diff --git a/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sIpamHandler.java b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sIpamHandler.java
index fefb952..e7d0c45 100644
--- a/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sIpamHandler.java
+++ b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sIpamHandler.java
@@ -43,7 +43,6 @@
 import java.util.Set;
 import java.util.concurrent.ExecutorService;
 
-import static java.lang.Thread.sleep;
 import static java.util.concurrent.Executors.newSingleThreadExecutor;
 import static org.onlab.util.Tools.groupedThreads;
 import static org.onosproject.k8snetworking.api.Constants.K8S_NETWORKING_APP_ID;
@@ -61,8 +60,6 @@
     private static final String IP_ADDRESS = "ipAddress";
     private static final String NETWORK_ID = "networkId";
 
-    private static final int RETRY_NUM = 5;
-    private static final int RETRY_DELAY_MS = 3000;
 
     @Reference(cardinality = ReferenceCardinality.MANDATORY)
     protected CoreService coreService;
@@ -142,7 +139,25 @@
             }
 
             Set<IpAddress> ips = getSubnetIps(event.subject().cidr());
-            k8sIpamAdminService.initializeIpPool(event.subject().networkId(), ips);
+            String networkId = event.subject().networkId();
+            k8sIpamAdminService.initializeIpPool(networkId, ips);
+
+            k8sPodService.pods().stream()
+                    .filter(p -> p.getStatus().getPodIP() != null)
+                    .filter(p -> p.getMetadata().getAnnotations() != null)
+                    .filter(p -> networkId.equals(p.getMetadata()
+                                 .getAnnotations().get(NETWORK_ID)))
+                    .forEach(p -> {
+                        String podIp = p.getStatus().getPodIP();
+
+                        // if the POD with valid IP address has not yet been
+                        // added into IPAM IP pool, we will reserve that IP address
+                        // for the POD
+                        if (!k8sIpamAdminService.allocatedIps(networkId)
+                                .contains(IpAddress.valueOf(podIp))) {
+                            k8sIpamAdminService.reserveIp(networkId, IpAddress.valueOf(podIp));
+                        }
+                    });
         }
 
         private void processNetworkRemoval(K8sNetworkEvent event) {
@@ -201,15 +216,11 @@
 
             k8sIpamAdminService.availableIps(annotNetwork);
 
-            int cnt = 0;
-            while ((RETRY_NUM - cnt > 0) && !containIp(annotIp, annotNetwork)) {
-                try {
-                    sleep(RETRY_DELAY_MS);
-                } catch (InterruptedException e) {
-                    log.error("Exception caused during checking available IP addresses");
-                }
-
-                cnt++;
+            // if the kubernetes network has been initialized, we may have
+            // empty available IP pool, in this case, we will postpone IP reserve
+            // process until finishing kubernetes network initialization
+            if (!containIp(annotIp, annotNetwork)) {
+                return;
             }
 
             k8sIpamAdminService.reserveIp(annotNetwork, IpAddress.valueOf(podIp));
diff --git a/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sServiceHandler.java b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sServiceHandler.java
index 2640508..18b9a11 100644
--- a/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sServiceHandler.java
+++ b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/impl/K8sServiceHandler.java
@@ -398,6 +398,10 @@
                                 }
                             }
 
+                            if (targetPortInt == 0) {
+                                continue;
+                            }
+
                             for (EndpointPort endpointPort : endpointSubset.getPorts()) {
                                 if (targetProtocol.equals(endpointPort.getProtocol()) &&
                                         (targetPortInt.equals(endpointPort.getPort()) ||
@@ -426,12 +430,17 @@
                 List<GroupBucket> bkts = Lists.newArrayList();
 
                 for (String ip : epas) {
+                    GroupBucket bkt = buildBuckets(node.intgBridge(),
+                            nodeIpGatewayIpMap.getOrDefault(ip, ip), sp);
+
+                    if (bkt == null) {
+                        continue;
+                    }
+
                     if (install) {
-                        bkts.add(buildBuckets(node.intgBridge(),
-                                nodeIpGatewayIpMap.getOrDefault(ip, ip), sp));
+                        bkts.add(bkt);
                     } else {
-                        bkts.add(buildBuckets(node.intgBridge(),
-                                nodeIpGatewayIpMap.getOrDefault(ip, ip), sp));
+                        bkts.remove(bkt);
                     }
                 }
 
@@ -462,10 +471,12 @@
                             targetPort = sp.getTargetPort().getIntVal();
                         }
 
-                        setUnshiftDomainRules(node.intgBridge(), POD_TABLE,
-                                PRIORITY_NAT_RULE, serviceIp, sp.getPort(),
-                                sp.getProtocol(), podIp,
-                                targetPort, install);
+                        if (targetPort != 0) {
+                            setUnshiftDomainRules(node.intgBridge(), POD_TABLE,
+                                    PRIORITY_NAT_RULE, serviceIp, sp.getPort(),
+                                    sp.getProtocol(), podIp,
+                                    targetPort, install);
+                        }
                     })
             );
         }
@@ -483,6 +494,10 @@
             targetPort = sp.getTargetPort().getIntVal();
         }
 
+        if (targetPort == 0) {
+            return null;
+        }
+
         if (TCP.equals(sp.getProtocol())) {
             tBuilder.setTcpDst(TpPort.tpPort(targetPort));
         } else if (UDP.equals(sp.getProtocol())) {
@@ -493,6 +508,7 @@
                 deviceService.getDevice(deviceId), ACL_TABLE);
         tBuilder.extension(resubmitTreatment, deviceId);
 
+        // TODO: need to adjust group bucket weight by considering POD locality
         return buildGroupBucket(tBuilder.build(), SELECT, (short) -1);
     }
 
diff --git a/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/util/K8sNetworkingUtil.java b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/util/K8sNetworkingUtil.java
index 045b300..7d20b65 100644
--- a/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/util/K8sNetworkingUtil.java
+++ b/apps/k8s-networking/app/src/main/java/org/onosproject/k8snetworking/util/K8sNetworkingUtil.java
@@ -492,6 +492,11 @@
      *         return 0 if there is no port number mapped with the given port name
      */
     public static int portNumberByName(Pod pod, String portName) {
+
+        if (pod == null || pod.getSpec() == null) {
+            return 0;
+        }
+
         for (Container container : pod.getSpec().getContainers()) {
             for (ContainerPort cp : container.getPorts()) {
                 if (cp.getName() != null && cp.getName().equals(portName)) {