Explain Openshift resource manifest

[Chetan_Tiwary_]

Explain this openshift resource manifest

apiVersion: autoscaling/v2beta2
kind: HorizontalPodAutoscaler
metadata:
  name: hpa-resource-metrics-memory
  namespace: default
spec:
...
  minReplicas: 20
...
  behavior:
    scaleDown:
      stabilizationWindowSeconds: 300
      policies:
      - type: Pods
        value: 4
        periodSeconds: 30
      - type: Percent
        value: 10
        periodSeconds: 60
      selectPolicy: Max
    scaleUp:
      selectPolicy: Disabled

[lintang404]

This OpenShift Horizontal Pod Autoscaler (HPA) manifest automatically adjusts the number of pod replicas based on resource metrics like memory usage.

Explanation:

• apiVersion: Specifies the HPA API version (autoscaling/v2beta2), which supports advanced scaling policies.
• kind: Defines the resource type as HorizontalPodAutoscaler.
• metadata: Contains metadata such as the HPA name and namespace.
• minReplicas: Sets the minimum number of pods to 20 (the cluster will never scale below this number).
• behavior: Controls how the HPA scales pods:

Scale Down Policy:

• stabilizationWindowSeconds: Waits 300 seconds (5 minutes) before scaling down to avoid frequent fluctuations.
• policies: Defines two methods for scaling down:
  • Pods Type: Remove up to 4 pods every 30 seconds.
  • Percent Type: Remove 10% of pods every 60 seconds.
• selectPolicy: Chooses the Max policy, meaning the most aggressive scaling policy will be applied.

Scale Up Policy:

• selectPolicy: Set to Disabled, which means pods will not scale up automatically.
  
  Summary
  This HPA automatically scales down pods based on memory usage, with a minimum of 20 pods. It removes pods gradually to avoid sudden changes, prioritizing the fastest possible scale-down method. Scaling up is completely disabled.

[afordona]

Summary of the OpenShift manifest for the HorizontalPodAutoscaler (HPA):

Minimum Replicas: Ensures at least 20 pod replicas are maintained.
Scale Down Behavior:
Stabilization window of 300 seconds.
Policies to scale down by a maximum of 4 pods every 30 seconds or 10% every 60 seconds.
Uses the policy with the maximum value.
Scale Up Behavior: Scaling up is disabled,

[Asma-Alfayyad]

This manifest defines a HorizontalPodAutoscaler to automatically scale the number of pod replicas based on resource usage, in this case, memory.

• The HorizontalPodAutoscaler ensures at least 20 replicas are running at all times.
• When scaling down, it allows reductions of up to 4 pods in 30 seconds and 10% of the total pods in 1 minute, but it won’t scale down too quickly (due to the 5-minute stabilization window).
• Scaling up is disabled in this configuration, meaning the system won't automatically add more pods based on memory usage.