Debug toolbox in a sidecar container

charts/onechart/Chart.yaml

@@ -15,4 +15,4 @@ type: application
 # This is the chart version. This version number should be incremented each time you make changes
 # to the chart and its templates, including the app version.
 # Versions are expected to follow Semantic Versioning (https://semver.org/)
-version: 0.11.0
+version: 0.12.0

charts/onechart/templates/deployment.yaml

@@ -28,17 +28,17 @@ spec:
         {{- toYaml .Values.podSecurityContext | nindent 8 }}
       containers:
         - name: {{ .Release.Name }}
-          securityContext:
+          securityContext: &securityContext
             {{- toYaml .Values.securityContext | nindent 12 }}
           image: "{{ .Values.image.repository }}:{{ .Values.image.tag | default .Chart.AppVersion }}"
-          imagePullPolicy: {{ .Values.image.pullPolicy }}
+          imagePullPolicy: {{ .Values.image.pullPolicy }} &imagePullPolicy
           {{- if .Values.command }}
           command:
             - {{ .Values.shell }}
             - -c
             - {{ .Values.command | quote }}
           {{- end }}
-          envFrom:
+          envFrom: &envFrom
             {{- if .Values.vars }}
             - configMapRef:
                 name: {{ .Release.Name }}
@@ -66,7 +66,7 @@ spec:
             successThreshold: 1
             timeoutSeconds: 10
           {{- end }}
-          volumeMounts:
+          volumeMounts: &volumeMounts
             {{- range .Values.volumes }}
             - name: {{ .name }}
               mountPath: {{ .path }}
@@ -78,6 +78,18 @@ spec:
             {{- end }}
           resources:
             {{- toYaml .Values.resources | nindent 12 }}
+        {{- if .Values.debugSidecarEnabled }}
+        - name: {{ .Release.Name }}-debug
+          securityContext: *securityContext
+          image: {{ .Values.debugSidecar.image }}
+          imagePullPolicy: *imagePullPolicy
+          command:
+            - {{ .Values.debugSidecar.shell }}
+            - -c
+            - {{ .Values.debugSidecar.command | quote }}
+          envFrom: *envFrom
+          volumeMounts: *volumeMounts
+        {{- end }}
       volumes:
         {{- range .Values.volumes }}
         - name: {{ .name }}

charts/onechart/tests/deployment_debug_sidecar_test.yaml

@@ -0,0 +1,12 @@
+suite: test deployment
+templates:
+  - deployment.yaml
+  - configmap.yaml
+tests:
+  - it: Should add a debug sidecar
+    set:
+      debugSidecarEnabled: true
+    asserts:
+      - equal:
+          path: spec.template.spec.containers[1].image
+          value: debian:stable-slim

charts/onechart/values.yaml

@@ -38,3 +38,9 @@ secret:
   enabled: false
 
 shell: "/bin/sh"
+
+debugSidecarEnabled: false
+debugSidecar:
+  image: debian:stable-slim
+  shell: "/bin/bash"
+  command: "while true; do sleep 30; done;"