Scale an app

Fixed replicas, autoscaling on CPU, memory, requests or latency, and scale-to-zero

Goal. api runs two instances, then autoscales between one and three instances on CPU.

Fixed replicas

pier set app api --replicas 2

output


  Changes:
    ~ update app "api" in prod
      replicas: 1 → 2  (scaling — applied immediately)

→  Updated pier.yaml
→  Waiting for infrastructure provisioning...
OK  Infrastructure ready
OK  Updated app "api" in prod

A replica change is applied immediately. The existing container image is reused, so no build is required and the running instance is not rolled.

pier ls apps

output

                                                                                       
 NAME STATUS  REPLICAS AUTOSCALE IMAGE                                    PORT UPDATED 
                                                                                       
 api  running 2/2      -         zot.pier-registry.svc.cluster.local:5... 8080 2m ago

Autoscale

pier set app api --autoscale 1-3 --trigger cpu:70

output


  Changes:
    ~ update app "api" in prod
      replicas: 2 → 0  (scaling — applied immediately)
      autoscale: off → 1-3 on cpu>70   (policy — applied immediately)

→  Updated pier.yaml
→  Waiting for infrastructure provisioning...
OK  Infrastructure ready
OK  Updated app "api" in prod

--autoscale min-max replaces the fixed count (the two are exclusive). Triggers, repeatable: cpu:70, memory:80 (percent of the plan), rps:50 (requests per second per instance), latency:250ms.

Back to fixed

pier set app api --autoscale off --replicas 1

output


  Changes:
    ~ update app "api" in prod
      replicas: 0 → 1  (scaling — applied immediately)
      autoscale: 1-3 on cpu>70 → off   (policy — applied immediately)

→  Updated pier.yaml
→  Waiting for infrastructure provisioning...
OK  Infrastructure ready
OK  Updated app "api" in prod

What changed

pier.yaml

        targets:
          - name: primary
            plan: app-s
            autoscale:
              min: 1
              max: 3
              triggers:
                - type: cpu
                  target: 70

pier set app --stage writes this without applying; pier apply applies it later.

Variations

Scale to zero: --autoscale 0-3 --idle-after 10m stops the last instance after ten minutes without traffic; the next request starts one.
A larger instance instead of more instances: --plan app-m (Plans). A plan change rolls the target.
Per target: pier set app api/canary --replicas 1 scales one target.

Scale an app

Fixed replicas

Autoscale

Back to fixed

What changed

Variations

See also

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