COS Ranger Permission System Solution

Last updated: 2021-02-01 10:58:46


    Hadoop Ranger is a permission solution for big data scenarios. A user adopting the compute/storage separation mode can host data in Tencent COS. However, COS uses the CAM permission system, meaning that the user roles and permission policies could be different from those of Hadoop Ranger. Therefore, we introduce a solution to integrate COS with Ranger herein.


    • Fine-grained and Hadoop-compatible permission control, allowing users to centrally manage permissions for big data components and data hosted in cloud.
    • No need to set keys in core-site on the plugin side. Instead, keys are centrally set in COSRangerService to avoid key plaintext exposure.

    Solution Architecture

    In the Hadoop permission system, the authentication is offered by Kerberos and authorized by Ranger. On the basis of this, the following components are introduced to support the COS Ranger permission solution:

    1. COS-Ranger-Plugin: a service define plugin used on the Ranger server. It provides the COS service description, including permission types and definitions of required parameters (such as bucket and region), on the Ranger side. Once the plugin is deployed, users can set permission policies on the Ranger control panel.
    2. COSRangerService: integrates the Ranger client to periodically sync permission policies from the Ranger server, and verifies permissions locally when an authentication request is received. It also offers generation/lease renewal APIs relevant to DelegationToken of Hadoop. All APIs are defined through Hadoop IPC.
    3. COSRangerClient: COSN dynamically loads it and forwards the permission verification requests to COSRangerService.

    Environment Deployment

    • Hadoop
    • Kerberos (required if authentication is needed), ZooKeeper, and Ranger


      The components above are open-source and stable. You can install them as needed.

    Component Deployment

    Deploying COS-Ranger-Plugin

    COS-Ranger-Plugin extends the service types of the Ranger Admin console. Users can configure the COS-related permissions in the Ranger console.

    Source code download

    You can go to Github > ranger-plugin to obtain the source code.


    v1.1 or above

    Deployment directions

    1. Create a COS directory in the service definition directory in Ranger. Note that you should at least have execute and read permissions on the directory.
      a. In the Tencent Cloud EMR environment, the path is ranger/ews/webapp/WEB-INF/classes/ranger-plugins.
      b. In the self-built Hadoop environment, you can search the path of the Ranger-integrated components (such as HDFS) to find the path.
    2. Store cos-chdfs-ranger-plugin-xxx.jar in the COS directory. Note that you should at least have read permission on the JAR package.
    3. Restart Ranger.
    4. Register COS service in Ranger. A command example is as follows:
      ## Create the service. The Ranger admin account and password, as well as the Ranger service address should be specified.
      ## For the Tencent Cloud EMR cluster, the root account is the admin, and the password is the root account’s password that is set when the EMR cluster is created. You need to replace the Ranger service address with the master node IP of the EMR.
      curl -v -u${adminUser}:${adminPasswd} -X POST -H "Accept:application/json" -H "Content-Type:application/json" -d @./cos-ranger.json http://${rangerServerAddr}/service/plugins/definitions
      ## To delete a defined service, for example, the service created above, pass the service ID that is returned when you created the service.
      curl -v -u${adminUser}:${adminPasswd} -X DELETE -H "Accept:application/json" -H "Content-Type:application/json" http://${rangerServerAddr}/service/plugins/definitions/${serviceId}
    5. When the service is created successfully, you can view the COS service in the Ranger console, as shown in the following figure:
    6. Click the + icon on the right of the COS service to define the service instance. On the Edit Service page, customize the Service Name, for example, cos or cos_test, as shown in the following figure:

      Where, policy.grantrevoke.auth.users needs to be set to the name of the user that is used to launch the COSRangerService service (i.e., the user that is allowed to pull permission policies). You are advised to set it to hadoop, which can be used as the username to launch COSRangerService in subsequent operations.
    7. Click the created COS service instance to add a policy, as shown in the following figure:
    8. On the page that is displayed, configure the following parameters:
      • Bucket: bucket name, for example, examplebucket-1250000000. It can be queried in the COS console.
      • Path: path of the COS object. Note that it does not start with a slash (/).
        • include: indicates whether the permission applies to the specified path, or other paths except for the specified path.
        • recursive: indicates the permission applies to the specified path as well as the subpaths (i.e., the recursive subpaths) under it. It is usually used when the path is set to a directory.
      • Select Group/Select User: username and user group, in OR condition. That is, if either the username or user group meets the condition set, the operation is authorized.
      • Permissions:
        • Read: permission on operations such as downloading objects and querying the object metadata. It corresponds to the GET and HEAD operations in COS.
        • Write: permissions on operations such as uploading objects. It corresponds to the PUT operation in COS.
        • Delete: delete permission. It corresponds to the delete object operation in COS. To rename a path in Hadoop, you need to have delete permission on the original path and write permission on the new path.
        • List: traverse permission. It corresponds to the List Object operation in COS.

