Add podaffinity to pack pods into nodes

Author: kalindudc

applications/python-echo-server/deploy/manifest.yaml

@@ -7,7 +7,7 @@ metadata:
   name: python-echo-server
   namespace: python-echo-server
 spec:
-  replicas: 1
+  replicas: 4
   selector:
     matchLabels:
       app: python-echo-server
@@ -16,6 +16,18 @@ spec:
       labels:
         app: python-echo-server
     spec:
+      affinity:
+        podAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+          - weight: 100
+            podAffinityTerm:
+              labelSelector:
+                matchExpressions:
+                - key: app
+                  operator: In
+                  values:
+                  - python-echo-server
+              topologyKey: "kubernetes.io/hostname"
       containers:
       - env:
         - name: PORT

applications/python-echo-server/main.py

@@ -33,6 +33,7 @@ def ping():
   def echo():
     kubernetes_info = [
       "Kubernetes Info: ",
+      "\tHostname: " + os.environ.get("HOSTNAME", "N/A"),
       "\tCluster Name: " + os.environ.get("CLUSTER_NAME", "N/A"),
       "\tNamespace: " + os.environ.get("POD_NAMESPACE", "N/A"),
       "\tNode Name: " + os.environ.get("NODE_NAME", "N/A"),