To extend or shrink the computing capacity of an application, you can resize an environment of the application by scaling out or in Elastic Compute Service (ECS) instances. You can add ECS instances to the environment when the load is too high for the existing ECS instances of the application, and delete some ECS instances when they are no longer required.

You can run the env:scale command and specify the target number of ECS instances as required to resize the environment. When the number of ECS instances increases from 1 to n, a Server Load Balancer (SLB) instance is created by default. However, when the number continues to increase from n to m, no SLB instance is added. When the number decreases from n to 0, the SLB instance is not deleted.

wpctl env:scale 2
[OK] Update environment name Web*** (1s)
...

You can run the env:info command to query the number of ECS instances after the deployment environment is resized.