When you call API operations to manage cloud resources by using Alibaba Cloud SDKs, you must configure valid credential information. The Credentials tool of Alibaba Cloud provides a set of easy-to-use features and supports various types of credentials, including the default credential, AccessKey pairs, and Security Token Service (STS) tokens. The Credentials tool helps you obtain and manage credentials. This topic describes the order based on which the Credentials tool obtains the default credential. You can develop a thorough knowledge of configuring and managing credentials in Alibaba Cloud SDKs. This ensures that you can perform operations on cloud resources in an efficient and secure manner.
Background information
A credential is a set of information that is used to prove the identity of a user. When you log on to the system, you must use a valid credential to complete identity authentication. The following types of credentials are commonly used:
The AccessKey pair of an Alibaba Cloud account or a Resource Access Management (RAM) user. An AccessKey pair is permanently valid and consists of an AccessKey ID and an AccessKey secret.
An STS token of a RAM role. An STS token is a temporary credential. You can specify a validity period and access permissions for an STS token. For more information, see What is STS?
A bearer token. It is used for identity authentication and authorization.
Prerequisites
Java 8 or later is installed.
Alibaba Cloud SDK V2.0 is installed. For more information, see Use Alibaba Cloud SDKs for Java in an IDE.
Install the Credentials tool
Install Alibaba Cloud Credentials for Java by adding the following Maven dependency:
<dependency>
<groupId>com.aliyun</groupId>
<artifactId>credentials-java</artifactId>
<version>{VERSION}</version>
</dependency>For more information about all released versions of Alibaba Cloud Credentials for Java, see ChangeLog.txt.
We recommend that you use the latest version of Alibaba Cloud Credentials for Java. This ensures that all credentials are supported.
We recommend that you use Alibaba Cloud SDK V2.0. If you do not use Alibaba Cloud SDK V2.0 but rely on the credentials-java module, you must add the following dependency. Otherwise, an error is reported to indicate that the com.aliyun.tea.TeaModel class file does not exist.
<dependency> <groupId>com.aliyun</groupId> <artifactId>tea</artifactId> <version>{VERSION}</version> </dependency>NoteFor more information about the versions of the tea package, see tea-java.
Initialize a Credentials client
You can use one of the following methods to initialize a Credentials client based on your business requirements:
If you use a plaintext AccessKey pair in a project, the AccessKey pair may be leaked due to improper permission management on the code repository. This may threaten the security of all resources within the account to which the AccessKey pair belongs. We recommend that you store the AccessKey pair in environment variables or configuration files.
We recommend that you build the Credentials client in single-instance mode. This mode not only enables the credential caching feature of the SDK, but also effectively prevents traffic control issues and waste of performance resources caused by multiple API calls.
Method 1: Use the default credential provider chain
If you do not specify a method to initialize a Credentials client, the default credential provider chain is used. For more information, see Default credential provider chain.
import com.aliyun.credentials.Client;
public class DemoTest {
public static void main(String[] args) throws Exception{
// Do not specify a method to initialize a Credentials client.
Client credentialClient = new Client();
// No value is specified for new Client().
}
}Example
Method 2: Use an AccessKey pair
You can create an AccessKey pair that is used to call API operations for your Alibaba Cloud account or a RAM user. For more information, see Create an AccessKey pair. Then, you can use the AccessKey pair to initialize a Credentials client.
An Alibaba Cloud account has full permissions on resources within the account. AccessKey pair leaks of an Alibaba Cloud account pose critical threats to the system.
Therefore, we recommend that you use an AccessKey pair of a RAM user that is granted permissions based on the principle of least privilege (PoLP) to initialize a Credentials client.
import com.aliyun.credentials.Client;
import com.aliyun.credentials.models.Config;
public class DemoTest {
public static void main(String[] args) throws Exception{
Config credentialConfig = new Config();
credentialConfig.setType("access_key");
credentialConfig.setAccessKeyId(System.getenv("ALIBABA_CLOUD_ACCESS_KEY_ID"));
credentialConfig.setAccessKeySecret(System.getenv("ALIBABA_CLOUD_ACCESS_KEY_SECRET"));
Client credentialClient = new Client(credentialConfig);
// No value is specified for new Client().
