An instance group is a set of Elastic Compute Service (ECS) instances on which your application runs. You can deploy different application versions to different groups, then manage access traffic and implement canary releases by instance group.
| Term | Description |
|---|---|
| Default group | Created automatically when you create an application. Cannot be deleted. |
If you do not need to deploy multiple versions of your application for traffic management and canary release purposes, the default group is sufficient. You do not need to create additional groups.
Create an instance group
Create a custom instance group to deploy and validate a new application version without affecting production traffic.
Log on to the EDAS console.
In the left-side navigation pane, choose Application Management > Applications. In the top navigation bar, select a region. In the upper part of the Applications page, select a microservices namespace from the Microservices Namespace drop-down list. Then, click the name of the application that you want to manage.
On the Basic Information page, click the Instance Information tab, and then click Create Group in the upper-right corner.
In the Create Group dialog box, specify Group Name and Deployment Package Version, and then click Create. A message that indicates the group is created appears at the top of the page.
Add instances to an instance group
After you create an instance group, add instances to it by using one of the following methods:
Scale out -- Add new ECS instances directly to the group. For more information, see Scale out application instances in an ECS cluster.
Move an existing instance -- Transfer an instance from one group to another. See the following procedure.
Move an instance to a different group
On the Instance Information tab, find the instance that you want to move and click Change Group in the Actions column.
In the Change Group dialog box, select a value for Target Group.
If the target group runs a different application version from the instance, choose a redeployment policy:
Scenario Policy Result The target group has no deployed version. Not applicable The instance keeps its current version (for example, V1.0), and that version becomes the default for the target group. The target group runs a different version (for example, V2.0) and you want the instance to adopt it. Use Target Group Version for Re-deployment EDAS redeploys the instance with the target group version (V2.0). The target group runs a different version (for example, V2.0) but you want the instance to keep its current version (V1.0). Change Group Without Re-deployment The instance moves to the target group but continues to run V1.0. Click OK.
If the deployment package version of the instance differs from the deployment package version of the target group, a notification appears in the dialog box.
View instance groups
Log on to the EDAS console.
In the left-side navigation pane, choose Application Management > Applications. In the top navigation bar, select a region. In the upper part of the Applications page, select a microservices namespace from the Microservices Namespace drop-down list. Then, click the name of the application that you want to manage.
On the application details page, click the Instance Information tab.
The version of the latest deployed package appears next to each group name.
Instances are organized by the group to which they belong.
Configure JVM and Tomcat parameters for an instance group
You can configure Java Virtual Machine (JVM) and Tomcat parameters at the instance group level or at the application level. For application-level configuration, see Configure applications deployed in ECS clusters.
When you deploy an application, we recommend that you use the JVM, Tomcat, launch template, and Server Load Balancer (SLB) configurations of the instance group to which the application belongs.
On the application details page, click the Instance Information tab, and then click Group Settings next to the target group.
From the drop-down list, select JVM or Tomcat.
In the Group Settings dialog box, update the parameters and click Configure JVM Parameters or Configure Tomcat.
For parameter descriptions, see Configure applications deployed in ECS clusters.
Associate a launch template with an instance group
A launch template defines the configuration for new ECS instances. Associate a launch template with an instance group to streamline scale-out operations. When you scale out the group, EDAS creates instances based on the template configuration.
On the application details page, click the Instance Information tab, and then click Group Settings next to the target group.
From the drop-down list, select Instance Launch Template.
In the Group Settings dialog box, select Bind Launch Template, choose a launch template and a version, and then click Modify.
Bind an SLB instance to an instance group
Bind an SLB instance to route external traffic to the instances in a group. For scenarios and detailed steps, see Bind an SLB instance to an application.
Delete an instance group
You can delete an instance group only if it contains no instances and the group is no longer needed.
Deleted groups cannot be recovered. Exercise caution when you delete an instance group.
On the application details page, click the Instance Information tab. Find the group that you want to delete and click Delete Group on the right side.
In the Delete Group confirmation dialog box, click Delete.
References
| Task | API |
|---|---|
| Create an instance group | InsertDeployGroup |
| Scale out instances in a group | ScaleoutApplicationWithNewInstances |
| Move an instance to a different group | ChangeDeployGroup |
| Query group and application status | QueryApplicationStatus |
| Associate a launch template with an instance group to scale out instances | ScaleoutApplicationWithNewInstances |
| Update Tomcat configuration | UpdateContainerConfiguration |
| Update JVM configuration | UpdateJvmConfiguration |
| Get JVM configuration | GetJvmConfiguration |
| Bind an SLB instance to a group | BindEcsSlb |
| Delete an instance group | DeleteDeployGroup |