@Override
        public void onUpdate(final Pod oldObj, final Pod newObj) {
            updateRemoteInstances(newObj, MODIFIED);
        }
Read collector pod info from api-server of kubernetes, then using all containerIp list to construct the list of
{@link RemoteInstance}.
oap-server/server-cluster-plugin/cluster-kubernetes-plugin/src/main/java/org/apache/skywalking/oap/server/cluster/plugin/kubernetes/KubernetesCoordinator.java