}
}Example
Method 3: Use an STS token
You can call the AssumeRole operation of STS as a RAM user to obtain an STS token. You can specify the maximum validity period of the STS token. The following example shows how to initialize a Credentials client by using an STS token. The example does not show how to obtain an STS token.
import com.aliyun.credentials.Client;
import com.aliyun.credentials.models.Config;
public class DemoTest {
public static void main(String[] args) {
Config credentialConfig = new Config();
credentialConfig.setType("sts");
// Obtain the AccessKey ID from the environment variable.
credentialConfig.setAccessKeyId(System.getenv("ALIBABA_CLOUD_ACCESS_KEY_ID"));
// Obtain the AccessKey secret from the environment variable.
credentialConfig.setAccessKeySecret(System.getenv("ALIBABA_CLOUD_ACCESS_KEY_SECRET"));
// Obtain the temporary STS token from the environment variable.
credentialConfig.setSecurityToken(System.getenv("ALIBABA_CLOUD_SECURITY_TOKEN"));
Client credentialClient = new Client(credentialConfig);
// No value is specified for new Client().
}
}Example
Method 4: Use an AccessKey pair and a RAM role
The underlying logic of this method is to use an STS token to initialize a Credentials client. After you specify the ARN of a RAM role, the Credentials tool can obtain an STS token from STS. You can also use the setPolicy method to limit the permissions of the RAM role.
import com.aliyun.credentials.Client;
import com.aliyun.credentials.models.Config;
public class DemoTest {
public static void main(String[] args) throws Exception {
Config credentialConfig = new Config();
credentialConfig.setType("ram_role_arn");
credentialConfig.setAccessKeyId(System.getenv("ALIBABA_CLOUD_ACCESS_KEY_ID"));
credentialConfig.setAccessKeySecret(System.getenv("ALIBABA_CLOUD_ACCESS_KEY_SECRET"));
// Specify the ARN of the RAM role that you want your application to assume by specifying the ALIBABA_CLOUD_ROLE_ARN environment variable. Example: acs:ram::123456789012****:role/adminrole.
credentialConfig.setRoleArn("<RoleArn>");
// Specify the role session name. You can configure the role session name as the ALIBABA_CLOUD_ROLE_SESSION_NAME environment variable.
credentialConfig.setRoleSessionName("<RoleSessionName>");
// Optional. Specify limited permissions for the RAM role. Example: {"Statement": [{"Action": ["*"],"Effect": "Allow","Resource": ["*"]}],"Version":"1"}.
credentialConfig.setPolicy("<Policy>");
// Not required, the external ID of the RAM role
// This parameter is provided by an external party and is used to prevent the confused deputy problem.
credentialConfig.setExternalId("<ExternalId>");
credentialConfig.setRoleSessionExpiration(3600);
Client credentialClient = new Client(credentialConfig);
// No value is specified for new Client().
}
}Example
Method 5: Use the RAM role of an ECS instance
ECS instances and elastic container instances can be assigned RAM roles. Programs that run on the instances can use the Credentials tool to automatically obtain an STS token for the RAM role. The STS token can be used to initialize the Credentials client.
By default, the Credentials tool accesses the metadata server of ECS in security hardening mode (IMDSv2). If an exception is thrown, the Credentials tool switches to the normal mode (IMDSv1). You can also configure the disableIMDSv1 parameter or ALIBABA_CLOUD_IMDSV1_DISABLE environment variable to specify the exception handling logic. Valid values:
false (default): The Credentials tool continues to obtain the access credential in normal mode (IMDSv1).
true: The exception is thrown and the Credentials tool continues to obtain the access credential in security hardening mode (IMDSv2).
The configurations for the metadata server determine whether the server supports the security hardening mode (IMDSv2).
In addition, you can specify ALIBABA_CLOUD_ECS_METADATA_DISABLED=true to disable access from the Credentials tool to the metadata server of ECS.
For more information about ECS instance metadata, see Obtain instance metadata.
For more information about how to attach a RAM role to an ECS instance, see the "Create an instance RAM role and attach the instance RAM role to an ECS instance" section of the Instance RAM roles topic. For more information about how to attach a RAM role to an elastic container instance, see the "Assign the instance RAM role to an elastic container instance" section of the Use an instance RAM role by calling API operations topic.
