Glossary
A | B | C | D | E | F | G | H | I | J | K | L | M | N | O | P | Q | R | S | T | U | V | W | X | Y | Z
A
Annotation - --ingressannotation
Use --ingressannotation to specify meta data while creating HTTP Trigger and customize their behavior.
Archive
An archive is a zip file containing the source code or compiled binaries.
B
Builder Pod
Builder pod is a specialized pod that builds the source archive and generate a deployment archive.
Build Container
Builder Container compiles function source code into executable binary/files and is language-specific.
Builder Manager
In a nutshell, the builder Manager manages the builds of function source code.
Once an environment that contains a builder image is created, the builder manager will then create the Kubernetes service and deployment under the default namespace to start the environment builder. And once a package that contains a source archive is created, the builder manager talks to the environment builder to build the function’s source archive into a deploy archive for function deployment.
Build Status
Build status indicates the current build status of a package.
Build.sh
Build.sh is a shell script file that is used to create a custom package by installing third party modules present in the requirements.txt file.
C
Canary Config
A canary config is a custom resource used to configure a canary deployment for Fission functions.
Canary Deployment
Canary Deployment is a deployment strategy to deploy a new version of your Fission function to a cluster incrementally with minimal risk in a way that it gradually serves user traffic from 0% to 100%.
CEL Validation
Common Expression Language (CEL) validation rules are constraints embedded directly in Fission’s CRDs and enforced by the Kubernetes API server when an object is created or updated. They reject invalid resources early — for example, an unknown executor type, a negative scale, or a maximum scale below the minimum — without needing a separate admission webhook.
Cold Start
It is defined as the setup time that is required for a function to be up and running when it is invoked for the first time in a defined period to serve user requests.
Concurrency
Concurrency refers to the amount of requests a function should process simultaneously.
D
Deployment Archive
Deployment archive is an archive file that contains a runnable function.
Duration - Canary Config
Specifies how frequently user traffic needs to be incremented for the new version of function
E
Environment
Environments provide a runtime that is used to execute Fission functions. Fission ships pre-built environments for NodeJS, Python, Ruby, Go, PHP, and Bash, and you can also run any custom container as an environment.
Executor
Executor is responsible for spinning up function pods. It reads function information from the Fission CRDs and invokes the configured executor type to provision the pod. In v1.25.0 the executor runs as a set of controller-runtime reconcilers that watch the Function and Environment resources and the workloads they own.
Executor Type
The executor type determines how a function’s pods are provisioned and scaled.
Fission has exactly three: Pool Manager (poolmgr), which serves requests from a warm pool of generic pods for fast cold starts; New Deploy (newdeploy), which creates a Deployment, Service, and Horizontal Pod Autoscaler per function; and Container (container), which runs a user-supplied container image as the function pod.
F
Failure Threshold - Canary Config
Specifies the threshold in percentage beyond which the new version of a function is declared unhealthy.
Failure Type - Canary Config
Specifies the parameter for checking the health of the new version of a function. For now, the only supported type is status-code which is the http status code. So if a function returns a status code other than 200, it is considered to be unhealthy.
Fetcher
Fetcher pulls the source archive from the storage service and verifies the checksum of the file. After the build is complete, it uploads the deployment archive to the storage service.
Finalizer
A finalizer is a key on a Kubernetes object that blocks its deletion until a controller has done its cleanup and removed the key.
Fission’s executor adds the fission.io/function-cleanup finalizer to Functions so that a function’s pods and workloads are reliably torn down before the Function resource disappears.
Fission CLI
Fission CLI is the command line utility that allows you to interact with and operate Fission.
Fission Images
Fission Specs
Fission spec is a declarative way to manage an application’s specification.
Function
A serverless function in Fission.
Function Pod
Function pod is where a Fission function is loaded and executed. A function pod serves HTTP requests it receives from clients.
G
H
HTTP Trigger / Route
It is a type of trigger that invokes a Fission function whenever there is an HTTP request. You can specify a relative URL and HTTP method for an HTTP trigger.
I
J
K
KEDA Scaler
KEDA (Kubernetes Event-Driven Autoscaling) is the engine Fission uses to scale message-queue triggers based on queue depth.