    Deploying COSRangerService

    COSRangerService is the core of the permission system. It integrates with the Ranger client to receive the authentication requests, token generation and lease renewal requests, and temp key generation requests of the Ranger client. It is also where the sensitive information (Tencent Cloud keys) are stored. Usually, it is deployed on the jump server, and only the cluster admin can perform operations and query the configurations.

    COSRangerService supports the one-master, multiple-slave HA deployment. DelegationToken can be stored to HDFS, and the master and slave nodes can be determined by ZooKeeper lock obtaining. Then, the master node will write the address to Zookeeper so that COSRangerClient can perform address routing.

    Source code download

    You can go to Github > cos-ranger-server to obtain the source code.


    v1.1 or above

    Deployment directions

    1. Copy the code of COSRangerService to several nodes of the cluster. In the production environment, the code should be copied to at least two nodes (one master node, and one slave node). As sensitive information is involved, you are advised to use jump servers or nodes with tight permission control.
    2. Modify the configuration in the cos-ranger.xml file. The following is the required modifications. For more information about the configuration items, please see the comments in the file.
    3. Modify the configuration in the ranger-cos-security.xml file. The following is the required modifications. For more information about the configuration items, please see the comments in the file.
      • ranger.plugin.cos.policy.cache.dir
    4. In the file, modify the configuration of hadoop_conf_path and java.library.path, which corresponds to the directory of the Hadoop configuration files (for example, core-site.xml and hdfs-site.xml) and hadoop native libraries, respectively.
    5. Run the following command to launch the service:
      chmod +x
      nohup ./ &> nohup.txt &
    6. If the launch failed, check whether an error message is contained in the error log.
    7. COSRangerService supports displaying the HTTP port status (port name: Default value: 9998). You can run the following command to obtain the status information, such as whether the leader is contained, and the authentication statistics:
      # Replace `` with the IP address of the device deployed with the ranger service.
      # Replace `9998` in the command with the value of ``.in the configuration file.
      curl -v

    Deploying COSRangerClient

    COSRangerClient is dynamically loaded by the Hadoop COSN plugin. It is a proxy that encapsulates all COSRangerService access requests, such as obtaining temp keys, obtaining tokens, and performing authentication.

    Source code download

    You can go to Github > cos-ranger-client to obtain the source code.


    v1.1 or above

    Deployment directions

    1. Copy the cos-ranger-client JAR package to the same directory of COSN. The JAR package version should be consistent with the major version of your Hadoop.

    2. Add the following configuration in core-site.xml:

              <!--*****Required Configuration********-->
              <!-- ZooKeeper address, from which the client can obtain the ranger-service address -->
              <!--***Optional Configuration****-->           
              <!-- Set the Kerberos credential used on the COSRangerService side. It should be the same as that configured on the COSRangerService side. If verification is not involved, you can skip this configuration. -->
            <!--***Optional Configuration****-->  
            <!-- IP address path of the Ranger server recorded in ZooKeeper. The default value is used herein. The value must the same as that configured in COSRangerService. -->

    Deploying COSN


    v5.9.0 or above

    Deployment directions

    For detailed directions on the deployment of COSN, please see Hadoop. Please note the following:

    1. If Ranger is used, the key information of fs.cosn.userinfo.secretId and fs.cosn.userinfo.secretKey does not need to be configured. COSN will obtain the temp key via COSRangerService.
    2. fs.cosn.credentials.provider needs to be set to org.apache.hadoop.fs.auth.RangerCredentialsProvider so that the verification and authentication can be performed via Ranger. The following is an example:


    1. Use Hadoop commands to perform operations related to COSN access, i.e., check whether the current operations comply with the permissions set by the root account.
      # Replace the bucket, path, and other information with that of the root account.
      hadoop fs -ls cosn://examplebucket-1250000000/doc
      hadoop fs -put ./xxx.txt cosn://examplebucket-1250000000/doc/
      hadoop fs -get cosn://examplebucket-1250000000/doc/exampleobject.txt
      hadoop fs -rm cosn://examplebucket-1250000000/doc/exampleobject.txt
    2. Use MR Job for verification. Before the verification, related services, such as Yarn and Hive, should be restarted first.


    Does Kerberos must be installed?

    Kerberos meets the authentication needs. If the cluster and users are trusted, and the purpose of the authentication is only to avoid misoperations caused by unauthorized users, you can skip installing Kerberos and only use Ranger for authentication. As a matter of fact, Kerberos also compromises performance. Therefore, you can balance your needs for security and performance. If authentication is needed, you can enable Kerberos, and then configure COSRangerService and COSRangerClient.

    What would happen if I enable Ranger, but haven’t set any policy or no policy is matched?

    If no policy is matched, the operation will be denied by default.

    Can a sub-account configure the key on the COSRangerService side?

    Yes. A sub-account with relevant permissions on the operated bucket can generate a temp key for the COSN plugin and operate relevant operations. Normally, you can grant all permissions of the bucket to the configured key.

    How can I update the temp key? Do I need to obtain it from COSRangerService every time before I access COS?

    The temp key is cached on the COSN side. It will be periodically updated asynchronously.