A cluster is a collection of cloud resources that are required to run containers. It associates with several server nodes, Server Load Balancer instances, Virtual Private Cloud (VPC), and other cloud resources.
A node is a server (either a virtual machine (VM) instance or a physical server) that is installed with a Docker Engine and is used to deploy and manage containers. The Agent program of Container Service is installed in a node and registered to a cluster. The quantity of nodes in a cluster is scalable.
A container is a runtime instance created using a Docker image. A single node can run multiple containers.
A Docker image is a standard packaging format of a container application. You can specify an image to deploy container applications. The image can be from the Docker Hub, Alibaba Cloud Container Hub, or your private registry. An image ID is uniquely identified by the URI of the image repository and the image tag name (the latest tag name is used by default).
An orchestration template contains definitions of a group of container services and their interconnection relationships, and can be used to deploy and manage multiple container applications. Container Service supports and extends the Docker Compose template specifications.
An application can be created by using an image or an orchestration template. Each application can contain one or more services.
A service is a group of containers defined based on the same image and configurations. It is used as a scalable microservice.
See the following figure for the associations among cluster, node, container, application, and service.
For more container related glossaries, see Docker glossary.