Configure replicas

In the Replica Configuration tab, you can configure the size, networks, and storage volumes for the VM instances that VM Auto Scaling creates. You may also use the CloudInit mechanism to configure VM instances.

You can configure the following on the Replica Configuration tab:


  • Certain limitations listed on this page apply during the EA deployment and are subject to change as the product evolves.

  • During the EA phase, it is possible to delete replicas manually. Manual deletion of replicas does not remove the IP address of the replica from the Targets list (Management > Target Groups > select a Target Group and click Targets); ensure that you remove them manually from the Targets list before you delete the associated replica.

Configure VM Replicas

To configure VM replica settings, follow these steps:

  1. Go to the Replica Configuration tab in the Create VM Auto Scaling Group window and configure the Settings, Network, and Volumes tabs.

Click Clone Settings and Volumes from the drop-down list to clone the CPU Architecture, Cores, and RAM automatically from your VMs in the VDC. You can also use the slider to configure them manually.

Important: The VM Auto Scaling feature creates replicas based on the configuration. Changes to the existing configuration will only apply to new replicas but not the instances that are already running. Hence, we recommend that you configure Settings, Network, and Volumes before clicking Create to avoid any discrepancies later.

  1. Click Create to configure your VM Auto Scaling Group.

Result: Your VM Auto Scaling Group is successfully configured and can be managed via the VM Auto Scaling Manager.

Associate an Application Load Balancer (ALB)

An Application Load Balancer (ALB) from the VDC can be associated with the replica configuration. As a result, a replica can be linked to multiple target groups if a target group contains several NICs. This way an ALB ensures that the load is equally distributed among the replicas.

When you associate an ALB with a replica configuration, the ALB can use all of the VM replicas created by the VM Auto Scaling feature, which means your application can scale and receive requests from different queries based on the configured ALB.

To associate an ALB with a replica configuration, go to the Replica Configuration tab in the Create VM Auto Scaling Group window and specify the following:

  1. Target Group: Select a value from the drop-down list. You can also click Create new Target Group from the drop-down list to instantly create a new target group. When you specify a target group, the scaling process associates replicas with the target groups. The ALB checks these target groups to verify the available IP addresses to process requests.

Note: You cannot delete a target group if it is associated with the replica of the VM AutoScaling group and in use. We recommend deleting the AutoScaling group first before deleting the target group.

  1. Port: Select a value from the drop-down list to decide the port on which the queries must be redirected. It is recommended to set the port to TCP port 80. This port is used by the ALB to distribute traffic to individual replicas.

  2. Weight: The traffic is distributed proportionally to the target weight, which is the ratio of the total weight of all targets. A target with a higher weight receives a larger share of traffic. The valid range is from 1 to 256. We recommend using values in the middle range to leave room for later adjustments.


  • If you have not already configured an ALB, log in to the DCD with your username and password, drag-and-drop the Application Load Balancer from the Palette on the left side of the screen into your VDC to start configuring it. For more information about connecting your target group to an ALB, see Create Target Groups.

  • It is mandatory to define at least one network before you configure an ALB, so you can associate an ALB with the group after configuring replicas.

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