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feat: hpa with cpu + mem util scaling options #628

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feat: hpa with cpu + mem util scaling options #628

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2 changes: 1 addition & 1 deletion charts/telegraf/Chart.yaml
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Original file line number Diff line number Diff line change
@@ -1,6 +1,6 @@
apiVersion: v2
name: telegraf
version: 1.8.42
version: 1.8.43
appVersion: 1.29.5
deprecated: false
description: Telegraf is an agent written in Go for collecting, processing, aggregating, and writing metrics.
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2 changes: 2 additions & 0 deletions charts/telegraf/templates/deployment.yaml
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Expand Up @@ -5,7 +5,9 @@ metadata:
labels:
{{- include "telegraf.labels" . | nindent 4 }}
spec:
{{- if not .Values.autoscaling.enabled}}
replicas: {{ .Values.replicaCount }}
{{- end }}
selector:
matchLabels:
app.kubernetes.io/name: {{ include "telegraf.name" . }}
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36 changes: 36 additions & 0 deletions charts/telegraf/templates/horizontalpodautoscaler.yaml
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Original file line number Diff line number Diff line change
@@ -0,0 +1,36 @@
{{- if .Values.autoscaling.enabled }}
apiVersion: autoscaling/v2
kind: HorizontalPodAutoscaler
metadata:
name: {{ include "telegraf.fullname" . }}
labels:
{{- include "telegraf.labels" . | nindent 4 }}
spec:
scaleTargetRef:
apiVersion: apps/v1
kind: Deployment
name: {{ include "telegraf.fullname" . }}
minReplicas: {{ .Values.autoscaling.minReplicas }}
maxReplicas: {{ .Values.autoscaling.maxReplicas }}
{{- if .Values.autoscaling.behavior }}
behavior:
{{- toYaml .Values.autoscaling.behavior | nindent 4 }}
{{- end }}
metrics:
{{- if .Values.autoscaling.targetMemoryUtilizationPercentage }}
- type: Resource
resource:
name: memory
target:
type: Utilization
averageUtilization: {{ .Values.autoscaling.targetMemoryUtilizationPercentage }}
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ok so I understand that the autoscaler will launch additional telegraf nodes if you get above a certain memory and CPU usage, but what ensures that the first pod gets reduced usage? Is there a load balancer or some other proxy in front that would round robin the usage?

Trying to understand the full use-case and how a user would take advantage of this without needing to make modifications to their config. Thanks!

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@burnjake burnjake Apr 5, 2024 •
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Hi! Apologies I've been away for a few days. So our use case is to utilise the opentelemetry input, aggregate with basicstats and output with the prometheusclient. We have a traffic pattern where the number of connections varies quite a lot within the day, so varying our replica count is prudent.

As the opentelemetry input expects connections via gRPC, we can't depend on normal load balancing via a k8s service and instead we need to use rely on an external LB which we've plumbed into the ingress of the cluster which will discover the new replicas and do the things to spread the traffic (update its connection pool I think?). In short, we don't need extra configuration within telegraf for this to work, but our use case is indeed very specific!

{{- end }}
{{- if .Values.autoscaling.targetCPUUtilizationPercentage }}
- type: Resource
resource:
name: cpu
target:
type: Utilization
averageUtilization: {{ .Values.autoscaling.targetCPUUtilizationPercentage }}
{{- end }}
{{- end }}
8 changes: 8 additions & 0 deletions charts/telegraf/values.yaml
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Original file line number Diff line number Diff line change
Expand Up @@ -180,3 +180,11 @@ pdb:
create: true
minAvailable: 1
# maxUnavailable: 1

autoscaling:
enabled: false
minReplicas: 1
maxReplicas: 5
targetCPUUtilizationPercentage: 80
targetMemoryUtilizationPercentage: 80
behavior: {}