✨(helm) add pdbs to deployments

In order to avoid a service interruption during a Kubernetes (k8s)
upgrade, we add a Pod Disruption Budget (PDB) to deployments.

src/helm/impress/templates/backend_deployment.yaml

@@ -138,3 +138,16 @@ spec:
           emptyDir: {}
           {{- end }}
         {{- end }}
+---
+{{ if .Values.backend.pdb.enabled }}
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: {{ $fullName }}
+  namespace: {{ .Release.Namespace | quote }}
+spec:
+  maxUnavailable: 1
+  selector:
+    matchLabels:
+      {{- include "impress.common.selectorLabels" (list . $component) | nindent 6 }}
+{{ end }}

src/helm/impress/templates/frontend_deployment.yaml

@@ -138,3 +138,16 @@ spec:
           emptyDir: {}
           {{- end }}
         {{- end }}
+---
+{{ if .Values.frontend.pdb.enabled }}
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: {{ $fullName }}
+  namespace: {{ .Release.Namespace | quote }}
+spec:
+  maxUnavailable: 1
+  selector:
+    matchLabels:
+      {{- include "impress.common.selectorLabels" (list . $component) | nindent 6 }}
+{{ end }}

src/helm/impress/templates/yprovider_deployment.yaml

@@ -138,3 +138,16 @@ spec:
           emptyDir: {}
           {{- end }}
         {{- end }}
+---
+{{ if .Values.yProvider.pdb.enabled }}
+apiVersion: policy/v1
+kind: PodDisruptionBudget
+metadata:
+  name: {{ $fullName }}
+  namespace: {{ .Release.Namespace | quote }}
+spec:
+  maxUnavailable: 1
+  selector:
+    matchLabels:
+      {{- include "impress.common.selectorLabels" (list . $component) | nindent 6 }}
+{{ end }}