Using a Client to Execute Query Statements

Prerequisites

• The password of user admin has been obtained. The password of user admin is specified by the user during MRS cluster creation.
• The client has been updated.
• The Presto client has been manually installed for MRS 3.x clusters.

Procedure

1. For clusters with Kerberos authentication enabled, log in to MRS Manager and create a role with the Hive Admin Privilege permission.
2. Create a user to the Presto and Hive groups, bind the role created in 1 to the user, and download the user authentication file..
3. Upload the downloaded user.keytab and krb5.conf files to the node where the MRS client resides.
   

   For clusters with Kerberos authentication enabled, 2 to 3 must be performed. For normal clusters, start from 4.

4. Prepare a client based on service conditions and log in to the node where the client is installed.

   For example, if you have updated the client on the Master2 node, log in to the Master2 node to use the client. For details, see Using an MRS Client.

5. Run the following command to switch the user:

   sudo su - omm

6. Run the following command to switch to the client directory, for example, /opt/client.

   cd /opt/client

7. Run the following command to configure environment variables:

   source bigdata_env

8. Connect to the Presto Server. The following provides two client connection methods based on the client type.
   • Using the client provided by MRS
     • For clusters with Kerberos authentication disabled, run the following command to connect to the Presto Server of the cluster:

       presto_cli.sh

     • For clusters with Kerberos authentication disabled, run the following command to connect to the Presto Server of other clusters. In the command, ip indicates the floating IP address of the cluster Presto Server, which can be obtained by searching for PRESTO_COORDINATOR_FLOAT_IP in the Presto configuration items. port indicates the Presto Server port number and is set to 7520 by default.

       presto_cli.sh --server http://ip:port

     • For clusters with Kerberos authentication enabled, run the following command to connect to the Presto Server of the cluster:

       presto_cli.sh --krb5-config-path krb5.conf file path --krb5-principal User's principal --krb5-keytab-path user.keytab file path --user presto username

     • For clusters with Kerberos authentication enabled, run the following command to connect to the Presto Server of other clusters. In the command, ip indicates the floating IP address of the cluster Presto Server, which can be obtained by searching for PRESTO_COORDINATOR_FLOAT_IP in the Presto configuration items. port indicates the Presto Server port number and is set to 7521 by default.

       presto_cli.sh --krb5-config-path krb5.conf file path --krb5-principal User's principal --krb5-keytab-path user.keytab file path --server https://ip:port --krb5-remote-service-name Presto Server name

   • Using the native client

     The native client of Presto is Presto/presto/bin/presto in the client directory.

9. Run a query statement, for example, show catalogs;.
   

   For clusters with Kerberos authentication enabled, when querying Hive Catalog data, the user who runs the Presto client must have the permission to access Hive tables and run the grant all on table [table_name] to group hive; command in Hive beeline to grant permissions to the Hive group.

10. After the query is complete, run the following command to exit the client:

    quit;