feat(common): force recreate on single-replica with RWO storage (#33990)

**Description**
This should ensure users cannot set "rolling update" when using RWO
storage and a single-replica, as this would inherently brick pod
updates, as storage would, inherently, stay locked with the previous pod
instance

⚒️ Fixes  #33097

**⚙️ Type of change**

- [ ] ⚙️ Feature/App addition
- [x] 🪛 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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**📃 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`

---

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---------

Signed-off-by: Alfred Göppel <43101280+alfi0812@users.noreply.github.com>
Co-authored-by: Stavros Kois <s.kois@outlook.com>
Co-authored-by: Alfred Göppel <43101280+alfi0812@users.noreply.github.com>

charts/library/common-test/Chart.yaml

@@ -35,4 +35,3 @@ sources:
   - https://github.com/truecharts/charts/tree/master/charts/library/common-test
 type: application
 version: 1.0.0
-

charts/library/common-test/tests/persistence/pvc_stategy_type_test.yaml

@@ -0,0 +1,153 @@
+suite: pvc strategy type test
+templates:
+  - common.yaml
+release:
+  name: test-release-name
+  namespace: test-release-namespace
+tests:
+  - it: should leave strategy as defined with non RWO accessModes and single replica
+    set:
+      workload:
+        some-workload:
+          enabled: true
+          primary: true
+          type: Deployment
+          strategy: RollingUpdate
+          podSpec: {}
+      persistence:
+        my-volume1:
+          enabled: true
+          type: pvc
+          accessModes:
+            - ReadWriteMany
+    asserts:
+      - documentIndex: &deploymentDoc 0
+        isKind:
+          of: Deployment
+      - documentIndex: *deploymentDoc
+        equal:
+          path: spec.strategy.type
+          value: RollingUpdate
+      - documentIndex: &pvcDoc 1
+        isKind:
+          of: PersistentVolumeClaim
+      - documentIndex: *pvcDoc
+        equal:
+          path: metadata.name
+          value: test-release-name-common-test-my-volume1
+      - documentIndex: *pvcDoc
+        equal:
+          path: spec.accessModes
+          value:
+            - ReadWriteMany
+  - it: should set strategy to Recreate with RWO accessModes and single replica
+    set:
+      workload:
+        some-workload:
+          enabled: true
+          primary: true
+          type: Deployment
+          strategy: RollingUpdate
+          podSpec: {}
+      persistence:
+        my-volume1:
+          enabled: true
+          type: pvc
+          accessModes:
+            - ReadWriteMany
+            - ReadWriteOnce
+    asserts:
+      - documentIndex: &deploymentDoc 0
+        isKind:
+          of: Deployment
+      - documentIndex: *deploymentDoc
+        equal:
+          path: spec.strategy.type
+          value: Recreate
+      - documentIndex: &pvcDoc 1
+        isKind:
+          of: PersistentVolumeClaim
+      - documentIndex: *pvcDoc
+        equal:
+          path: metadata.name
+          value: test-release-name-common-test-my-volume1
+      - documentIndex: *pvcDoc
+        equal:
+          path: spec.accessModes
+          value:
+            - ReadWriteMany
+            - ReadWriteOnce
+  - it: should leave strategy as defined with non RWO accessModes and multiple replica
+    set:
+      workload:
+        some-workload:
+          enabled: true
+          primary: true
+          type: Deployment
+          replicas: 2
+          strategy: RollingUpdate
+          podSpec: {}
+      persistence:
+        my-volume1:
+          enabled: true
+          type: pvc
+          accessModes:
+            - ReadWriteMany
+    asserts:
+      - documentIndex: &deploymentDoc 0
+        isKind:
+          of: Deployment
+      - documentIndex: *deploymentDoc
+        equal:
+          path: spec.strategy.type
+          value: RollingUpdate
+      - documentIndex: &pvcDoc 1
+        isKind:
+          of: PersistentVolumeClaim
+      - documentIndex: *pvcDoc
+        equal:
+          path: metadata.name
+          value: test-release-name-common-test-my-volume1
+      - documentIndex: *pvcDoc
+        equal:
+          path: spec.accessModes
+          value:
+            - ReadWriteMany
+  - it: should leave strategy as defined with RWO accessModes and multiple replica
+    set:
+      workload:
+        some-workload:
+          enabled: true
+          primary: true
+          type: Deployment
+          replicas: 2
+          strategy: RollingUpdate
+          podSpec: {}
+      persistence:
+        my-volume1:
+          enabled: true
+          type: pvc
+          accessModes:
+            - ReadWriteMany
+            - ReadWriteOnce
+    asserts:
+      - documentIndex: &deploymentDoc 0
+        isKind:
+          of: Deployment
+      - documentIndex: *deploymentDoc
+        equal:
+          path: spec.strategy.type
+          value: RollingUpdate
+      - documentIndex: &pvcDoc 1
+        isKind:
+          of: PersistentVolumeClaim
+      - documentIndex: *pvcDoc
+        equal:
+          path: metadata.name
+          value: test-release-name-common-test-my-volume1
+      - documentIndex: *pvcDoc
+        equal:
+          path: spec.accessModes
+          value:
+            - ReadWriteMany
+            - ReadWriteOnce

charts/library/common/templates/lib/pod/_volumes.tpl

@@ -96,15 +96,9 @@ objectData: The object data to be used to render the Pod.
         "objectData" $persistence "caller" "Volumes") | fromYamlArray
     -}}
 
