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

Scale out a cluster

  1. Log on to the Alibaba Cloud E-MapReduce console.
  2. In the top navigation bar, select the region where your cluster resides.
  3. Click the Cluster Management tab.
  4. Find the target cluster and click Details in the Actions column.
  5. On the Cluster Overview page that appears, select Scale Out from the Change Configuration drop-down list in the upper-right corner.
  6. In the Scale Out dialog box that appears, click CORE (Core Instance Group) or TASK (Task Instance Group) and specify related parameters.Scale out a cluster
    The following table uses CORE (Core Instance Group) as an example to describe the required parameters.
    Parameter Description
    VSwitch The VSwitch deployed in the cluster.
    Configure The configurations of the current 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 existing 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.Scale-out status

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. Run the following command to log on to the master node of the cluster:
    ssh root@ip.of.master

    Obtain the public IP address of the master node. For more information, see Cluster list and details.

  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 Cluster list and details.

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