If you have a large number of instances, you can add tags to them to facilitate unified management and allow you to group different instances easily.
To add a tag to an instance, perform the following:
Log on to the ECS console.
In the left-side navigation pane, click Instances.
Select a region.
Select one or more instances, and then select More > Edit Tags.
In the dialog box, click Create.
Enter your custom tag key and value, and then click Confirm.
Your tag will then be added to the available tag selection. Click Confirm to add the created tag to the instance.