E-MapReduce:Configure hosts

Background information

java.net.UnknownHostException: emr-header-1.cluster-xxxx

Prerequisites

A Presto cluster is created on the EMR on ACK page of the EMR console. For more information, see Create a cluster.

Procedure

1. Go to the hosts.properties tab.

   1. Log on to the EMR console. In the left-side navigation pane, click EMR on ACK.

   2. On the EMR on ACK page, find the desired cluster and click Configure in the Actions column.

   3. On the Configure tab, move the pointer over the icon and select hosts.properties.

2. Add a configuration item.

   1. On the hosts.properties tab, click Add Configuration Item.

   2. In the Add Configuration Item dialog box, specify an internal IP address for the Key parameter and a hostname for the Value parameter.

      In most cases, you need to only specify the internal IP address and hostname of the node in the emr-master node group of the EMR on ECS cluster that you want to access. This way, the Presto cluster can access the Hive data of the EMR on ECS cluster.

      

      Note

      • Internal IP address: In the old EMR console, you can obtain the internal IP address on the Instances tab. In the new EMR console, you can obtain the internal IP address on the Nodes tab.

      • Hostname: You can run the hostname command on the emr-master node group to obtain the hostname.

   3. Click OK.

   4. In the dialog box that appears, configure the Execution Reason parameter and click Save.

3. Restart the Presto service.

   1. Click the Service Details tab.

   2. In the Components section, find the TrinoCoordinator and TrinoWorker components and click Restart in the Actions column.

   3. In the dialog box that appears, configure the Execution Reason parameter and click OK.

   4. In the Confirm message, click OK.

      After the Presto service is restarted, you can access Hive data.