Scale StatefulSet

Use this action to up or downscale a Kubernetes StatefulSet. The attack scales the StatefulSet to the specified replica count at the beginning of the attack and rolls it back to the old replica count whenever the attack stops. Intermediate changes of the replica count, i.e., by third-party tools, don't cause a re-scaling by the attack.

Use Cases

Verify that your StatefulSet is successfully scaled up and the new pod is taken into account by your load balancer
Check how long it takes to scale your StatefulSet to a desirable amount of pods

Parameters

Name	Required	Description	Default
Duration	true	How long should the new scale be used?	180s
Replica Count	true	The desired replica count	1

Rollback

The old desired replica count will be restored after the action has ended.

Useful Templates

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Keep StatefulSet's pods down

Check what happens when all pods of a Kubernetes StatefulSet aren't coming up again.

Motivation

Typically, Kubernetes tries to keep as many pods running as desired for a Kubernetes StatefulSet. However, some circumstances may prevent Kubernetes from achieving this, like missing resources in the cluster, problems with the StatefulSet's probes, or a CrashLoopBackOff. You should validate what happens to your upstream services that are using the given StatefulSet as a downstream service.

Structure

To keep the pods down for a given StatefulSet, we first kill all the pods in the StatefulSet. Simultaneously, we will scale down the Kubernetes StatefulSet to 0 to simulate that these pods can't be scheduled again. At the of the experiment, we automatically roll back the StatefulSet's scale to the initial value.