-    {{- $hasRWO := false -}}
-    {{- range $m := $modes -}}
-      {{- if eq $m "ReadWriteOnce" -}}
-        {{- $hasRWO = true -}}
-        {{- break -}}
-      {{- end -}}
-    {{- end -}}
+    {{- $hasRWO := include "tc.v1.common.lib.pod.volumes.hasRWO" (dict "modes" $modes) -}}
 
-    {{- if $hasRWO -}}
+    {{- if eq $hasRWO "true" -}}
       {{- if eq $objectData.type "DaemonSet" -}}
         {{- fail "Expected [accessMode] to not be [ReadWriteOnce] when used on a [DaemonSet]" -}}
 
@@ -117,3 +111,15 @@ objectData: The object data to be used to render the Pod.
 
   {{- end -}}
 {{- end -}}
+
+{{- define "tc.v1.common.lib.pod.volumes.hasRWO" -}}
+  {{- $modes := .modes -}}
+  {{- $hasRWO := false -}}
+  {{- range $m := $modes -}}
+    {{- if eq $m "ReadWriteOnce" -}}
+      {{- $hasRWO = true -}}
+      {{- break -}}
+    {{- end -}}
+  {{- end -}}
+  {{- $hasRWO -}}
+{{- end -}}

charts/library/common/templates/lib/workload/_daemonsetSpec.tpl

@@ -9,10 +9,13 @@ objectData:
 {{- define "tc.v1.common.lib.workload.daemonsetSpec" -}}
   {{- $objectData := .objectData -}}
   {{- $rootCtx := .rootCtx -}}
-  {{- $strategy := $objectData.strategy | default "RollingUpdate" }}
+  {{- include "tc.v1.common.lib.workload.components.strategyType" (dict
+    "rootCtx" $rootCtx "objectData" $objectData
+    "defaultStrategy" "RollingUpdate" "resource" "DaemonSet"
+  ) }}
 revisionHistoryLimit: {{ $objectData.revisionHistoryLimit | default 3 }}
 updateStrategy:
-  type: {{ $strategy }}
+  type: {{ $objectData.strategy }}
   {{- if and (eq $objectData.strategy "RollingUpdate") $objectData.rollingUpdate -}}
     {{ if (or (hasKey $objectData.rollingUpdate "maxUnavailable") (hasKey $objectData.rollingUpdate "maxSurge")) }}
   rollingUpdate:

charts/library/common/templates/lib/workload/_deploymentSpec.tpl

@@ -10,7 +10,10 @@ objectData:
 {{- define "tc.v1.common.lib.workload.deploymentSpec" -}}
   {{- $objectData := .objectData -}}
   {{- $rootCtx := .rootCtx -}}
-  {{- $strategy := $objectData.strategy | default "Recreate" -}}
+  {{- include "tc.v1.common.lib.workload.components.strategyType" (dict
+    "rootCtx" $rootCtx "objectData" $objectData
+    "defaultStrategy" "Recreate" "resource" "Deployment"
+  ) -}}
   {{- $replicas := 1 -}}
   {{- if hasKey $objectData "replicas" -}}
     {{- $replicas = $objectData.replicas -}}
@@ -21,7 +24,7 @@ objectData:
 replicas: {{ $replicas }}
 revisionHistoryLimit: {{ $objectData.revisionHistoryLimit | default 3 }}
 strategy:
-  type: {{ $strategy }}
+  type: {{ $objectData.strategy }}
   {{- if and (eq $objectData.strategy "RollingUpdate") $objectData.rollingUpdate -}}
     {{ if (or (hasKey $objectData.rollingUpdate "maxUnavailable") (hasKey $objectData.rollingUpdate "maxSurge")) }}
   rollingUpdate:

