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Volcano Engine Function as a Service

Overview

Glossary

Glossary

This topic lists common terms in Volcano Engine Function as a Service (veFaaS) for easy reference.

Term	Description
Function	A function comprises function code and configuration. It serves as the fundamental unit for scheduling and executing code.
Function instance	The underlying Kubernetes resource that actually executes the function code.
Function ID	The unique identifier of a function.
Trigger	An event source that triggers function code execution. When an event meets specified rules in a trigger, the function is executed.
Runtime	The environment for running function code. The environment varies by programming language.
Cold start	The process of creating a function instance from scratch to handle requests. This process mainly involves downloading the function code, starting the container, and initializing the runtime. After the cold start is completed, the function instance is ready to handle subsequent requests. When there is no traffic for a period of time, instances of a function will automatically scale down to zero. When a request is received again, the function will perform a cold start.
Function revision	A snapshot of function code and configuration. A released revision is read-only and cannot be edited.
Latest revision	The latest function revision with editable function code and configuration. When a function is released based on its latest revision, the system will automatically generate a new revision number.
Online revision	The function revision that stably handles ‌trigger traffic‌ after a full release. In the canary release process, it refers to the ‌historically stable revision‌ not yet fully replaced (the one still serving <100% traffic).
Canary revision	The function revision that serves a ‌specified percentage of traffic‌ during a canary release. When its traffic ratio reaches 100%, it becomes the new online revision. For example, the fully released V1 revision is the online revision. Following code or configuration modifications, a 60% canary release of ‌V2‌ makes it the canary revision, while ‌V1‌ remains online. After the V2 revision passes verification, adjust the traffic ratio of the V2 revision to 100%. At this point, the V2 revision becomes the new online revision.
Memory specification	The amount of memory used by a single function instance during execution.
Wildcard domain	A type of domain name format that uses a wildcard character (usually ) to match all subdomains of a domain. For example, .example.com is a wildcard domain. Its core advantage lies in the ability to automatically generate an unlimited number of unique subdomains without the need for manual resolution of each subdomain, thereby enabling convenient assignment to different services or instances.

Last updated: 2026.08.19 14:06:04