An Elastic Compute Service (ECS) instance is a virtual server that includes basic components such as CPUs, memory, an operating system (OS), network configurations, and disks. You can use management tools provided by Alibaba Cloud such as the ECS console and ECS API to create and manage ECS instances. You can manage the status of ECS instances and their deployed applications in the same manner as you would do with local servers. You can also upgrade the capabilities (such as compute and storage capabilities) of your ECS instances as your requirements increase.

Basic instance configurations

The following basic configurations of each ECS instance determine the basic resources that the instance requires:
  • Instance type

    Instance types define the basic attributes of ECS instances, such as compute capacity, storage capacity, and networking capacity. Instance types must be used together with images, Elastic Block Storage (EBS) devices, and network resources to create ECS instances that serve different purposes.

    ECS provides a variety of instance families for typical use scenarios. Each instance family consists of multiple instance types that have different compute capabilities to suit different scenarios and different levels of requirements. For information about available instance types, see Instance families. For suggestions about how to select appropriate instance types for different scenarios, see Best practices for instance type selection.

    If you use your own local servers, you may need to purchase new or replacement hardware as your compute needs change. This is costly and inconvenient. If you use ECS instances, you need only to upgrade or downgrade their instance types when your compute needs change. For more information, see Change instance types.

  • Image

    Images contain the required information necessary to run ECS instances, such as OSs and initialization data of applications. Alibaba Cloud provides ready-to-use OS images for Windows Server and several mainstream Linux OSs. You can also create or import your own custom images to save time in making repeated configurations. In addition, image providers provide images pre-installed with a variety of runtime environments and software applications in Alibaba Cloud Marketplace. Alibaba Cloud Marketplace images are suitable for specific scenarios such as website building, application development, and visualized management. You can conveniently select Alibaba Cloud Marketplace images based on their purpose.

  • Storage

    ECS instances use their attached system disks and data disks for storage. Each instance must have a system disk attached. The first time the instance starts, the OS is installed and instance configurations are initialized based on the image on the system disk.

    Cloud disks can be used as system disks or data disks. Local disks can be used only as data disks and are available only for specific instance types, such as big data instance types and instance types with local SSDs. If you want your instances to have more storage space, you can resize their attached cloud disks or attach more cloud disks after the instances are created. For more information, see Overview and Attach a data disk.

    Business data is an important asset. Cloud disks adopt a triplicate mechanism to ensure the durability of data. To ensure that your data remains available, we recommend that you back up your data on a regular basis. You can create snapshots of cloud disks to back up disk data. If you are using local disks, you must implement data redundancy at the application layer to ensure data availability.

In addition to these basic configurations, you can customize network configurations, security groups, OS configurations, and grouping configurations for instances. For more information, see Create an instance by using the wizard.

Instance purchasing options

ECS provides a variety of instance purchasing options. You can select a purchasing option that meets your needs in different scenarios. Examples:
  • To obtain stable computing power, you can purchase subscription instances.
  • To meet dynamic computing power requirements, you can purchase pay-as-you-go instances.
  • To meet the computing power requirements of stateless applications and reduce compute costs, you can purchase preemptible instances.
  • To gain flexibility and cost-effectiveness in resource use, you can use pay-as-you-go instances in conjunction with reserved instances or savings plans.
  • To gain guaranteed access to compute resources, you can use pay-as-you-go instances in conjunction with resource assurances.

For information about more purchasing options, see Billing overview.

Usage instructions

Security suggestions

When you use cloud services, we recommend that you follow security suggestions to improve the security of cloud resources. Examples:
  • Suggestions for permission control: Use Resource Access Management (RAM) features to control which users can manage resources such as instances and what permissions to grant to the users.
  • Suggestions for security features: Use security features such as security hardening and cloud disk encryption to ensure the security of data and runtime environments.
  • Suggestions for network security: Use virtual private clouds (VPCs) to isolate services of different security levels. Use security groups to control inbound and outbound traffic for instances and allow instances access to the Internet only when required to minimize the attack surface area of resources.

For more information about how to improve the security of instances, see Best practices for security.