blog: Add anti-affinity to deployment

apps/okd4/shivering-isles/blog/deploymentconfig.yaml

@@ -23,6 +23,16 @@ spec:
         app: blog
         deploymentconfig: blog
     spec:
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+          - labelSelector:
+              matchExpressions:
+              - key: app
+                operator: In
+                values:
+                - blog
+            topologyKey: "kubernetes.io/hostname"
       containers:
       - name: blog
         image: image-registry.openshift-image-registry.svc:5000/blog/blog:latest