feat(common): add support for Vertical Pod Autoscaler (#34502)

**Description**
vertical pod autoscaler would allow our users, even on single nodes, to
more dynamically adapt the resource limits and request of their charts.

For multi-node this will likely also lead to better resource spread.

⚒️ Fixes  #34180

**⚙️ Type of change**

- [x] ⚙️ Feature/App addition
- [ ] 🪛 Bugfix
- [ ] ⚠️ Breaking change (fix or feature that would cause existing
functionality to not work as expected)
- [ ] 🔃 Refactor of current code
- [ ] 📜 Documentation Changes

**🧪 How Has This Been Tested?**
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Please describe the tests that you ran to verify your changes. Provide
instructions so we can reproduce. Please also list any relevant details
for your test configuration
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**📃 Notes:**
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**✔️ Checklist:**

- [ ] ⚖️ My code follows the style guidelines of this project
- [ ] 👀 I have performed a self-review of my own code
- [ ] #️⃣ I have commented my code, particularly in hard-to-understand
areas
- [ ] 📄 I have made changes to the documentation
- [ ] 🧪 I have added tests to this description that prove my fix is
effective or that my feature works
- [ ] ⬆️ I increased versions for any altered app according to semantic
versioning
- [ ] I made sure the title starts with `feat(chart-name):`,
`fix(chart-name):`, `chore(chart-name):`, `docs(chart-name):` or
`fix(docs):`

**➕ App addition**

If this PR is an app addition please make sure you have done the
following.

- [ ] 🖼️ I have added an icon in the Chart's root directory called
`icon.png`

---

_Please don't blindly check all the boxes. Read them and only check
those that apply.
Those checkboxes are there for the reviewer to see what is this all
about and
the status of this PR with a quick glance._

---------

Signed-off-by: Kjeld Schouten <info@kjeldschouten.nl>
Co-authored-by: Stavros Kois <s.kois@outlook.com>

charts/library/common-test/tests/vpa/names_test.yaml

@@ -0,0 +1,63 @@
+suite: vpa name test
+templates:
+  - common.yaml
+release:
+  name: test-release-name
+  namespace: test-release-namespace
+tests:
+  - it: should generate correct vpa name
+    set:
+      workload:
+        workload-name:
+          enabled: true
+          primary: true
+          type: Deployment
+          podSpec: {}
+        workload-name-2:
+          enabled: true
+          type: Deployment
+          podSpec: {}
+      vpa:
+        vpa-name:
+          enabled: true
+    asserts:
+      - documentIndex: &deploymentDoc 0
+        isKind:
+          of: Deployment
+      - documentIndex: *deploymentDoc
+        isAPIVersion:
+          of: apps/v1
+      - documentIndex: *deploymentDoc
+        equal:
+          path: metadata.name
+          value: test-release-name-common-test
+      - documentIndex: &deploymentDoc 1
+        isKind:
+          of: Deployment
+      - documentIndex: *deploymentDoc
+        isAPIVersion:
+          of: apps/v1
+      - documentIndex: *deploymentDoc
+        equal:
+          path: metadata.name
+          value: test-release-name-common-test-workload-name-2
+      - documentIndex: &vpaDoc 2
+        isKind:
+          of: VerticalPodAutoscaler
+      - documentIndex: *vpaDoc
+        isAPIVersion:
+          of: autoscaling.k8s.io/v1
+      - documentIndex: *vpaDoc
+        equal:
+          path: metadata.name
+          value: test-release-name-common-test
+      - documentIndex: &otherVPADoc 3
+        isKind:
+          of: VerticalPodAutoscaler
+      - documentIndex: *otherVPADoc
+        isAPIVersion:
+          of: autoscaling.k8s.io/v1
+      - documentIndex: *otherVPADoc
+        equal:
+          path: metadata.name
+          value: test-release-name-common-test-workload-name-2

