[stable/coredns] Add ReadinessProbe (#15295)

Signed-off-by: Manuel Rüger <manuel@rueg.eu>

stable/coredns/Chart.yaml

@@ -1,6 +1,6 @@
 apiVersion: v1
 name: coredns
-version: 1.5.5
+version: 1.5.6
 appVersion: 1.5.2
 description: CoreDNS is a DNS server that chains plugins and provides Kubernetes DNS Services
 keywords:

stable/coredns/templates/deployment.yaml

@@ -76,6 +76,15 @@ spec:
           timeoutSeconds: 5
           successThreshold: 1
           failureThreshold: 5
+        readinessProbe:
+          httpGet:
+            path: /ready
+            port: 8181
+            scheme: HTTP
+          initialDelaySeconds: 10
+          timeoutSeconds: 5
+          successThreshold: 1
+          failureThreshold: 5
       volumes:
         - name: config-volume
           configMap:

stable/coredns/values.yaml

@@ -63,6 +63,8 @@ servers:
     parameters: 30
   - name: errors
   - name: health
+  # Serves a /ready endpoint on :8181
+  - name: ready
   - name: kubernetes
     parameters: cluster.local
   - name: loadbalance