AWS角色与密钥

问题描述

AWS角色用于需要访问AWS服务的服务，例如S3等使用临时凭证。这些都是使用STS完成的。当来自一个帐户的用户/应用程序需要临时访问其他帐户拥有的资源时，这很有用。

但是，仅当使用Profile属性传递凭据时，STS才会发布临时凭据。无论如何，至少这就是AWS提供的代码所隐含的含义

import com.amazonaws.AmazonServiceException;
import com.amazonaws.SdkClientException;
import com.amazonaws.auth.AWsstaticCredentialsProvider;
import com.amazonaws.auth.BasicSessionCredentials;
import com.amazonaws.auth.profile.ProfileCredentialsProvider;
import com.amazonaws.services.s3.AmazonS3;
import com.amazonaws.services.s3.AmazonS3ClientBuilder;
import com.amazonaws.services.s3.model.ObjectListing;
import com.amazonaws.services.securitytoken.AWSSecurityTokenService;
import com.amazonaws.services.securitytoken.AWSSecurityTokenServiceClientBuilder;
import com.amazonaws.services.securitytoken.model.AssumeRoleRequest;
import com.amazonaws.services.securitytoken.model.AssumeRoleResult;
import com.amazonaws.services.securitytoken.model.Credentials;

public class MakingRequestsWithIAMTempCredentials {
    public static void main(String[] args) {
        String clientRegion = "*** Client region ***";
        String roleARN = "*** ARN for role to be assumed ***";
        String roleSessionName = "*** Role session name ***";
        String bucketName = "*** Bucket name ***";

        try {
            // Creating the STS client is part of your trusted code. It has
            // the security credentials you use to obtain temporary security credentials.
            AWSSecurityTokenService stsClient = AWSSecurityTokenServiceClientBuilder.standard()
                                                    .withCredentials(new ProfileCredentialsProvider())
                                                    .withRegion(clientRegion)
                                                    .build();

            // Obtain credentials for the IAM role. Note that you cannot assume the role of an AWS root account;
            // Amazon S3 will deny access. You must use credentials for an IAM user or an IAM role.
            AssumeRoleRequest roleRequest = new AssumeRoleRequest()
                                                    .withRoleArn(roleARN)
                                                    .withRoleSessionName(roleSessionName);
            AssumeRoleResult roleResponse = stsClient.assumeRole(roleRequest);
            Credentials sessionCredentials = roleResponse.getCredentials();
            
            // Create a BasicSessionCredentials object that contains the credentials you just retrieved.
            BasicSessionCredentials awsCredentials = new BasicSessionCredentials(
                    sessionCredentials.getAccessKeyId(),sessionCredentials.getSecretAccessKey(),sessionCredentials.getSessionToken());

            // Provide temporary security credentials so that the Amazon S3 client 
        // can send authenticated requests to Amazon S3. You create the client 
        // using the sessionCredentials object.
            AmazonS3 s3Client = AmazonS3ClientBuilder.standard()
                                    .withCredentials(new AWsstaticCredentialsProvider(awsCredentials))
                                    .withRegion(clientRegion)
                                    .build();

            // Verify that assuming the role worked and the permissions are set correctly
            // by getting a set of object keys from the bucket.
            ObjectListing objects = s3Client.listObjects(bucketName);
            System.out.println("No. of Objects: " + objects.getobjectSummaries().size());
        }
        catch(AmazonServiceException e) {
            // The call was transmitted successfully,but Amazon S3 Couldn't process 
            // it,so it returned an error response.
            e.printstacktrace();
        }
        catch(SdkClientException e) {
            // Amazon S3 Couldn't be contacted for a response,or the client
            // Couldn't parse the response from Amazon S3.
            e.printstacktrace();
        }
    }
}

以上代码仅在不提供某些凭据的情况下起作用。所以我的问题是，当我仅使用访问/秘密密钥时，角色在这里有什么用？

解决方法

您刚才提到的凭据是临时的，这正是建议使用IAM角色的众多原因之一。

角色可以应用于AWS服务以及资源，例如，EC2实例可以具有与AWS关联的角色，这些角色会自动轮流这些服务。另外，您可以使用STS承担角色，可以从IAM用户，角色或federated user承担角色。

您应尽量避免使用IAM用户，这有一些用例，例如已签名的URL（您希望它持续几个小时以上）以及在本地位置。如果必须使用IAM密钥，则应确保经常旋转密钥。

有关更多信息，请查看IAM Identities (users,groups,and roles)和Security best practices in IAM页面。