Creating an AS Group Quickly¶
If you are using AS for the first time, following the wizard-based process is an easy way to create an AS group, AS configuration, and AS policy.
Prerequisites¶
You have created the required VPCs, subnets, security groups, and load balancers.
You have obtained the keys for logging in to the instances added by a scaling action.
Procedure¶
Log in to the management console.
Under Computing, click Auto Scaling.
Click Create AS Group.
Set basic information about the AS group, such as Name, Max. Instances, Min. Instances, and Expected Instances. Table 1 lists the parameters.
Table 1 AS group parameters¶ Parameter
Description
Example Value
AZ
An AZ is a physical location where resources use independent power supply and networks. AZs are physically isolated but interconnected through an internal network.
If you require high availability, buy servers in different AZs.
If you require low network latency, buy servers in the same AZ.
N/A
Name
Specifies the name of the AS group to be created.
The name can contain up to 64 characters. It can include letters, digits, underscores (_), and hyphens (-).
N/A
Max. Instances
Specifies the maximum number of ECS instances in an AS group.
1
Expected Instances
Specifies the expected number of ECS instances in an AS group.
After an AS group is created, you can change this value, which will trigger a scaling action.
0
Min. Instances
Specifies the minimum number of ECS instances in an AS group.
0
VPC
Provides a network for your ECS instances.
All ECS instances in the AS group are deployed in this VPC.
N/A
Subnet
You can select up to five subnets. The AS group automatically binds all NICs to the created ECSs. The first subnet is used by the primary NIC of an ECS instance by default, and other subnets are used by extension NICs of the instance.
N/A
Load Balancing
This parameter is optional. A load balancer automatically distributes traffic across all instances in an AS group to balance their service load. It improves the fault tolerance of your applications and expands application service capabilities.
Note
Up to three load balancers can be added to an AS group.
After multiple load balancers are added to an AS group, multiple services can be concurrently listened to, thereby improving scalability. If ELB health check is selected for Health Check Method, when any one of the listeners detects that an instance becomes unhealthy, AS will replace the faulty instance with a functional one.
N/A
Instance Removal Policy
Specifies the priority for removing instances from an AS group. If specified conditions are met, scaling actions are triggered to remove instances. AS supports the following instance removal policies:
Oldest instance created from oldest AS configuration: The oldest instance created from the oldest configuration is removed from the AS group first.
Newest instance created from oldest AS configuration: The newest instance created from the oldest configuration is removed from the AS group first.
Oldest instance: The oldest instance is removed from the AS group first.
Newest instance: The newest instance is removed from the AS group first.
Note
Removing instances will preferentially ensure that the remaining instances are load balanced in AZs.
Manually added ECS instances are the last to be removed. If AS does remove a manually added instance, it only removes the instance from the AS group. It does not delete the instance. If multiple manually added instances must be removed, AS preferentially removes the earliest-added instance first.
N/A
EIP
If EIP has been selected in an AS configuration for an AS group, an EIP is automatically bound to the ECS instance added to the AS group. If you select Release, the EIP bound to an instance is released when the instance is removed from the AS group. Otherwise, the system unbinds the EIP from the instance, but does not release it when the instance is removed from the AS group.
N/A
Health Check Method
When a health check detects a faulty ECS, AS removes the faulty ECS from the AS group and adds a new one. The health check is implemented using any of the following methods:
ECS health check: checks ECS instance running status. If an instance is stopped or deleted, it is considered unhealthy. This method is selected by default. Using this method, the AS group periodically determines the running status of each ECS instance based on the health check result. If the health check results show that an instance is unhealthy, AS removes the instance from the AS group.
ELB health check: determines ECS running status using a load balancing listener. This health check method is available only when the AS group uses a load balancing listener. When a load balancing listener detects that an ECS is faulty, AS removes the ECS from the AS group.
N/A
Health Check Interval
Specifies the health check period for an AS group. You can set a proper health check interval, such as 10 seconds, 1 minute, 5 minutes, 15 minutes, 1 hour, and 3 hours based on the site requirements.
5 minutes
Advanced Settings
Configure notifications.
You can select Do not configure or Configure now.
N/A
Notification Mode
This parameter is optional. If this parameter is selected, the system will notify you of scaling action results by email after a scaling action is complete.
The mailbox is specified when you register yourself on the cloud.
N/A
Tag
If you have many resources of the same type, you can use tags to manage your resources. You can identify specified resources quickly using the tags allocated to them.
Each tag contains a key and a value. You can specify the key and value for each tag.
Key
The key must be specified.
The key must be unique to the AS group.
The key can include up to 36 characters. Only digits, letters, underscores (_), and hyphens (-) are allowed.
Value
The value is optional.
A key can have only one value.
The value can include up to 43 characters. Only digits, letters, underscores (_), and hyphens (-) are allowed.
N/A
Click Next.
On the displayed page, you can use an existing AS configuration or create an AS configuration. For details, see Creating an AS Configuration from an Existing ECS Instance and Creating an AS Configuration from a New Specifications Template.
Click Next.
(Optional) Add an AS policy to an AS group.
On the displayed page, click Add AS Policy.
Configure the required parameters, such as the Policy Type, Scaling Action, and Cooldown Period. For details, see Dynamic Scaling and Scheduled Scaling.
Note
If a scaling action is triggered by an AS policy, the cooldown period is whatever configured for that AS policy.
If a scaling action is triggered by manually changing the expected number of instances or by other actions, the cooldown period is whatever configured for the AS group.
Click Create Now.
Check the AS group, AS configuration, and AS policy information. Click Submit.