If you obtain an STS token in security hardening mode (IMDSv2), make sure that the version of credentials-java is 0.3.10 or later.
import com.aliyun.credentials.Client;
import com.aliyun.credentials.models.Config;
public class DemoTest {
public static void main(String[] args) throws Exception {
Config credentialConfig = new Config();
credentialConfig.setType("ecs_ram_role");
// Optional. Specify the name of the RAM role of the ECS instance. If you do not specify this parameter, its value is automatically obtained. To reduce the number of requests, we recommend that you specify this parameter. You can obtain the value from the ALIBABA_CLOUD_ECS_METADATA environment variable.
credentialConfig.setRoleName("<RoleName>");
// A value of true specifies that the security hardening mode (IMDSv2) is forcibly used. The default value is false, which specifies that the system first tries to obtain the access credential in security hardening mode (IMDSv2). If the access credential fails to be obtained, the normal mode (IMDSv1) is used.
// credentialConfig.setDisableIMDSv1(true);
Client credentialClient = new Client(credentialConfig);
// No value is specified for new Client().
}
}Example
Method 6: Use the RAM role of an OIDC IdP
After you attach a RAM role to a worker node in an Container Service for Kubernetes, applications in the pods on the worker node can use the metadata server to obtain an STS token the same way in which applications on ECS instances do. However, if an untrusted application is deployed on the worker node, such as an application that is submitted by your customer and whose code is not available to you, you may not want the application to use the metadata server to obtain an STS token of the RAM role attached to the worker node. To ensure the security of cloud resources and enable untrusted applications to securely obtain required STS tokens, you can use the RAM Roles for Service Accounts (RRSA) feature to grant permissions to an application based on the PoLP. In this case, the ACK cluster creates a service account OpenID Connect (OIDC) token file, associates the token file with a pod, and then injects relevant environment variables into the pod. Then, the Credentials tool uses the environment variables to call the AssumeRoleWithOIDC operation of STS and obtains an STS token of the RAM role. For more information about the RRSA feature, see Use RRSA to authorize different pods to access different cloud services.
The following environment variables are injected into the pod:
ALIBABA_CLOUD_ROLE_ARN: the ARN of the RAM role.
ALIBABA_CLOUD_OIDC_PROVIDER_ARN: the ARN of the OIDC identity provider (IdP).
ALIBABA_CLOUD_OIDC_TOKEN_FILE: the path of the OIDC token file.
Make sure that the version of credentials-java is 0.2.10 or later.
import com.aliyun.credentials.Client;
import com.aliyun.credentials.models.Config;
public class DemoTest {
public static void main(String[] args) throws Exception {
Config credentialConfig = new Config();
credentialConfig.setType("oidc_role_arn");
// Specify the ARN of the RAM role to be assumed. You can obtain the value from the ALIBABA_CLOUD_ROLE_ARN environment variable.
credentialConfig.setRoleArn("<RoleArn>");
// Specify the ARN of the OIDC IdP by specifying the ALIBABA_CLOUD_OIDC_PROVIDER_ARN environment variable.
credentialConfig.setOidcProviderArn("<OidcProviderArn>");
// Specify the path of the OIDC token file by specifying the ALIBABA_CLOUD_OIDC_TOKEN_FILE environment variable.
credentialConfig.setOidcTokenFilePath("<OidcTokenFilePath>");
// Specify the role session name. You can configure the role session name as the ALIBABA_CLOUD_ROLE_SESSION_NAME environment variable.
credentialConfig.setRoleSessionName("<RoleSessionName>");
// Optional. Specify limited permissions for the RAM role. Example: {"Statement": [{"Action": ["*"],"Effect": "Allow","Resource": ["*"]}],"Version":"1"}.
credentialConfig.setPolicy("<Policy>");
// Specify the validity period of the session.
credentialConfig.setRoleSessionExpiration(3600);
Client credentialClient = new Client(credentialConfig);
// No value is specified for new Client().
