This topic lists FAQ about environments.

What are the limits for releasing an environment?

When you release an environment, Web+ will unbind or release all resources that are owned by the environment. Unbind operations aim to remove the association between an environment and associated resources. After resources are unbound from an environment, these resources are no longer used. Web+ will call related Alibaba Cloud services to release other resources that are no longer required to avoid extra charges. Web+ performs different operations on different resources. The following lists resources and corresponding operations that are performed when you release an environment.
  • VPCs and VSwitches

    Web+ unbinds VPCs and VSwitches that are owned by the environment rather than releasing them.

  • Elastic Compute Service (ECS) instances

    Web+ uses the recycle mode by default.

    • If the recycle mode is applied to ECS instances that reside in an environment, these ECS instances are stopped without extra charges after you release the environment. You can log on to the ECS console and manage these ECS instances after you release the environment.
      Notice After an ECS instance is stopped, no charge is incurred for the vCPU, memory, and Internet IP address in the recycle mode. However, you will still be charged for disks.
    • If the release mode is applied to ECS instances that reside in an environment, Web+ releases these ECS instances after you release the environment.
  • Default security group
    • If the recycle mode is applied to ECS instances that reside in an environment, Web+ cannot release the default security group after you release the environment. This occurs because these ECS instances still exist and are linked with the default security group. You can log on to the ECS console and manage the default security group.
    • If the release mode is applied to ECS instances that reside in an environment, Web+ will release the default security group after you release the environment.
  • Server Load Balancer
    • If an SLB instance is not created by using Web+, Web+ only unbinds the SLB instance rather than releasing the SLB instance when you release an environment.
    • If an SLB instance is created by using Web+, Web+ only releases the SLB instance when the following condition is met: No listener, forwarding rule, VServer group, or attached ECS instance that is configured by other services or environments exists on the SLB instance. Otherwise, Web+ only unbinds the SLB instance.

What are the scenarios when the number of ECS instances is scaled down to zero?

These scenarios are listed as follows:
  • In an environment, both an SLB instance and multiple ECS instances exist. However, you only want to retain the SLB instance and its public IP address rather than the ECS instances.
  • For example, if the operating systems on the existing ECS instances fail to work properly due to malicious operations, you will need to reset these ECS instances. To reset the ECS instances, you can scale down the number of ECS instances to zero and then scale up ECS instances.

An SLB instance is automatically added when a scale-up event occurs. Why is an SLB instance not automatically released when a scale-down event occurs?

If an SLB instance is not created by using Web+, Web+ only unbinds the SLB instance rather than releasing the SLB instance when you release an environment.

If an SLB instance is created by using Web+, Web+ only releases the SLB instance when the following condition is met: No listener, forwarding rule, or session that is configured by other services or environments exists on the SLB instance. Otherwise, Web+ only unbinds the SLB instance.

How can I troubleshoot a health check failure?

  1. Check whether the deployment package is valid.
  2. Check whether the service port of the application is included in the health check URL.