ENS:Deployment and Elasticity

Deployment strategy

A deployment strategy determines how instances are deployed on physical servers. ENS currently supports the high availability strategy.

The high availability strategy distributes instances within a deployment set across different physical servers, reducing the risk of service interruptions caused by single-server failures. This strategy is suited for small-scale deployments that require high service continuity and fault isolation.

Limitations

• Each Alibaba Cloud account can have a maximum of 20 deployment sets.

• A single deployment set can contain a maximum of 20 instances per node.

• Deployment sets cannot be merged.

• Only X86 instances are supported.

• If a deployment set has too many instances on a single node, the node may lack sufficient redundant physical servers. This can cause instance creation, resizing, or migration to fail. In this case, the system returns the error: Cannot complete creation/resizing/migration because the deployment set policy requirements are not met.

Create a deployment set

1. Log on to the ENS console.

2. In the left navigation pane, choose Deployment & Elasticity > Deployment Set. On the Deployment Set page, click Create Deployment Set.

3. In the Create Deployment Set dialog, configure the following parameters, then click OK.

4. After you click OK, the new deployment set appears in the Deployment Sets list.

Create an instance in a deployment set

1. On the Deployment Set page, find the target deployment set.

2. In the Actions column, click Create Instance.

3. Complete the instance configuration on the purchase page.

4. After creation, the instance appears in the instance list of the deployment set.

Adjust the deployment set of an instance

Transfer an instance to a different deployment set, or add an instance that is not in any deployment set to a target deployment set.

1. Log on to the ENS console.

2. In the left navigation pane, click Instances.

3. Find the target instance. In the Actions column, click to expand more actions, then click Modify Instance Deployment Set.

4. In the Adjust Deployment Set dialog, select a Target Deployment Set, then click OK.

5. Refresh the page. The Deployment Set column of the instance shows the new deployment set name.

Remove an instance from a deployment set

If you want to delete a deployment set while retaining its instances, remove the instances first. The instances retain their current state after removal.

1. Log on to the ENS console.

2. In the left navigation pane, click Instances.

3. Find the target instance. In the Actions column, click to expand more actions, then click Remove from Deployment Set.

4. In the confirmation dialog, click OK.

5. Refresh the page. The instance no longer appears in the deployment set's instance list.

Edit or delete a deployment set

1. Log on to the ENS console.

2. In the left navigation pane, choose Deployment & Elasticity > Deployment Set. On the Deployment Set page, find the target deployment set. In the Actions column, click Edit or Delete, then follow the on-screen instructions.

   • Edit: Modify the deployment set name and description. The updated name or description takes effect immediately.

   • Delete: Delete a deployment set you no longer need to free up resources. The deployment set is removed from the list.