Add hub.lifecycle configuration

Author: consideRatio

jupyterhub/schema.yaml

@@ -1092,6 +1092,19 @@ properties:
         description: |
           A k8s native specification of resources, see [the
           documentation](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.20/#resourcerequirements-v1-core).
+      lifecycle: &lifecycle-spec
+        type: object
+        additionalProperties: false
+        description: |
+          A k8s native specification of lifecycle hooks on the container, see [the
+          documentation](https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.20/#lifecycle-v1-core).
+        properties:
+          postStart:
+            type: object
+            additionalProperties: true
+          preStop:
+            type: object
+            additionalProperties: true
       services:
         type: object
         additionalProperties: true

jupyterhub/templates/hub/deployment.yaml

@@ -179,6 +179,10 @@ spec:
           securityContext:
             {{- $securityContext | toYaml | trimSuffix "\n" | nindent 12 }}
           {{- end }}
+          {{- with .Values.hub.lifecycle }}
+          lifecycle:
+            {{- . | toYaml | trimSuffix "\n" | nindent 12 }}
+          {{- end }}
           env:
             - name: PYTHONUNBUFFERED
               value: "1"

jupyterhub/values.yaml

@@ -88,6 +88,7 @@ hub:
     runAsUser: 1000
     runAsGroup: 1000
     allowPrivilegeEscalation: false
+  lifecycle: {}
   services: {}
   pdb:
     enabled: false

tools/templates/lint-and-validate-values.yaml

@@ -124,6 +124,19 @@ hub:
     requests:
       cpu: 100m
       memory: 512Mi
+  lifecycle: &lifecycle
+    postStart:
+      exec:
+        command:
+          - "/bin/sh"
+          - "-c"
+          - "echo Hello from the postStart handler >> /usr/share/message"
+    preStop:
+      exec:
+        command:
+          - "/bin/sh"
+          - "-c"
+          - "echo Hello from the preStart handler >> /usr/share/message"
   services:
     tests:
       apiToken: mocked-api-token
@@ -336,7 +349,7 @@ singleuser:
   events: true
   extraLabels: {}
   extraEnv: {}
-  lifecycleHooks: {}
+  lifecycleHooks: *lifecycle
   initContainers:
     - name: mock-init-container-name
       image: mock-init-container-image