Help Center > > User Guide> Managing an Existing Cluster> Manually Scaling Out a Cluster

Manually Scaling Out a Cluster

Updated at: Mar 25, 2021 GMT+08:00

The storage and computing capabilities of MRS can be improved by simply adding Core nodes or Task nodes instead of modifying system architecture, reducing O&M costs. Core nodes can process and store data. You can add Core nodes to expand the node quantities and handle peak loads. Task nodes are used for computing and do not store persistent data. You do not need to update the client after scaling out the cluster.

Background

An MRS cluster supports a maximum of 502 nodes. By default, there is one or two Master nodes and one Core node. The total number of Core and Task nodes cannot exceed 500.

Core nodes and Task nodes can be added, excluding the Master node. Here, the maximum number of Core/Task nodes to be added is 500 minus the number of Core/Task nodes. For example, the current number of Core nodes is 3, the number of Core nodes to be added must be less than or equal to 497. If the cluster scale-out fails, you can add node to the cluster again.

The operations for scaling out a cluster vary depending on the selected version.

Scaling Out a Cluster Billed in Pay-per-Use Mode

  1. Log in to the MRS management console.
  2. Choose Clusters > Active Clusters, select a running cluster, and click its name to switch to the cluster details page.
  3. Click the Nodes tab. In the Operation column of the node group, click Scale Out. The Scale Out page is displayed.

    The scale-out operation can only be performed on the running clusters.

  4. Set the type of the System Disk and Data Disk, Scale-Out Nodes, Enable Components and Run Bootstrap Action, and click OK. The Enable Components and Run Bootstrap Action parameters are supported only by clusters of MRS 2.x or earlier.

    • If the Task node group does not exist in the cluster, configure the Task node by referring to Related Tasks.
    • If a bootstrap action is added during cluster creation, the Run Bootstrap Action parameter is valid. If this function is enabled, the bootstrap actions added during cluster creation will be run on all the scaled out nodes. Bootstrap actions are supported only in MRS 1.7.1 or later.
    • If the New Specifications parameter is available, the specifications that are the same as those of the original nodes have been sold out or discontinued. Nodes with new specifications will be added.
    • Before scaling out the cluster, check whether its security group configuration is correct. Ensure that an inbound security group rule contains a rule in which Protocol & Port is set to All, and Source is set to a trusted accessible IP address range.

  5. In the Add Node dialog box, click OK.
  6. A dialog box is displayed in the upper right corner of the page, indicating that the scale-out task is submitted successfully.

    The following parameters explain the cluster scale-out process:
    • During scale-out: If a cluster is being scaled out, its status is Scaling out. The submitted jobs will be executed and you can submit new jobs. You are not allowed to continue to scale out or terminate the cluster. You are advised not to restart the cluster or modify the cluster configuration.
    • Successful scale-out: The cluster status is Running. The resources used in the old nodes and expanded nodes are charged.
    • Failed scale-out: The cluster status is Running. You can execute jobs and scale out the cluster again.

    After the cluster is scaled out, you can view the node information of the cluster on the Nodes tab page of the cluster details page.

Scaling Out a Cluster Billed in Yearly/Monthly Mode

  1. Log in to the MRS management console.
  2. Choose Clusters > Active Clusters, select a running cluster, and click its name to switch to the cluster details page.
  3. Click the Nodes tab. In the Operation column of the node group, click Scale Out. The Scale Out page is displayed.

    The scale-out operation can only be performed on the running clusters.

  4. Set the type of the System Disk and Data Disk, Scale-Out Nodes, Enable Components and Run Bootstrap Action. The system displays the expiration time of the cluster and the fee required for adding nodes. The Enable Components and Run Bootstrap Action parameters are supported only by clusters of MRS 2.x or earlier.

    • If a bootstrap action is added during cluster creation, the Run Bootstrap Action parameter is valid. If this function is enabled, the bootstrap actions added during cluster creation will be run on all the scaled out nodes. Bootstrap actions are supported only in MRS 1.7.1 to 2.x.
    • If the New Specifications parameter is available, the specifications that are the same as those of the original nodes have been sold out or discontinued. Nodes with new specifications will be added.
    • Before scaling out the cluster, check whether its security group configuration is correct. Ensure that an inbound security group rule contains a rule in which Protocol & Port is set to All, and Source is set to a trusted accessible IP address range.
    • Click Submit Order.

    On the Purchase MapReduce Service page, click Pay.

    • Click Confirm order, not pay.

    On the cluster information page, choose Fee > My Order and click Pay.

  5. After the payment is successful, return to the MRS management console to view the cluster status.

    The following parameters explain the cluster scale-out process:
    • During scale-out: If a cluster is being scaled out, its status is Scaling out. The submitted jobs will be executed and you can submit new jobs. You are not allowed to continue to scale out or terminate the cluster. You are advised not to restart the cluster or modify the cluster configuration.
    • Successful scale-out: The cluster status is Running. The resources used in the old nodes and expanded nodes are charged.
    • Failed scale-out: The cluster status is Running. You can execute jobs and scale out the cluster again.

    After the cluster is scaled out, you can view the node information of the cluster on the Nodes tab page of the cluster details page.

Configuring Task Node

To add a Task node, perform the following steps:
  1. On the cluster details page, click the Nodes tab and click Configure Task Node. The Configure Task Node page is displayed.
  2. On the Configure Task Node page, set Node Type, Instance Specifications, Nodes, System Disk. In addition, if Add Data Disk is enabled, configure the storage type, size, and number of data disks.
  3. Click OK.

Adding a Node Group

Used to add node groups and applies to customized clusters of MRS 3.x.

  1. On the cluster details page, click the Nodes tab and click Add Node Group. The Add Node Group page is displayed.
  2. Set the parameters as needed.
  3. Click OK.

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