Automatically Adding Instance Nodes

When an autoscaling threshold is met, GeminiDB Cassandra instance nodes can be automatically added to reduce the server load or I/O overhead.

If you enable Auto Scale using a Huawei Cloud account, no additional configuration is required.
If you enable Auto Scale as an IAM user first time, you need to obtain the permission to create an agency.

Configuring Permissions

If you are using an IAM user, perform the following operations to configure GeminiDB and IAM permissions before you enable storage autoscaling:

Configure the GeminiDB FullAccess permission.

Configure fine-grained permissions for IAM.

For details about how to configure IAM permissions, see Creating a Custom Policy.

Custom policy in JSON format:

{
     "Version":"1.1",
     "Statement":[
         {
             "Effect":"Allow",
             "Action":[
                 "iam:permissions:listRolesForAgencyOnProject",
                 "iam:permissions:grantRoleToGroupOnProject",
                 "iam:agencies:createAgency",
                 "iam:agencies:listAgencies",
                 "iam:roles:listRoles",
                 "iam:roles:createRole"
             ]
         }
     ]
}

Create a user group and assign permissions.
You can create a user group on the IAM console and grant it custom permissions created in 2 and the security administrator role.
Create an IAM user and add it to a user group.
Log in to the IAM console using a Huawei Cloud account or as an IAM user, locate the IAM user that the target instance belongs to, and add it to the user group created in 3. The IAM user will inherit permissions of the user group.

Usage Notes

This function is now in OBT. To use it, choose Service Tickets > Create Service Ticket in the upper right corner of the console and contact the customer service.
If resources in the current region are insufficient, nodes may fail to be added.
Autoscaling is available only when your account balance is sufficient.
The instance must be in the Available status.
Once autoscaling is enabled, an agency will be created and fees will be automatically deducted.

Procedure

Log in to the Huawei Cloud console.
In the service list, choose Databases > GeminiDB.
On the Instances page, click the target instance. The Basic Information page is displayed.
In the Node Information area on the Basic Information page, click Auto Scale.

Figure 1 Auto Scale

Set autoscaling triggers and thresholds listed in Table 1.

Click to enlarge

**Table 1** Description
Parameter	Description
Auto Scale	Whether autoscaling is enabled
Percentage of Overloaded Nodes ≥	Percentage of overloaded nodes that need to be scaled out
Memory Usage ≥	Memory usage of nodes for which autoscaling is triggered
CPU Usage ≥	CPU usage of nodes for which autoscaling is triggered
Increase By	Number of nodes to be added each time
Maximum Nodes	Maximum number of nodes that can be automatically added