public Observable<AwsState> pollForInstanceState(final String loadBalancer) { try { return Observable.from(elbAsyncClient.describeInstanceHealthAsync(new DescribeInstanceHealthRequest().withLoadBalancerName(loadBalancer).withInstances(new Instance().withInstanceId(instanceId)))) .flatMap(result -> { Optional<InstanceState> state = result.getInstanceStates().stream().filter(i -> i.getInstanceId().equals(instanceId)).findFirst(); return just(state.map(instanceState -> AwsState.map(instanceState.getState())).orElse(AwsState.UNKNOWN)); }); } catch (AmazonClientException e) { LOG.error(LogConstants.ERROR_EXECUTING_REQUEST, e); throw new AwsException(e); } }