}
}Example
Method 7: Use a credential URI
The underlying logic of this method is to use an STS token to initialize a Credentials client. The Credentials tool uses the uniform resource identifier (URI) that you provide to obtain an STS token. The STS token is then used to initialize a Credentials client.
import com.aliyun.credentials.Client;
import com.aliyun.credentials.models.Config;
public class DemoTest {
public static void main(String[] args) throws Exception {
Config credentialConfig = new Config();
credentialConfig.setType("credentials_uri");
// Specify the URI of the credential in the http://local_or_remote_uri/ format. You can obtain the value from the ALIBABA_CLOUD_CREDENTIALS_URI environment variable.
credentialConfig.setCredentialsUri("<CredentialsUri>");
Client credentialClient = new Client(credentialConfig);
// No value is specified for new Client().
}
}Example
Method 8: Use a bearer token
Only Cloud Call Center allows you to use a bearer token to initialize an SDK client.
import com.aliyun.credentials.Client;
import com.aliyun.credentials.models.Config;
public class DemoTest {
public static void main(String[] args) throws Exception {
Config credentialConfig = new Config();
credentialConfig.setType("bearer");
// Specify the bearer token.
credentialConfig.setBearerToken("<BearerToken>");
Client credentialClient = new Client(credentialConfig);
// No value is specified for new Client().
}
}Example
Default credential provider chain
If you want to use different types of credentials in the development and production environments of your application, you generally need to obtain the environment information from the code and write code branches to obtain different credentials for the development and production environments. The default credential provider chain of Alibaba Cloud Credentials for Java allows you to obtain credentials for different environments based on configurations independent of the application, without the need for code modification. If you use Client client = new Client() to initialize a Credentials client without specifying an initialization method, the Credentials tool obtains the credential information in the following order:
1. Obtain the credential information from system properties
The Credentials tool first obtains the credential information from system properties. Check whether both the following attributes are specified:
alibabacloud.accessKeyIdalibabacloud.accessKeyIdSecret
If yes, they are used as the default credential. You can add the following JVM parameters to specify values for the preceding attributes when you run a Java application:
-Dalibabacloud.accessKeyId=your-access-key-id -Dalibabacloud.accessKeyIdSecret=your-access-key-secret
2. Obtain the credential information from environment variables
If no credential information is found in the system attributes, the Credentials continues to check the environment variables.
If both the ALIBABA_CLOUD_ACCESS_KEY_ID and ALIBABA_CLOUD_ACCESS_KEY_SECRET environment variables are specified, they are used as the default credential.
If ALIBABA_CLOUD_ACCESS_KEY_ID, ALIBABA_CLOUD_ACCESS_KEY_SECRET, and ALIBABA_CLOUD_SECURITY_TOKEN are specified, the STS token is used as the default credential.
3. Obtain the credential information by using the RAM role of an OIDC IdP
If no credentials with a higher priority are found, the Credentials tool checks the following environment variables that are related to the RAM role of the OIDC IdP:
ALIBABA_CLOUD_ROLE_ARN: the ARN of the RAM role.
ALIBABA_CLOUD_OIDC_PROVIDER_ARN: the ARN of the OIDC IdP.
ALIBABA_CLOUD_OIDC_TOKEN_FILE: the file path of the OIDC token.
If the preceding three environment variables are specified and valid, the Credentials tool uses the environment variables to call the AssumeRoleWithOIDC operation of STS to obtain an STS token as the default credential.
4. Obtain the credential information from the config.json file
Make sure that the version of credentials-java is 0.3.8 or later.
If no credentials with a higher priority are found, the Credentials tool attempts to load the config.json file. Default file path:
Linux:
~/.aliyun/config.jsonWindows:
C:\Users\USER_NAME\.aliyun\config.json
Do not change the preceding default paths. If you want to use this method to configure an access credential, manually create a config.json file in the corresponding path. Example:
{
"current": "default",
"profiles": [
{
"name": "default",
"mode": "AK",
"access_key_id": "<ALIBABA_CLOUD_ACCESS_KEY_ID>",
"access_key_secret": "<ALIBABA_CLOUD_ACCESS_KEY_SECRET>"
},
{
"name":"client1",
"mode":"RamRoleArn",
"access_key_id":"<ALIBABA_CLOUD_ACCESS_KEY_ID>",
"access_key_secret":"<ALIBABA_CLOUD_ACCESS_KEY_SECRET>",
"ram_role_arn":"<ROLE_ARN>",
"ram_session_name":"<ROLE_SESSION_NAME>",
"expired_seconds":3600
},
{
"name":"client2",
"mode":"EcsRamRole",
"ram_role_name":"<RAM_ROLE_ARN>"
},
{
"name":"client3",
"mode":"OIDC",
"oidc_provider_arn":"<OIDC_PROVIDER_ARN>",
"oidc_token_file":"<OIDC_TOKEN_FILE>",
"ram_role_arn":"<ROLE_ARN>",
"ram_session_name":"<ROLE_SESSION_NAME>",
"expired_seconds":3600
},
{
"name":"client4",
"mode":"ChainableRamRoleArn",
"source_profile":"<PROFILE_NAME>",
"ram_role_arn":"<ROLE_ARN>",
"ram_session_name":"<ROLE_SESSION_NAME>",
"expired_seconds":3600
}
]
}
In the config.json file, you can use mode to specify a type of credential:
AK: uses the AccessKey pair of a RAM user to obtain the credential information.
