E-MapReduce:Use the password-free feature of JindoFS SDK

Step 1: Create an instance RAM role

1. Log on to the RAM consoleRAM console with your Alibaba Cloud account.

2. In the left-side navigation pane, choose Identities > Roles.

3. On the RAM Roles page, click Create Role.

4. In the Create RAM Role panel, select Alibaba Cloud Service for Trusted entity type.

5. Click Next.

6. Enter a name in the RAM Role Name field, then select Elastic Compute Service from the Select Trusted Service drop-down list.

7. Click OK.

Step 2: Grant permissions to the RAM role

1. In the left-side navigation pane of the RAM console, choose Identities > Roles.

2. Find the RAM role you created and click its name.

3. Click Precise Permission.

4. In the panel that appears, set Type to System Policy or Custom Policy, then enter the policy name. Use the minimum permissions required for your use case. For example, AliyunOSSReadOnlyAccess grants read-only access to OSS. For write access, select a policy that includes the specific OSS actions your application needs.

   If system policies don't meet your requirements, create a custom policy with only the OSS actions your application uses. For instructions, see the "(Optional) Create a custom authorization policy" section in Implement access control by using RAM.

5. Click OK.

Step 3: Attach the RAM role to an ECS instance

1. Log on to the ECS console.

2. In the left-side navigation pane, choose Instances & Images > Instances.

3. In the top navigation bar, select the region where your instance is located.

4. Find the target instance and choose > Instance Settings > Attach/Detach RAM Role in the Actions column.

   

5. In the Bind/Unbind RAM Role dialog box, select the RAM role you created, then click OK.

Step 4: Add JindoFS SDK to the classpath

Add the JindoFS SDK JAR to your classpath. Use one of the following commands based on your environment:

Standard classpath:

export CLASSPATH=/xx/xx/jindofs-2.5.0-sdk.jar

Hadoop classpath:

HADOOP_CLASSPATH=$HADOOP_CLASSPATH:/xx/xx/jindofs-2.5.0-sdk.jar

Replace /xx/xx/jindofs-2.5.0-sdk.jar with the actual path to your SDK JAR file.

Step 5: Verify password-free access

After the RAM role is attached and the classpath configured, you can access OSS using the oss:// URI scheme. The SDK fetches credentials from the instance metadata service automatically.

Shell access

Run standard HDFS commands with an OSS path:

hdfs dfs -ls/-mkdir/-put/....... oss://<ossPath>

Hadoop FileSystem API

The following example lists files in an OSS bucket by using the Hadoop FileSystem API:

import org.apache.hadoop.conf.Configuration;
import org.apache.hadoop.fs.FileSystem;
import org.apache.hadoop.fs.LocatedFileStatus;
import org.apache.hadoop.fs.Path;
import org.apache.hadoop.fs.RemoteIterator;

import java.net.URI;

public class test {
    public static void main(String[] args) throws Exception {
        FileSystem fs = FileSystem.get(new URI("ossPath"), new Configuration());
        RemoteIterator<LocatedFileStatus> iterator = fs.listFiles(new Path("ossPath"), false);
        while (iterator.hasNext()){
            LocatedFileStatus fileStatus = iterator.next();
            Path fullPath = fileStatus.getPath();
            System.out.println(fullPath);
        }
    }
}

Replace ossPath with your actual OSS path (for example, oss://my-bucket/my-directory).