All Products
Search
Document Center

Glossary

Last Updated: Oct 25, 2018

The core concept of Elastic Container Instances (ECI) is the container group. This section introduces container groups and other important ECI concepts.

Container group

A container group is a set of containers, with shared storage and network, which can be scheduled to the same host. The lifecycle of a container group is collectively determined by all containers in the group. A container group is similar in concept to a pod in Kubernetes.

You need to allocate resources to container groups during ECI deployment. The minimum resources for a container group are 1 vCPU and 2 GB memory during ECI beta testing. The resources used by a container in a container group cannot exceed the resource limit of the group. For example, a container group allocated 1 vCPU can include two containers, each of them using 0.5 vCPU.

Network

Containers in the same container group share an IP address and port space. ECIs can currently be deployed only on Virtual Private Cloud (VPC) networks. When you create an ECI, you must specify VPC information to make sure that the network of the container group connects properly. During ECI beta testing, Elastic IP Addresses (EIP) cannot be directly bound to the ECIs. If the services running on the ECIs need to be accessed from the external network, you must create corresponding EIPs first and then bind them to the NAT Gateway.

Tag

Tags are key/value pairs that are attached to container groups. Tags must be attached to container groups at creation time. Each container group can have a maximum of 10 tags defined. Each key must be unique for a given container group. ECI tags are similar in concept to Kubernetes labels.

Image

You can specify an image from Docker Hub, Alibaba Cloud Marketplace, or Alibaba Cloud Container Registry when deploying a containerized application. An image is uniquely identified by the URI of its repository plus a tag (latest by default).

Volume

External volumes can be mounted into a specified container group. A volume has the same lifecycle as the container group into which it is mounted and takes effect only within that container group. Volumes claimed for a container group are shared by all containers in the container group.