An ECS instance is a virtual server with vCPUs, memory, OS, networking, and disks that you create, manage, and release through the console, API, or SDKs.
Instance configuration
Each instance is built from four components: instance type, image, storage, and network.
Instance type
Instance types offer varying combinations of compute, memory, and storage capacities to fit different use cases. Instance types must be used together with images, block storage devices, and network resources to create ECS instances that serve different purposes.
ECS provides a variety of instance families for common use scenarios. Each instance family consists of multiple instance types that each may have the following hardware specifications: vCPUs, memory, virtual GPUs (vGPUs), local storage (available for instance types with local SSDs and big data instance types), network cards, network performance (network bandwidth and packet forwarding rate), and cloud disk performance (cloud disk bandwidth and IOPS). Select appropriate instance types based on your performance, price, and workload requirements. For more information, see Classification and naming of instance types and Instance type selection.
Image
An image contains the OS and initialization data to start an instance. Alibaba Cloud provides images for Windows Server and mainstream Linux distributions. You can also create or import custom images. Alibaba Cloud Marketplace images include pre-installed runtime environments for scenarios such as website building and application development.
See Overview of images.
Storage
System disks and data disks are attached to instances to provide storage capacity. System disks store images that are used to boot instances. Each instance must have a system disk. The first time an ECS instance starts, the OS is installed and initial configurations are performed based on the image that is stored 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 more storage space for your instance, you can extend the cloud disks on the instance or attach additional cloud disks to the instance after the instance is 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 data durability. To ensure data availability, we recommend that you back up data on a regular basis. You can create snapshots of cloud disks to back up disk data. If you use local disks, implement data redundancy at the application layer to ensure data availability.
Network
Elastic network interfaces (ENIs) are virtual network interfaces that provide network connectivity and IP addresses for ECS instances deployed in virtual private clouds (VPCs). Each ECS instance in a VPC has a default ENI. You can bind ENIs to or unbind ENIs from ECS instances to allow the instances to access the Internet or communicate with other cloud resources over the internal network or the Internet. For more information, see Overview of ENIs.
During communication over the Internet, addressing can be performed by using private IP addresses and domain names. For more information, see Internal network access within VPC.
To allow an ECS instance to access or communicate over the Internet, enable public bandwidth for the instance. For more information, see Enable public bandwidth.
In addition to the preceding basic configurations, you can specify custom network configurations, security groups, OS configurations, and grouping configurations for instances. For more information, see Custom Launch.
Instance lifecycle
An instance's lifecycle spans from creation to release. During this period, the instance transitions between states based on your operations.
Instance states
Query instance states in two ways:
Console-based states: Displayed in the ECS console. See View instance information.
API-based states: Returned by DescribeInstanceStatus or DescribeInstances.
One API-based state can map to multiple console-based states. For example, the Stopped API state covers console states such as Expired and Locked.
Transitory states occur during transitions (e.g., Starting). Stable states are sustained operating modes (e.g., Running, Stopped).
The following table describes each lifecycle state.
Console-based state | API-based state | State attribute | Description |
Pending | Pending | Transitory | Instance created but not yet started. |
Starting | Starting | Transitory | Instance is starting after creation, a start, or a restart. |
Running | Running | Stable | Instance is running. Note Running does not guarantee the OS is fully up. Verify via View the health status of ECS instances. |
Expiring | Running | Stable | A subscription instance is nearing expiration but still runs normally. Renew promptly to avoid interruption. |
Stopping | Stopping | Transitory | Instance is shutting down after a stop or hibernation request. |
Stopped | Stopped | Stable | Instance is stopped — after creation (before first start), a normal stop, or hibernation. Console-created instances and those created by RunInstances start automatically. For pay-as-you-go instances in economical mode: vCPUs, memory, and the static public IP address are released and no longer billed; disks and associated EIPs remain billed. |
Expired | Stopped | Stable | A subscription instance has expired, or a pay-as-you-go instance was stopped due to overdue payment. The instance awaits release. |
Locked | Stopped | Stable | Instance is locked for security reasons. Request unlocking on the Network security control events page. |
To Be Released | Stopped | Stable | A refund has been applied for an unexpired subscription instance. |
State transitions
The following diagram shows how instances move between states.
To manage the status of ECS instances, you can perform the following operations:
After an ECS instance is created, the instance enters the Pending (Pending) state, the Starting (Starting) state, and then the Running (Running) state. You can connect to the instance to perform O&M operations. You can use different connection tools, such as SSH, RDP, and Session Manager, based on the OS of the instance. For more information, see Connect to your instance.
To perform specific operations on an ECS instance, such as replacing the OS, changing the private IP address, and changing the instance type of a pay-as-you-go instance, you must first stop the instance. After you stop an ECS instance, the instance enters the Stopping (Stopping) state and then the Stopped (Stopped) state.
