This topic provides an overview of Elastic Compute Service (ECS) features to help you better understand and use ECS.

Instance

An ECS instance is a cloud-based virtual computing server that includes basic components such as vCPUs, 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 with local servers. You can also upgrade the computing, storage, and other capabilities of your ECS instances as your requirements increase.

ECS provides a variety of instance families for different use scenarios. Each instance family consists of multiple instance types that comprise various combinations of vCPU, memory, network, and storage capacities and offer you the flexibility to choose an appropriate mix of resources based on your business requirements.
  • For information about the billing of instances, see Instance types.
  • For more information about instances, see Overview.

Image

ECS images provide the information required to create ECS instances. This information includes OS data, initialization data of applications, and pre-installed software. You must select an image when you create an ECS instance. An image is a copy of data from one or more disks.

ECS images are classified into public images, custom images, shared images, community images, and Alibaba Cloud Marketplace images based on image sources. You can select images based on multiple elements such as regions, image types, OSs, and built-in software.
  • For information about the billing of images, see Images.
  • For more information about images, see Image overview.

Elastic Block Storage (EBS)

EBS is a high-performance, low-latency block storage service provided by Alibaba Cloud and provides block-level storage devices for use with ECS. EBS devices support random reads and writes to meet your data storage requirements. EBS devices can be used in the same manner as physical hard disks. You can partition and format EBS devices and create file systems for them.

Alibaba Cloud provides a variety of EBS devices, including cloud disks that are based on a distributed storage architecture and local disks that are based on the hard disks of physical machines. ECS supports multiple disk categories that offer different performance, including enhanced SSD (ESSD), standard SSD, and ultra disk.

Snapshot

Snapshots are point-in-time backups of disks and can be used to back up data. When a disk fails, you can use a snapshot of this disk to roll back the disk. This way, the disk can be restored to the state it was in when the snapshot was created. You can use snapshots to back up critical disk data on a regular basis and eliminate the risk of data loss caused by accidental operations, attacks, or viruses.

Security group

A security group acts as a virtual firewall to control the inbound and outbound traffic of ECS instances to improve security. Rules can be added to security groups to allow or deny traffic to or from the security groups. For more information about security groups, see Overview.

Network

ECS supports two network types: classic network and Virtual Private Cloud (VPC). The classic network is a shared basic network that implements Layer 3 isolation. A VPC is a private network that is logically isolated on the cloud and implements Layer 2 isolation for increased security and flexibility. IP addresses are assigned to provide access to ECS instances and allow the instances to communicate with other Alibaba Cloud services.
  • You are charged only for outbound traffic to the Internet. For information about the billing of Internet usage, see Public bandwidth.
  • For more information about networks, see Network types.

Deployment and elasticity

You can create launch templates, deployment sets, and auto provisioning groups to allow for fast and easy provisioning and management of ECS instances.
  • A launch template stores persisted ECS instance configurations so that you do not need to make them each time you create ECS instances. For more information, see Launch templates.
  • A deployment set is a policy that controls the distribution of ECS instances. You can use a deployment set to distribute your instances across different physical servers to ensure high service availability and implement underlying disaster recovery. For more information, see Overview.
  • Auto Provisioning is a service that enables fast provisioning of ECS instances. You only need to make simple configurations to automate the creation of instances that use different billing methods (pay-as-you-go and preemptible instance) across instance types and zones. This improves the efficiency when you batch create a large number of instances. For more information, see Overview.
  • Terraform allows you to use a simple template language to define, preview, and deploy cloud infrastructure in Alibaba Cloud. For more information, see Terraform overview.

Tag and resource group

Tags allow enterprises and individuals to identify and categorize their ECS resources and simplify the search and management of the resources. For more information, see Overview.

Resource groups are used to group your resources by usage, permission, and region, so that you can manage the resources in a hierarchical manner based on users and projects. For more information, see Resource groups.

O&M and monitoring

ECS provides comprehensive diagnostics and monitoring of instance OS states, network states, disk states, and security group rules to help you identify and resolve common issues in a timely manner. For more information, see Identify and troubleshoot instance issues.

ECS supports Cloud Assistant. Cloud Assistant is a native automated O&M tool developed for ECS. It allows you to batch maintain ECS instances and batch execute scripts on and send files to ECS instances in a password-free, logon-free manner without the use of jumper servers. These scripts can be shell, PowerShell, or bat scripts. For more information, see Overview.