coredns: readiness- and livenessProbe tweaks

The readinessProbe was delaying the startup of coredns greatly. This
change brings startup times from ~15s to ~2-3s when testing locally. A
reduction of ~80%.

The livenessProbe would also take potentially more than a minute to
be declared unhealthy and restarted which is now tweaked down to about
30 seconds

For more information about the probes, see: https://kubernetes.io/docs/tasks/configure-pod-container/configure-liveness-readiness-startup-probes/#configure-probes

manifests/coredns.yaml

@@ -143,18 +143,20 @@ spec:
             port: 8080
             scheme: HTTP
           initialDelaySeconds: 60
-          timeoutSeconds: 5
+          periodSeconds: 10
+          timeoutSeconds: 1
           successThreshold: 1
-          failureThreshold: 5
+          failureThreshold: 3
         readinessProbe:
           httpGet:
             path: /ready
             port: 8181
             scheme: HTTP
-          initialDelaySeconds: 10
-          timeoutSeconds: 5
+          initialDelaySeconds: 0
+          periodSeconds: 2
+          timeoutSeconds: 1
           successThreshold: 1
-          failureThreshold: 5
+          failureThreshold: 3
       dnsPolicy: Default
       volumes:
         - name: config-volume