If a pay-as-you-go ECS instance is stopped in economical mode, the computing resources (vCPUs and memory) and static public IP address (also known as system-assigned or auto-assigned public IP address) of the instance are released. You are no longer charged for these resources. Other resources of the instance, including the disks and the associated elastic IP address (EIP), are retained, and you are still charged for these resources.
If an ECS instance is in a state (such as Stopped) in which the instance cannot provide services, you must start the instance before you can use the instance. After you start an ECS instance, the instance enters the Starting (Starting) state and then the Running (Running) state.
In most cases, you may need to restart ECS instances for maintenance purposes, such as to apply system updates or to save and apply configurations. After you restart an ECS instance, the instance enters the Stopping (Stopping) state, the Starting (Starting) state, and then the Running (Running) state.
When an ECS instance is restarted, the instance may be moved to a new host. If you want your instance to remain on the same host, you can purchase a dedicated host and associate the instance with the host.
If you no longer require an ECS instance, you can release the instance to prevent unnecessary costs.
After an ECS instance is released, the instance ID, static public IP address, system disk, and data disks for which the Release Disk with Instance attribute is enabled are released and cannot be restored. If the instance is associated with an EIP, the EIP is automatically disassociated from the instance and retained. The data disks for which the Release Disk with Instance attribute is disabled are automatically detached from the instance and retained. Proceed with caution when you release instances. To prevent accidental release of instances, we recommend that you enable release protection for the instances.
Usage instructions
Select an instance type and an instance billing method.
Before you create an ECS instance, be familiar with the following information:
Instance families available for purchase and the inventory of instance families in the region in which you want to create an ECS instance. For more information, see Instance family overview or visit the Instance Types Available for Each Region page.
Instance billing methods. The following instance billing methods are supported: subscription, pay-as-you-go, and Spot Instance. Select an instance billing method based on your business requirements and determine whether to use resource plans, such as savings plans, to reduce costs.
Create an ECS instance.
Create a subscription instance on the Quick Launch tab. You can create a subscription ECS instance on the Quick Launch tab of the instance buy page in the ECS console within minutes. On the Quick Launch tab, only specific instance types and images are available and most configurations cannot be customized.
Custom Launch. You can customize configurations, such as the image type, instance type, storage, bandwidth, and security groups, based on your business requirements, and create an instance on the Custom Launch tab of the instance buy page in the ECS console.
Connect to an ECS instance.
You can connect to an ECS instance by using Choose a connection method, Choose a connection method, or Virtual Network Computing (VNC). For more information, see Choose a connection method.
If you did not set a logon password when you created an ECS instance, or if you forget the password, you must reset it to log on. For more information, see Reset the logon password of an instance.
Manage an ECS instance.
You can perform configuration and management operations on an ECS instance. For more information, see Manage instances.
Deploy services on an ECS instance.
You can deploy basic environments on an ECS instance. For more information, see Build software development environment.
You can deploy websites on an ECS instance. For more information, see Build a website.
You can deploy applications, such as databases and code hosting platforms, on an ECS instance. For more information, see Build an application.
Maintain and monitor an ECS instance.
If an ECS instance encounters unexpected issues, such as instance downtime, startup failures, or instance connection failures, you can use self-diagnostic tools for online troubleshooting. For more information, see Troubleshooting.
You can also use CloudOps Orchestration Service (OOS) to run scheduled or batch O&M tasks on ECS instances. For more information, see CloudOps Orchestration Service (OOS).
Change the configurations of an ECS instance.
If the configurations of an ECS instance do not meet your business requirements, you can change the configurations, including the instance type (vCPUs and memory), public bandwidth configurations, and billing methods of data disks. For more information, see Configuration change overview.
Release an ECS instance.
If you no longer require an ECS instance, you can release the instance to prevent unnecessary costs.
After an ECS instance is released, the instance ID, static public IP address, system disk, and data disks for which the Release Disk with Instance attribute is enabled are released and cannot be restored. If the instance is associated with an EIP, the EIP is automatically disassociated from the instance and retained. The data disks for which the Release Disk with Instance attribute is disabled are automatically detached from the instance and retained. Proceed with caution when you release instances. To prevent accidental release of instances, we recommend that you enable release protection for the instances. For more information, see Release an instance.
Security recommendations
Follow these practices to improve the security of your ECS instances:
Permission control: Use Resource Access Management (RAM) to control which users can manage ECS resources and what actions they can perform. See Identities.
Network security: Use VPCs to isolate services of different security levels. Use security groups to control inbound and outbound traffic. Allow internet access only when necessary.
Data integrity: ECS uses triplicate storage, secure data erasure, and CRC to protect data at rest and in transit. See Ensure data integrity.
Data confidentiality: ECS protects data at rest, in transit, and in use — covering storage, network transmission, and runtime computing confidentiality. See Ensure data confidentiality during data storage, transmission, and computing.
Monitoring and logging: Use services such as CloudMonitor and Cloud Config to monitor resource usage and performance in real time. Configure alerts for early exception detection.