RamRoleArn: uses the ARN of a RAM role to obtain the credential information.
EcsRamRole: uses the RAM role attached to an ECS instance to obtain the credential information.
OIDC: uses the ARN of an OIDC IdP and the OIDC token file to obtain the credential information.
ChainableRamRoleArn: uses a role chain and specifies an access credential in another JSON file to obtain the credential information.
Configure other parameters based on your business requirements.
After you complete the configurations, the Credentials tool selects the credential specified by the current parameter in the configuration file and initialize the client. You can also specify the ALIBABA_CLOUD_PROFILE environment variable to specify the credential information. For example, you can set the ALIBABA_CLOUD_PROFILE environment variable to client1.
5. Obtain the credential information by using the RAM role of an ECS instance
If no credentials with a higher priority are found, the Credentials tool attempts to use the RAM role assigned to the ECS instance to obtain a credential. By default, the Credentials tool accesses the metadata server of ECS in security hardening mode (IMDSv2) to obtain the STS token of the RAM role used by the ECS instance and uses the STS token as the default credential. The Credentials tool automatically accesses the metadata server of ECS to obtain the name of the RAM role (RoleName) and then obtains the credential. Two requests are sent in this process. If you want to send only one request, add the ALIBABA_CLOUD_ECS_METADATA environment variable to specify the name of the RAM role. If an exception occurs in the security hardening mode (IMDSv2), the Credentials tool obtains the access credential in normal mode (IMDSv1). You can also configure the ALIBABA_CLOUD_IMDSV1_DISABLE environment variable to specify an exception handling logic. Valid values:
false: The Credentials tool continues to obtain the access credential in normal mode (IMDSv1).
true: The exception is thrown and the Credentials tool continues to obtain the access credential in security hardening mode.
The configurations for the metadata server determine whether the server supports the security hardening mode (IMDSv2).
In addition, you can specify ALIBABA_CLOUD_ECS_METADATA_DISABLED=true to disable access from the Credentials tool to the metadata server of ECS.
For more information about ECS instance metadata, see Obtain instance metadata.
For more information about how to attach a RAM role to an ECS instance, see the "Create an instance RAM role and attach the instance RAM role to an ECS instance" section of the Instance RAM roles topic. For more information about how to attach a RAM role to an elastic container instance, see the "Assign the instance RAM role to an elastic container instance" section of the Use an instance RAM role by calling API operations topic.
To obtain a credential in security hardening mode (IMDSv2), make sure that the version of credentials-java is 0.3.10 or later.
6. Obtain the credential information by using a credential URI
If no valid credential is obtained by using the preceding methods, the Credentials tool checks the ALIBABA_CLOUD_CREDENTIALS_URI environment variable. If this environment variable exists and specifies a valid URI, the Credentials tool initiates an HTTP requests to obtain an STS token as the default credential.
Automatic update mechanism of session credentials
Session credentials include ARNs of RAM roles (RamRoleArn), RAM roles of ECS instances, RAM roles of OIDC IdPs (OIDCRoleArn), and credential URIs. The Credentials tool provides a built-in automatic update mechanism for session credentials. After a credential is obtained from the first call, the Credentials tool stores the credential in the cache. In subsequent calls, the credential is read from the cache as long as the credential is not expired. Otherwise, the Credentials tool makes a call to obtain the credential again, and updates the credential in the cache.
For RAM roles of ECS instances, the Credentials tool updates the credential 15 minutes before the cache time-to-live (TTL) ends.