charts/library/common/templates/lib/workload/_statefulsetSpec.tpl

@@ -10,7 +10,10 @@ objectData:
 {{- define "tc.v1.common.lib.workload.statefulsetSpec" -}}
   {{- $objectData := .objectData -}}
   {{- $rootCtx := .rootCtx -}}
-  {{- $strategy := $objectData.strategy | default "RollingUpdate" -}}
+  {{- include "tc.v1.common.lib.workload.components.strategyType" (dict
+    "rootCtx" $rootCtx "objectData" $objectData
+    "defaultStrategy" "RollingUpdate" "resource" "StatefulSet"
+  ) -}}
   {{- $replicas := 1 -}}
   {{- if hasKey $objectData "replicas" -}}
     {{- $replicas = $objectData.replicas -}}
@@ -22,7 +25,7 @@ replicas: {{ $replicas }}
 revisionHistoryLimit: {{ $objectData.revisionHistoryLimit | default 3 }}
 serviceName: {{ $objectData.name }}
 updateStrategy:
-  type: {{ $strategy }}
+  type: {{ $objectData.strategy }}
   {{- if and (eq $objectData.strategy "RollingUpdate") $objectData.rollingUpdate -}}
     {{- if (or (hasKey $objectData.rollingUpdate "maxUnavailable") (hasKey $objectData.rollingUpdate "partition")) }}
   rollingUpdate:

charts/library/common/templates/lib/workload/components/_strategyType.tpl

@@ -0,0 +1,71 @@
+{{/* Call this template:
+{{ include "tc.v1.common.lib.workload.components.strategyType" (dict "rootCtx" $rootCtx "objectData" $objectData) -}}
+rootCtx: The root context of the chart.
+objectData:
+  replicas: The number of replicas.
+  strategy: The deployment strategy to use to replace existing pods with new ones.
+*/}}
+{{- define "tc.v1.common.lib.workload.components.strategyType" -}}
+  {{- $objectData := .objectData -}}
+  {{- $rootCtx := .rootCtx -}}
+  {{- $defaultStrategy := .defaultStrategy -}}
+  {{- $resource := .resource -}}
+  {{- $strategy := $objectData.strategy | default $defaultStrategy -}}
+
+  {{- $replicas := 1 -}}
+  {{- if hasKey $objectData "replicas" -}}
+    {{- $replicas = $objectData.replicas -}}
+  {{- end -}}
+  {{- $replicas = $replicas | int -}}
+
+  {{- $volsRWO := list -}}
+  {{- range $name, $persistence := $rootCtx.Values.persistence }}
+    {{- $enabled := (include "tc.v1.common.lib.util.enabled" (dict
+                "rootCtx" $rootCtx "objectData" $persistence
+                "name" $name "caller" "Volumes"
+                "key" "persistence")) -}}
+
+    {{- if (ne $enabled "true") -}}{{- continue -}}{{- end -}}
+
+    {{- $type := ($persistence.type | default $rootCtx.Values.global.fallbackDefaults.persistenceType) -}}
+    {{- $typesWithAccessMode := (list "pvc") -}}
+
+    {{- if (mustHas $type $typesWithAccessMode) -}}
+      {{- $modes := include "tc.v1.common.lib.pvc.accessModes" (dict "rootCtx" $rootCtx
+          "objectData" $persistence "caller" "Volumes") | fromYamlArray
+      -}}
+
+      {{- $hasRWO := include "tc.v1.common.lib.pod.volumes.hasRWO" (dict "modes" $modes) -}}
+      {{- if ne $hasRWO "true" -}}{{- continue -}}{{- end -}}
+      {{- $volsRWO = mustAppend $volsRWO $name -}}
+    {{- end -}}
+  {{- end -}}
+
+  {{/* If there are any RWO vols, do some checks and add warnings */}}
+  {{- if gt (len $volsRWO) 0 -}}
+    {{/* RWO + replicas > 1 is a no-no */}}
+    {{- if gt $replicas 1 -}}
+      {{- include "add.warning" (dict "rootCtx" $rootCtx "warn" (printf
+          "WARNING: The [accessModes] on volume(s) [%s] is set to [ReadWriteOnce] with a more than 1 replica. This is not stables" (join "," $volsRWO)
+        )) -}}
+    {{- else -}}
+      {{/* DaemonSets and StatefulSets can have RWO with 1 replica under their supported strategies (OnDelete, RollingUpdate) */}}
+
+      {{- if eq $resource "Deployment" -}}
+
+        {{/* On Deployments with single replicas, warn if strategy is not recreate */}}
+        {{- if eq $strategy "Recreate" -}}
+          {{- include "add.warning" (dict "rootCtx" $rootCtx "warn" (printf
+            "WARNING: The [accessModes] on volume(s) [%s] is set to [ReadWriteOnce] with a single replica and an strategy of [%s]. %s"
+            (join "," $volsRWO) $strategy "This is not stable, defaulting to [Recreate] strategy"
+          )) -}}
+        {{- end -}}
+        {{- $strategy = "Recreate" -}}
+
+      {{- end -}}
+    {{- end -}}
+  {{- end -}}
+
+  {{/* Update strategy */}}
+  {{- $_ := set $objectData "strategy" $strategy -}}
+{{- end -}}