charts/library/common-test/tests/vpa/validation_test.yaml

@@ -0,0 +1,156 @@
+suite: vpa validation test
+templates:
+  - common.yaml
+release:
+  name: test-release-name
+  namespace: test-release-namespace
+tests:
+  - it: should fail with name longer than 63 characters
+    set:
+      workload: &workload
+        workload-name:
+          enabled: true
+          primary: true
+          type: Deployment
+          podSpec: {}
+      vpa:
+        ? other-vertical-pod-autoscale-name-super-long-name-that-is-longer-than-63-characters
+        : enabled: true
+    asserts:
+      - failedTemplate:
+          errorMessage: Name [other-vertical-pod-autoscale-name-super-long-name-that-is-longer-than-63-characters] is not valid. Must start and end with an alphanumeric lowercase character. It can contain '-'. And must be at most 63 characters.
+
+  - it: should fail with name starting with underscore
+    set:
+      workload: *workload
+      vpa:
+        _other-vpa-name:
+          enabled: true
+    asserts:
+      - failedTemplate:
+          errorMessage: Name [_other-vpa-name] is not valid. Must start and end with an alphanumeric lowercase character. It can contain '-'. And must be at most 63 characters.
+
+  - it: should fail with labels not a dict
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          labels: "not a dict"
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Expected [labels] to be a dictionary, but got [string]
+
+  - it: should fail with annotations not a dict
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          annotations: "not a dict"
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Expected [annotations] to be a dictionary, but got [string]
+
+  - it: should fail with updatePolicy not a dict
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          updatePolicy: "not a dict"
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Expected [updatePolicy] to be a dictionary, but got [string]
+
+  - it: should fail with updatePolicy.updateMode not valid
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          updatePolicy:
+            updateMode: invalid
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Value [invalid] on [vpa.vpa-name.updatePolicy.updateMode] is not valid. Must be one of [Auto, Off, Initial, Recreate]
+
+  - it: should fail with updatePolicy.minReplicas not a number
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          updatePolicy:
+            minReplicas: "some-number"
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Value [some-number] on [vpa.vpa-name.updatePolicy.minReplicas] must be greater than 0.
+
+  - it: should fail with updatePolicy.minReplicas not a positive number
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          updatePolicy:
+            minReplicas: -1
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Value [-1] on [vpa.vpa-name.updatePolicy.minReplicas] must be greater than 0.
+
+  - it: should fail with evictionRequirements not a list
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          updatePolicy:
+            evictionRequirements: "not a list"
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Value on [vpa.vpa-name.updatePolicy.evictionRequirements] must be a list, but got [string]
+
+  - it: should fail with evictionRequirements.resources not a list
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          updatePolicy:
+            evictionRequirements:
+              - resources: "not a list"
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Value on [vpa.vpa-name.updatePolicy.evictionRequirements.0.resources] must be a list, but got [string]
+
+  - it: should fail with evictionRequirements.resources.0 not a valid resource
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          updatePolicy:
+            evictionRequirements:
+              - resources:
+                  - cpu
+                  - memory
+                  - some-resource
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Value [some-resource] on [vpa.vpa-name.updatePolicy.evictionRequirements.0.resources.2] is not valid. Must be one of [cpu, memory]
+
+  - it: should fail with evictionRequirements.changeRequirement not a valid change requirement
+    set:
+      workload: *workload
+      vpa:
+        vpa-name:
+          enabled: true
+          updatePolicy:
+            evictionRequirements:
+              - resources:
+                  - cpu
+                changeRequirement: some-change-requirement
+    asserts:
+      - failedTemplate:
+          errorMessage: Vertical Pod Autoscaler - Value [some-change-requirement] on [vpa.vpa-name.updatePolicy.evictionRequirements.0.changeRequirement] is not valid. Must be one of [TargetHigherThanRequests, TargetLowerThanRequests]

charts/library/common/Chart.yaml

@@ -48,4 +48,4 @@ sources:
   - https://hub.docker.com/_/
   - https://hub.docker.com/r/mikefarah/yq
 type: library
-version: 28.4.0
+version: 28.5.0

charts/library/common/templates/class/_verticalPodAutoscaler.tpl

@@ -0,0 +1,45 @@
+{{/*
+This template serves as a blueprint for vertical pod autoscaler objects that are created
+using the common library.
+*/}}
+{{- define "tc.v1.common.class.vpa" -}}
+  {{- $rootCtx := .rootCtx -}}
+  {{- $objectData := .objectData -}}
+
+  {{- $_ := set $objectData "updatePolicy" ($objectData.updatePolicy | default dict) -}}
+  {{- $_ := set $objectData "resourcePolicy" ($objectData.resourcePolicy | default dict) }}
+---
+apiVersion: autoscaling.k8s.io/v1
+kind: VerticalPodAutoscaler
+metadata:
+  name: {{ $objectData.name }}
+  namespace: {{ include "tc.v1.common.lib.metadata.namespace" (dict "rootCtx" $rootCtx "objectData" $objectData "caller" "VPA") }}
+  {{- $labels := (mustMerge ($objectData.labels | default dict) (include "tc.v1.common.lib.metadata.allLabels" $rootCtx | fromYaml)) -}}
+  {{- with (include "tc.v1.common.lib.metadata.render" (dict "rootCtx" $rootCtx "labels" $labels) | trim) }}
+  labels:
+    {{- . | nindent 4 }}
+  {{- end -}}
+  {{- $annotations := (mustMerge ($objectData.annotations | default dict) (include "tc.v1.common.lib.metadata.allAnnotations" $rootCtx | fromYaml)) -}}
+  {{- with (include "tc.v1.common.lib.metadata.render" (dict "rootCtx" $rootCtx "annotations" $annotations) | trim) }}
+  annotations:
+    {{- . | nindent 4 }}
+  {{- end }}
+spec:
+  targetRef:
+    apiVersion: apps/v1
+    kind: {{ $objectData.workload.type }}
+    name: {{ $objectData.name }}
+  updatePolicy:
+    updateMode: {{ $objectData.updatePolicy.updateMode | default "Auto" }}
+    {{- with $objectData.updatePolicy.minReplicas }}
+    minReplicas: {{ . }}
+    {{- end -}}
+    {{- if $objectData.updatePolicy.evictionRequirements }}
+    evictionRequirements:
+      {{- range $req := $objectData.updatePolicy.evictionRequirements }}
+      - resources: {{ $req.resources | toJson }}
+        changeRequirement: {{ $req.changeRequirement }}
+      {{- end }}
+    {{- end -}}
+
+{{- end -}}

