Try with less cpu requests and anti-affinity, #30874 (#30883)

* trying to fix the "does not have a host assigned" for some pods
  after the change to 10 pods
* reducing StressSpec to 10 multi-nodes

akka-cluster/src/multi-jvm/scala/akka/cluster/StressSpec.scala

@@ -62,7 +62,7 @@ private[cluster] object StressMultiJvmSpec extends MultiNodeConfig {
 
   val totalNumberOfNodes =
     System.getProperty("MultiJvm.akka.cluster.Stress.nrOfNodes") match {
-      case null  => 13
+      case null  => 10
       case value => value.toInt.requiring(_ >= 10, "nrOfNodes should be >= 10")
     }
 
@@ -77,13 +77,13 @@ private[cluster] object StressMultiJvmSpec extends MultiNodeConfig {
       nr-of-nodes-factor = 1
       # not scaled
       nr-of-seed-nodes = 3
-      nr-of-nodes-joining-to-seed-initially = 2
-      nr-of-nodes-joining-one-by-one-small = 2
-      nr-of-nodes-joining-one-by-one-large = 2
-      nr-of-nodes-joining-to-one = 2
+      nr-of-nodes-joining-to-seed-initially = 1
+      nr-of-nodes-joining-one-by-one-small = 1
+      nr-of-nodes-joining-one-by-one-large = 1
+      nr-of-nodes-joining-to-one = 1
       nr-of-nodes-leaving-one-by-one-small = 1
       nr-of-nodes-leaving-one-by-one-large = 1
-      nr-of-nodes-leaving = 2
+      nr-of-nodes-leaving = 1
       nr-of-nodes-shutdown-one-by-one-small = 1
       nr-of-nodes-shutdown-one-by-one-large = 1
       nr-of-nodes-partition = 2
@@ -432,9 +432,6 @@ class StressMultiJvmNode7 extends StressSpec
 class StressMultiJvmNode8 extends StressSpec
 class StressMultiJvmNode9 extends StressSpec
 class StressMultiJvmNode10 extends StressSpec
-class StressMultiJvmNode11 extends StressSpec
-class StressMultiJvmNode12 extends StressSpec
-class StressMultiJvmNode13 extends StressSpec
 
 abstract class StressSpec
     extends MultiNodeSpec(StressMultiJvmSpec)

kubernetes/test-node-base.yaml

@@ -14,15 +14,27 @@ spec:
       labels:
         host: test-nodeX
     spec:
+      affinity:
+        podAntiAffinity:
+          preferredDuringSchedulingIgnoredDuringExecution:
+            - weight: 100
+              podAffinityTerm:
+                labelSelector:
+                  matchExpressions:
+                    - key: app
+                      operator: In
+                      values:
+                        - multi-node-test
+                topologyKey: kubernetes.io/hostname
       containers:
       - image: openjdk:11
         command: ["sleep", "infinity"]
         resources:
           requests:
-            memory: "4Gi"
-            cpu: "1800m"
+            memory: "3Gi"
+            cpu: "1400m"
           limits:
-            memory: "4Gi"
+            memory: "3Gi"
         lifecycle:
           postStart:
             exec: