You can scale out an E-MapReduce (EMR) cluster that has insufficient computing or storage resources. You can add core nodes and task nodes. By default, the configurations of an added node are the same as those of an existing node. This topic describes how to scale out a cluster.

Prerequisites

An EMR cluster is created. For more information, see Create a cluster.

Scale out a cluster

  1. Go to the Cluster Management page.
    1. Log on to the Alibaba Cloud EMR console.
    2. In the top navigation bar, select the region where you want to create a cluster. The region of a cluster cannot be changed after the cluster is created.
    3. Click the Cluster Management tab.
  2. On the Cluster Management page, find the cluster that you want to scale out and choose More > Scale Out in the Actions column.
  3. In the Scale Out dialog box, click the CORE (Core Instance Group) or TASK (Task Instance Group) tab and configure related parameters.
    expansion cluster
    The following table describes the parameters on the CORE (Core Instance Group) tab.
    Parameter Description
    Machine Group Name The name of the machine group.
    VSwitch The vSwitch of the cluster.
    Configure The configurations of the existing node group.
    Billing Method The billing method of the cluster. The billing method of a new node is the same as that of the cluster and cannot be changed. If the billing method is subscription, you can specify the subscription period for the new node.
    Core Nodes By default, the total number of your core nodes is displayed.
    Add The number of core nodes that you want to add. Click the upward or downward arrow or enter a number in the Add field.
    Note When you adjust the number, the total scale-out fee of a cluster is displayed in the lower-right corner of the Scale Out dialog box.
    E-MapReduce Service Terms Read and select the terms of service.
  4. Click OK.
  5. View the scale-out status.
    In the Instance Info section of the Cluster Overview page, click the node group on which you performed the scale-out operation to view the status of each new node on the right side. expansion

    Scaling out indicates that the node is being added. Normal indicates that the node is added to the cluster and can provide services.

Change the password

After you scale out the cluster, you can log on to the new node in SSH mode to change the password of the root user.

  1. Log on to the master node of the cluster. For more information, see Log on to a cluster.
  2. Run the following command to switch to the hadoop user: 
    su hadoop
  3. Run the following command to log on to the new node: 
    ssh <ip.of.worker>

    Obtain the private IP address of the new node. For more information, see View the cluster list and cluster details.

  4. Run the following command to change the password of the root user: 
    sudo passwd root