When you use an EMR Hadoop cluster, you need to specify the instance types for the instance groups based on the real scenarios. For example:
  • You need some memory instances (CPU: Mem = 1 vCore: 8 GiB) to perform offline big data processing and some compute instances (CPU: Mem=1 vCore: 2 GiB) to train models.
  • You want to assign certain departments with memory instances (CPU: Mem = 1 vCore: 8 GiB) and compute instances (CPU: Mem=1 vCore: 2 GiB) based on their requirements.
You can use Task instances to create multiple host groups and select different configurations for the host groups to meet the preceding requirements. Procedure:
  1. Log on to the Alibaba Cloud E-MapReduce console. Click Cluster Management to go to the cluster management page.
  2. Click Clusters and Services in the Actions column for the cluster that you want to create host groups for.
  3. In the left-side navigation pane, click Cluster Overview.
  4. On the Cluster Overview page, click Resource Allocation. From the Resource Allocation drop-down list, select Scale Up/Out.
  5. Click the TASK (Task Instance Group) tab, click Add Host Group.
  6. In the Host Group Name field, enter a name for the host group. Select the specifications as needed. A host group name is required to be unique for each cluster.

Notice You can create a maximum of 10 host groups to categorize the task instances of an EMR Hadoop cluster.