Make random scheduler filter nodes by nodeSelector

execution/infrastructure/random-scheduler/schedule.sh

 #!/bin/bash
 
 # use kubectl in proxy mode in order to allow curl requesting the k8's api server
-kubectl proxy --port 8080 &
+#kubectl proxy --port 8080 &
 
 echo "Target Namespace: $TARGET_NAMESPACE"
 while true;
 do
     for PODNAME in $(kubectl get pods -n $TARGET_NAMESPACE -o json | jq '.items[] | select(.spec.schedulerName == "random-scheduler") | select(.spec.nodeName == null) | .metadata.name' | tr -d '"');
     do
-        NODES=($(kubectl get nodes -o json | jq '.items[].metadata.name' | tr -d '"'))
+        NODE_SELECTOR=$(kubectl get pod $PODNAME -n $TARGET_NAMESPACE -o json | jq -S 'if .spec.nodeSelector != null then .spec.nodeSelector else {} end')
+        NODES=($(kubectl get nodes -o json | jq --argjson nodeSelector "$NODE_SELECTOR" '.items[] | select(.metadata.labels | contains($nodeSelector)) | .metadata.name' | tr -d '"'))
         NUMNODES=${#NODES[@]}
+        if [ $NUMNODES -eq 0 ]; then
+            echo "No nodes found matching the node selector: $NODE_SELECTOR from pod $PODNAME"
+            echo "Pod $PODNAME cannot be scheduled."
+            continue;
+        fi
+        echo "Found $NODES suitable nodes for pod $PODNAME"
         CHOSEN=${NODES[$[$RANDOM % $NUMNODES]]}
         curl --header "Content-Type:application/json" --request POST --data '{"apiVersion":"v1", "kind": "Binding", "metadata": {"name": "'$PODNAME'"}, "target": {"apiVersion": "v1", "kind": "Node", "name": "'$CHOSEN'"}}' localhost:8080/api/v1/namespaces/$TARGET_NAMESPACE/pods/$PODNAME/binding/
         echo "Assigned $PODNAME to $CHOSEN"