For a keda-kind Message Queue Trigger, Fission creates a KEDA ScaledObject (and TriggerAuthentication) so the consumer scales out as messages arrive and scales to zero when the queue is empty.
Fission v1.25.0 integrates KEDA v2.20.
Kubernetes Watch Trigger
KubernetesWatchTrigger is a custom resource that watches Kubernetes resource events and invokes functions.
KubeWatcher
Kubewatcher watches the Kubernetes API and invokes functions associated with watches, sending the watch event to the function.
L
Logger
Logger is a daemonset that forwards function logs to a centralized database service for log persistence. Currently only InfluxDB is supported.
M
Max CPU
Maximum CPU to be assigned to pod (function in case of New Deploy) (In millicore, minimum 1)
Min CPU
Minimum CPU to be assigned to pod (function in case of New Deploy) (In millicore, minimum 1)
Max Memory
Maximum memory to be assigned to pod (function in case of New Deploy) (In megabyte)
Min Memory
Minimum memory to be assigned to pod (function in case of New Deploy)**(In megabyte)
Max Scale
Maximum number of pods (Uses resource inputs to configure HPA)
Min Scale
Minimum number of pods (Uses resource inputs to configure HPA)
Message Queue Trigger
A message queue trigger listens to messages in a message queue and invokes a function based on the arrival of a message in a queue.
N
New Deploy
New Deploy is a type of executor that creates a Kubernetes deployment along with a service and a Horizontal Pod Autoscalar (HPA) for function execution.
New Function - Canary Config
Specifies the name of the latest version of the function.
O
Old Function - Canary Config
Specifies the name of the current stable version of the function.
Once Only
OnceOnly is similar to a Kubernetes Job, it is useful in long-running tasks where only one request is served by one pod. Each request is assured to be served by a new pod.
P
Package
A package in fission can be a source package or a deployment package. A source package contains your source code and related libraries while a deployment package is the one that has an executable code.
Persistent Volume
A PersistentVolume (PV) is a piece of storage in the cluster that has been provisioned by an administrator or dynamically provisioned using Storage Classes.
Pool Manager
PoolManager manages pools of generic containers and function containers.
Pool Size
The size of pool i.e.: number of pods in a pool.
Q
R
Reconciler
A reconciler is a control loop (built on controller-runtime) that continuously drives the actual cluster state toward the desired state declared in a custom resource. In v1.25.0, the Fission executor runs Environment and Function reconcilers that watch the Fission CRDs and the workloads they own, re-create resources that drift, and use finalizers for clean teardown.
Requests Per Pod
RequestsPerPod denotes how many requests will be routed to each pod in Pool Manager.
Requirements.txt
This is a file that lists down all the external 3rd party modules, libraries that are required for your function to execute.
Router
Router is responsible for forwarding HTTP requests to function pods.
Runtime
S
Source Archive
Source archive is an archive file that contains the source code.
Specialization
Specialization is the step that turns a generic, pooled environment pod into a pod that runs one specific function. The fetcher loads the function’s deployment archive into the running environment pod and calls the runtime’s specialize endpoint, after which the pod is ready to serve that function’s requests. This is what makes Pool Manager cold starts fast: the pod is already warm, and only the function code needs to be loaded.
Specification
Specifications (specs) are YAML files that are used to instruct Fission CLI about what objects to create or update.
Storage Service
The storage service is the home for all archives of packages with sizes larger than 256 KB.
T
Target CPU
This is the CPU utilization limit (in percentage) based on which the HPA adds/removes pods.
Timer
A timer invokes a function periodically by sending a request to the router. Suitable for background tasks that need periodic execution.
Time Trigger
TimeTrigger invokes functions based on given cron schedule.
TLS - –ingressTLS
Set this flag to enable TLS termination while creating an ingress.
Toleration
Toleration is a mechanism in Kubernetes to influence the scheduling of pods.
Trigger
Trigger configures Fission to use an event to invoke a function.
Trigger - Canary Config
Specifies the name of the http trigger object.
U
V
Volume
A volume is Kubernetes represents a directory with data that is accessible across multiple containers in a pod.
W
Weight Increment - Canary Config
Specifies the percentage increase of user traffic towards the new version of the function.