Elastic Compute Service:Call API operations over the internal network

ECS provides public endpoints. If an ECS instance does not have public bandwidth or a public IP address, you cannot call API operations using tools such as the Alibaba Cloud command-line interface (CLI) or software development kits (SDKs). In this case, you can use one of the following two methods to call API operations over the Alibaba Cloud internal network:

• SDK: The SDK for Java core library V4.5.3 and later supports calling API operations over the internal network in a VPC.

• CLI: When you use the CLI, change the endpoint to the one for the corresponding region to call API operations over the internal network.

Note:

• These two methods are region-specific. You can use an endpoint to manage resources only in the same region as the ECS instance. Cross-region operations are not supported.

• To create ECS instances, use a custom image on which the Alibaba Cloud CLI or an SDK is already deployed. This prevents the instances from failing to load dependencies because they do not have Internet access.

The following table lists the ECS endpoints that support API calls over the internal network. Ensure that the endpoint you use is listed in this table.

When you use an SDK, you can call API operations over the internal network using a simple configuration. The following Java code is an example:

import com.aliyun.ecs20140526.Client;
import com.aliyun.ecs20140526.models.DescribeRegionsRequest;
import com.aliyun.ecs20140526.models.DescribeRegionsResponse;
import com.aliyun.teaopenapi.models.Config;
import com.aliyun.teautil.models.RuntimeOptions;

public class Test {
    public static void main(String[] args) throws Exception {
        Config config = new Config();
        // Required. Make sure that the ALIBABA_CLOUD_ACCESS_KEY_ID environment variable is set.
        config.setAccessKeyId(System.getenv("ALIBABA_CLOUD_ACCESS_KEY_ID"));
        // Required. Make sure that the ALIBABA_CLOUD_ACCESS_KEY_SECRET environment variable is set.
        config.setAccessKeySecret(System.getenv("ALIBABA_CLOUD_ACCESS_KEY_SECRET"));
        // For the endpoint, see https://api.aliyun.com/product/Ecs
        config.setEndpoint("<ENDPOINT>");
        // Initialize the ECS client.
        Client ecsClient = new Client(config);
        // Create a request object to query region information.
        DescribeRegionsRequest describeRegionsRequest = new DescribeRegionsRequest();
        // Create a runtime options object.
        RuntimeOptions runtime = new RuntimeOptions();
        // Send the request and obtain the response with region information.
        DescribeRegionsResponse response = ecsClient.describeRegionsWithOptions(describeRegionsRequest, runtime);
        System.out.println(response.body.toMap());
    }
}

This example uses the DescribeRegions operation. The sample command is as follows:

aliyun ecs DescribeRegions --endpoint ecs-vpc.cn-hangzhou.aliyuncs.com