charts/library/common/templates/lib/vpa/_validation.tpl

@@ -0,0 +1,55 @@
+{{- define "tc.v1.common.lib.vpa.validation" -}}
+  {{- $objectData := .objectData -}}
+  {{- $rootCtx := .rootCtx -}}
+
+  {{- $updPolicy := $objectData.updatePolicy -}}
+  {{- if $updPolicy -}}
+    {{- if not (kindIs "map" $updPolicy) -}}
+      {{- fail (printf "Vertical Pod Autoscaler - Expected [updatePolicy] to be a dictionary, but got [%s]" (kindOf $updPolicy)) -}}
+    {{- end -}}
+
+    {{- if $updPolicy.updateMode -}}
+      {{- $validModes := list "Auto" "Off" "Initial" "Recreate" -}}
+      {{- if not (mustHas $updPolicy.updateMode $validModes) -}}
+        {{- fail (printf "Vertical Pod Autoscaler - Value [%s] on [vpa.%s.updatePolicy.updateMode] is not valid. Must be one of [%s]" $updPolicy.updateMode $objectData.vpaName (join ", " $validModes)) -}}
+      {{- end -}}
+    {{- end -}}
+
+    {{- if and $updPolicy.minReplicas (le ($updPolicy.minReplicas | int) 0) -}}
+      {{- fail (printf "Vertical Pod Autoscaler - Value [%v] on [vpa.%s.updatePolicy.minReplicas] must be greater than 0." $updPolicy.minReplicas $objectData.vpaName) -}}
+    {{- end -}}
+
+    {{- if $updPolicy.evictionRequirements -}}
+      {{- if not (kindIs "slice" $updPolicy.evictionRequirements) -}}
+        {{- fail (printf "Vertical Pod Autoscaler - Value on [vpa.%s.updatePolicy.evictionRequirements] must be a list, but got [%s]" $objectData.vpaName (kindOf $updPolicy.evictionRequirements)) -}}
+      {{- end -}}
+      {{- range $idx, $req := $updPolicy.evictionRequirements -}}
+        {{- if not (kindIs "map" $req) -}}
+          {{- fail (printf "Vertical Pod Autoscaler - Value on [vpa.%s.updatePolicy.evictionRequirements.%d] must be a map, but got [%s]" $objectData.vpaName $idx (kindOf $req)) -}}
+        {{- end -}}
+
+        {{- if not $req.resources -}}
+          {{- fail (printf "Vertical Pod Autoscaler - Value on [vpa.%s.updatePolicy.evictionRequirements.%d.resources] is required." $objectData.vpaName $idx) -}}
+        {{- end -}}
+
+        {{- if not (kindIs "slice" $req.resources) -}}
+          {{- fail (printf "Vertical Pod Autoscaler - Value on [vpa.%s.updatePolicy.evictionRequirements.%d.resources] must be a list, but got [%s]" $objectData.vpaName $idx (kindOf $req.resources)) -}}
+        {{- end -}}
+
+        {{- $validResources := (list "cpu" "memory") -}}
+        {{- range $x, $r := $req.resources -}}
+          {{- if not (mustHas $r $validResources) -}}
+            {{- fail (printf "Vertical Pod Autoscaler - Value [%s] on [vpa.%s.updatePolicy.evictionRequirements.%d.resources.%d] is not valid. Must be one of [%s]" $r $objectData.vpaName $idx $x (join ", " $validResources)) -}}
+          {{- end -}}
+        {{- end -}}
+
+        {{- $validReq := (list "TargetHigherThanRequests" "TargetLowerThanRequests") -}}
+        {{- if not (mustHas $req.changeRequirement $validReq) -}}
+          {{- fail (printf "Vertical Pod Autoscaler - Value [%s] on [vpa.%s.updatePolicy.evictionRequirements.%d.changeRequirement] is not valid. Must be one of [%s]" $req.changeRequirement $objectData.vpaName $idx (join ", " $validReq)) -}}
+        {{- end -}}
+
+      {{- end -}}
+    {{- end -}}
+
+  {{- end -}}
+{{- end -}}

charts/library/common/templates/loader/_apply.tpl

@@ -73,4 +73,7 @@
   {{/* Render Cert-Manager Certificates(s) */}}
   {{- include "tc.v1.common.spawner.certificate" . | nindent 0 -}}
 
