where the two same actions are suggested, but with different counts the
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following logic is applied, where the count is the absolute desired value.
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- `ScaleOut(10) and ScaleOut(9) => ScaleOut(10)`
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2020-09-30 13:48:40 +00:00
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- `ScaleIn(3) and ScaleIn(4) => ScaleIn(4)`
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