This topic describes how to scale out an E-MapReduce (EMR) cluster when its computing or storage resources are insufficient. Core nodes and task nodes can be added. By default, the configurations of an added node are the same as those of an existing node.

Scale out a cluster

  1. Log on to the EMR console.
  2. In the top navigation bar, select the region where your cluster resides and select a resource group based on your business requirements.
  3. Click the Cluster Management tab.
  4. On the Cluster Management page, find your cluster and click Details in the Actions column.
  5. On the Cluster Overview page, choose Change Configuration > Scale Out in the upper-right corner.
  6. In the Scale Out dialog box, click CORE (Core Instance Group) or TASK (Task Instance Group) and specify related parameters.
    expansion cluster
    The following table uses CORE (Core Instance Group) as an example to describe the parameters.
    Parameter Description
    VSwitch The vSwitch of the cluster.
    Configure The configurations of the existing instance 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 The total number of your core nodes is displayed by default.
    Add The number of core nodes 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 fee for scaling out a cluster is displayed in the lower-right corner of the Scale Out dialog box.
    E-MapReduce Service Terms Read and agree to the service terms.
  7. Click OK.

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.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 Connect to the master node of an EMR cluster in SSH mode.
  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