Creating an MRS Hive Connection

Prerequisites

• You have created a data lake to connect, for example, a database or cloud service supported by DataArts Studio.
  • Before creating a DWS data connection, ensure that you have created a cluster in DWS and have the permissions required to view Key Management Service (KMS) keys.
  • Before creating an MRS HBase, MRS Hive, MRS Kafka, MRS Ranger, MRS Presto, or MRS Spark connection, ensure that you have bought an MRS cluster and selected required components.
  • Before creating an RDS data connection, ensure that you have bought an RDS DB instance. Currently, DataArts Studio supports only MySQL and PostgreSQL databases in RDS.
• The data lake to connect communicates with the DataArts Studio instance properly.
  • If the data lake is an on-premises database, a public network or a dedicated connection is required. Ensure that the host where the data source is located can access the public network and the port has been enabled in the firewall rule.
  • If the data lake is a cloud service (such as DWS and MRS), the following requirements must be met for network interconnection:
    • If the CDM cluster in the DataArts Studio instance and the cloud service are in different regions, a public network or a dedicated connection is required.
    • If the CDM cluster in the DataArts Studio instance and the cloud service are in the same region, VPC, subnet, and security group, they can communicate with each other by default. If they are in the same VPC but in different subnets or security groups, you must configure routing rules and security group rules. For details about how to configure routing rules, see configuring routes. For details about how to configure security group rules, see configuring security group rules.
    • The cloud service instance and the DataArts Studio workspace belong to the same enterprise project. If they do not, you can modify the enterprise project of the workspace.

Creating a Data Connection

1. On the DataArts Studio console, locate a workspace and click Management Center.

2. In the navigation pane, choose Manage Data Connections.
   Figure 1 Manage Data Connections
   

3. On the Manage Data Connections page, click Create Data Connection. In the displayed dialog box, select MRS Hive for Data Connection Type and set other parameters based on the descriptions in Table 1.
   Figure 2 Create Data Connection
   
   Figure 3 MRS Hive connection parameters
   

   Table 1 MRS Hive data connection

   Parameter	Mandatory	Description
   Data Connection Name	Yes	The name of the data connection to create. Data connection names can contain 1 to 50 characters. They can include only letters, numbers, underscores (_), and hyphens (-).
   Tag	No	The attribute of the data connection to create. Tags make management easier. You can set a tag or select a tag created in Tags from the drop-down list. NOTE: The name of the tag. Only letters, numbers, and underscores (_) are allowed. Tag names cannot start with underscores (_). Enter up to 100 characters.
   Cluster Name	Yes	The name of the MRS cluster. Select an MRS cluster that Hive belongs to. Only MRS clusters are supported. A Hadoop cluster can be selected only after it is managed by MRS. All the MRS clusters with the same project ID and enterprise project are displayed. If the connection fails after you select a cluster, check whether the MRS cluster can communicate with the CDM instance which functions as the agent. They can communicate with each other in the following scenarios: If the CDM cluster in the DataArts Studio instance and the MRS cluster are in different regions, a public network or a dedicated connection is required. If the Internet is used for communication, ensure that an EIP has been bound to the CDM cluster, and the MRS cluster can access the Internet and the port has been enabled in the firewall rule. If the CDM cluster in the DataArts Studio instance and the MRS cluster are in the same region, VPC, subnet, and security group, they can communicate with each other by default. If they are in the same VPC but in different subnets or security groups, you must configure routing rules and security group rules. For details about how to configure routing rules, see configuring routes. For details about how to configure security group rules, see configuring security group rules. The MRS cluster and the DataArts Studio workspace belong to the same enterprise project. If they do not, you can modify the enterprise project of the workspace.
   Connection Type	Yes	Connection type. Proxy connection is recommended. Proxy connection: An agent (CDM cluster) is used to access MRS clusters. This method supports all versions of MRS clusters. MRS API connection: MRS APIs are used to access MRS clusters. This method supports only MRS clusters of the 2.X or a later version. When you select MRS API connection, pay attention to the following restrictions: Tables and fields cannot be viewed. When the SQL editor is used to run SQL statements, the execution results can be displayed only in logs. This method is not supported by data governance functions such as DataArts Architecture, DataArts Quality, and DataArts Catalog. If a cluster managed by MRS is connected, disable OBS for DataArts Factory. When OBS is disabled, some functions (such as backup management and resource management) are restricted. NOTE: Select Proxy connection for Connection Type so that the DataArts Architecture, DataArts Quality, DataArts Catalog, and DataArts DataService components can use the MRS connection.
   Username	No	The username of the MRS cluster. This parameter is mandatory when Connection Type is set to Proxy connection. If a new MRS user is used for connection, you need to log in to Manager and change the initial password. You cannot create a data connection for an MRS security cluster as user admin. User admin is the management page user by default and cannot be used as the authentication user of a security cluster. You can create an MRS user by referring to Creating a Kerberos Authentication User for an MRS Security Cluster. When creating an MRS data connection, set Username and Password to the new MRS username and password. NOTE: For clusters of MRS 3.1.0 or later, the user must at least have permissions of the Manager_viewer role to create data connections in Management Center. To perform database, table, and data operations on components, the user must also have user group permissions of the components. For clusters earlier than MRS 3.1.0, the user must have permissions of the Manager_administrator or System_administrator role to create data connections in Management Center. A user with only the Manager_tenant or Manager_auditor permission cannot create connections.
   Password	No	The password for accessing the MRS cluster. This parameter is mandatory when Connection Type is set to Proxy connection.
   KMS Key	No	The name of the KMS key. This parameter is mandatory when Connection Type is set to Proxy connection.
   Agent	No	This parameter is mandatory when Connection Type is set to Proxy connection. MRS is not a fully managed service and cannot be directly connected to DataArts Studio. A CDM cluster can provide an agent for DataArts Studio to communicate with non-fully-managed services. Therefore, you need to select a CDM cluster when creating an MRS data connection. If no CDM cluster is available, create one through the DataArts Migration incremental package. As a network proxy, the CDM cluster must be able to communicate with the MRS cluster. To ensure network connectivity, the CDM cluster must be in the same region, AZ, VPC, and subnet as the MRS cluster. The security group rule must also allow the CDM cluster communicate with the MRS cluster.

4. Click Test to test connectivity of the data connection. If the test fails, the data connection fails to be created.
5. After the test is successful, click OK to create the data connection.

Reference

1. Why is no MRS Hive cluster available in the dialog box for creating a data connection?
   Possible causes are as follows:

   • Hive/HBase components were not selected during MRS cluster creation.
   • The network between the CDM cluster and MRS cluster was disconnected when an MRS data connection is created.

     The CDM cluster functions as a network agent. MRS data connections that you are going to create need to communicate with CDM.

2. Why does a Hive data connection fail to obtain information about databases or tables?

   The possible cause is that the CDM cluster is stopped or a concurrency conflict occurs. You can switch to another agent to temporarily avoid this issue.