+  {{/* Render Vertical Pod Autoscaler */}}
+  {{ include "tc.v1.common.spawner.vpa" . | nindent 0 -}}
+
 {{- end -}}

charts/library/common/templates/spawner/_verticalPodAutoscaler.tpl

@@ -0,0 +1,59 @@
+{{/* Vertical Pod Autoscaler Spawner */}}
+{{/* Call this template:
+{{ include "tc.v1.common.spawner.vpa" $ -}}
+*/}}
+
+{{- define "tc.v1.common.spawner.vpa" -}}
+  {{- $fullname := include "tc.v1.common.lib.chart.names.fullname" $ -}}
+  {{- range $name, $vpa := .Values.vpa -}}
+    {{- $enabledVPA := (include "tc.v1.common.lib.util.enabled" (dict
+                    "rootCtx" $ "objectData" $vpa
+                    "name" $name "caller" "Vertical Pod Autoscaler"
+                    "key" "vpa")) -}}
+
+    {{- if ne $enabledVPA "true" -}}{{- continue -}}{{- end -}}
+
+    {{- $objectData := (mustDeepCopy $vpa) -}}
+    {{- $_ := set $objectData "vpaName" $name -}}
+    {{- include "tc.v1.common.lib.vpa.validation" (dict "objectData" $objectData "rootCtx" $) -}}
+    {{- include "tc.v1.common.lib.chart.names.validation" (dict "name" $name) -}}
+
+    {{- range $workloadName, $workload := $.Values.workload -}}
+
+      {{- $enabled := (include "tc.v1.common.lib.util.enabled" (dict
+                      "rootCtx" $ "objectData" $workload
+                      "name" $name "caller" "vpa"
+                      "key" "workload")) -}}
+
+      {{- if ne $enabled "true" -}}{{- continue -}}{{- end -}}
+
+      {{/* Create a copy of the workload */}}
+      {{- $_ := set $objectData "workload" (mustDeepCopy $workload) -}}
+
+      {{/* Generate the name of the vpa */}}
+      {{- $objectName := $fullname -}}
+      {{- if not $objectData.workload.primary -}}
+        {{- $objectName = printf "%s-%s" $fullname $workloadName -}}
+      {{- end -}}
+
+      {{/* Perform validations */}}
+      {{- include "tc.v1.common.lib.chart.names.validation" (dict "name" $objectName) -}}
+      {{- include "tc.v1.common.lib.metadata.validation" (dict "objectData" $objectData "caller" "Vertical Pod Autoscaler") -}}
+
+      {{/* Set the name of the workload */}}
+      {{- $_ := set $objectData "name" $objectName -}}
+
+      {{/* Short name is the one that defined on the chart, used on selectors */}}
+      {{- $_ := set $objectData "shortName" $workloadName -}}
+
+      {{- if or (not $objectData.targetSelector) (hasKey $objectData.targetSelector $workloadName) -}}
+        {{/* Call class to create the object */}}
+        {{- $types := (list "Deployment" "StatefulSet" "DaemonSet") -}}
+        {{- if (mustHas $objectData.workload.type $types) -}}
+          {{- include "tc.v1.common.class.vpa" (dict "rootCtx" $ "objectData" $objectData) -}}
+        {{- end -}}
+      {{- end -}}
+
+    {{- end -}}
+  {{- end -}}
+{{- end -}}

charts/library/common/values.yaml

@@ -195,6 +195,24 @@ TZ: UTC
 diagnosticMode:
   enabled: false
 
+# -- Vertical pod autoscaler
+vpa:
+  main:
+    enabled: false
+    targetSelector: []
+    # updatePolicy:
+    #   updateMode: auto
+    resourcePolicy:
+      containerPolicies:
+      - containerName: '*'
+        minAllowed:
+          cpu: 50m
+          memory: 50Mi
+        maxAllowed:
+          cpu: 8000m
+          memory: 20Gi
+        controlledResources: ["cpu", "memory"]
+
 # -- (docs/service/README.md)
 service:
   main: