func-operator

A Kubernetes operator for managing middleware updates for serverless functions deployed with the func CLI. This operator monitors deployed functions and automatically rebuilds them when outdated middleware is detected, ensuring functions stay up-to-date with the latest middleware versions.

Prerequisites

• Kubernetes cluster (1.31+)
• Knative Serving installed
• Tekton Pipelines installed
• Container registry for storing function images

Installation

Install the Operator

Deploy the operator to your cluster:

kubectl apply -f https://github.com/functions-dev/func-operator/releases/latest/download/func-operator.yaml

Usage

Register a Function for Middleware Management

Create a Function custom resource to register an existing function for middleware monitoring and updates:

apiVersion: functions.dev/v1alpha1kind: Functionmetadata:
name: my-functionnamespace: defaultspec:
repository:
url: https://github.com/your-org/your-function.gitauthSecretRef:
name: git-credentialsregistry:
authSecretRef:
name: registry-credentials

Apply the resource:

kubectl apply -f function.yaml

Note: This registers an existing function with the operator for middleware management. To initially deploy a function, use the func CLI directly:

func deploy --path <function-path> --registry <registry-path>

Registry Authentication

For private registries, create a secret with registry credentials:

apiVersion: v1kind: Secretmetadata:
name: registry-credentialsnamespace: defaulttype: kubernetes.io/dockerconfigjsondata:
.dockerconfigjson: <base64-encoded-docker-config>

Or use kubectl:

kubectl create secret docker-registry registry-credentials \
--docker-server=<registry-url> \
--docker-username=<username> \
--docker-password=<password> \
--docker-email=<email>

Git Authentication

For private Git repositories, create a secret with the Git credentials:

apiVersion: v1kind: Secretmetadata:
name: git-credentialsnamespace: defaultdata:
token: <base64-encoded-access-token>

or

apiVersion: v1kind: Secretmetadata:
name: git-credentialsnamespace: defaultdata:
username: <base64-encoded-username>password: <base64-encoded-password>

Then reference it in the Function under .spec.repository.authSecretRef.name

apiVersion: functions.dev/v1alpha1kind: Functionmetadata:
name: my-functionnamespace: defaultspec:
repository:
url: https://github.com/your-org/your-function.gitauthSecretRef:
name: git-credentials

SSH Key Authentication

For SSH-based repository access, create a secret with the SSH private key:

apiVersion: v1kind: Secretmetadata:
name: git-ssh-credentialsnamespace: defaultdata:
sshPrivateKey: <base64-encoded-private-key>

Optional fields:

• sshPrivateKeyPassword: Passphrase for encrypted private keys
• known_hosts: SSH known_hosts file content for host key verification. If omitted, host key checking is skipped.

apiVersion: v1kind: Secretmetadata:
name: git-ssh-credentialsnamespace: defaultdata:
sshPrivateKey: <base64-encoded-private-key>sshPrivateKeyPassword: <base64-encoded-passphrase>known_hosts: <base64-encoded-known-hosts>

Reference it in the Function with an SSH repository URL:

apiVersion: functions.dev/v1alpha1kind: Functionmetadata:
name: my-functionnamespace: defaultspec:
repository:
url: git@github.com:your-org/your-function.gitauthSecretRef:
name: git-ssh-credentials

For public repositories accessible over SSH, no secret is needed:

apiVersion: functions.dev/v1alpha1kind: Functionmetadata:
name: my-functionnamespace: defaultspec:
repository:
url: git@github.com:your-org/your-function.git

Both SCP-style URLs (git@host:path) and standard SSH URLs (ssh://git@host/path) are supported.

Check Function Status

The Function CRD has the short name func, so you can use kubectl get func instead of kubectl get function.

Get an overview of all functions including their middleware version and pending rebuild status:

kubectl get func

View the full status of a specific function:

kubectl get func my-function -o yaml

The status will include:

• Function name and conditions
• Git information (branch, commit, last checked time)
• Deployment details (image, runtime, build time, deployer)
• Middleware status (current and available versions, auto-update settings, pending rebuild status)
• Service status (URL and readiness)

Advanced Use Cases

Functions in Monorepos

For functions located in a subdirectory of a repository (e.g., in a monorepo), use the repository.path field to specify the path to your function:

apiVersion: functions.dev/v1alpha1kind: Functionmetadata:
name: my-functionnamespace: defaultspec:
repository:
url: https://github.com/your-org/your-monorepo.gitpath: functions/my-functionauthSecretRef:
name: git-credentialsregistry:
authSecretRef:
name: registry-credentials

The operator will clone the repository and use the specified path as the function root directory.

Triggering a Reconciliation

The operator normally reconciles a Function when its spec changes. To trigger a reconciliation manually, add any annotation with the functions.knative.dev/ prefix:

kubectl annotate functionmy-function functions.knative.dev/reconcile=true

The operator will reconcile the Function and automatically remove the annotation afterwards.

Configuring Automatic Middleware Updates

The operators main responsibility it to rebuild functions when outdated middleware is detected. Anyhow this behavior can be enabled/disabled at two levels:

Operator-Level Default

Configure the operator-wide default by editing the func-operator-controller-config ConfigMap in the operators namespace (func-operator-system by default):

apiVersion: v1kind: ConfigMapmetadata:
name: func-operator-controller-confignamespace: func-operator-systemdata:
autoUpdateMiddleware: "true"# or "false" to disable by default

Per-Function Override

Individual functions can override the operator default using the autoUpdateMiddleware field:

apiVersion: functions.dev/v1alpha1kind: Functionmetadata:
name: my-functionnamespace: defaultspec:
repository:
url: https://github.com/your-org/your-function.gitautoUpdateMiddleware: false # Disable middleware updates for this function

Precedence: Function-level settings always take priority over the operator default.

Contributing

See CONTRIBUTING.md for development setup, testing, and contribution guidelines.

API Reference

Function Spec

Field	Type	Required	Description
repository.url	string	Yes	URL of the Git repository. Supports HTTPS, HTTP, SSH (ssh://), and SCP-style (git@host:path)
repository.branch	string	No	Branch of the repository
repository.path	string	No	Path to the function inside the repository. Defaults to "."
repository.authSecretRef	object	No	Reference to the auth secret for private repository authentication
registry.authSecretRef	object	No	Reference to the secret containing credentials for registry authentication
autoUpdateMiddleware	boolean	No	Defines if the operator should rebuild when outdated middleware is detected. When not specified, defaults to the operator-wide setting in the func-operator-controller-config ConfigMap (default: true). Function-level setting takes precedence over operator default

Function Status

Field	Type	Description
name	string	Function name from metadata
conditions	array	Status conditions (see below)
git.resolvedBranch	string	Git branch that is being monitored
git.observedCommit	string	Latest Git commit SHA observed
git.lastChecked	timestamp	Last time the repository was checked
deployment.image	string	Container image of the deployed function
deployment.imageBuilt	timestamp	When the current image was built
deployment.revision	string	Current revision of the deployed service
deployment.deployer	string	Tool/method used to deploy the function (e.g., "func")
deployment.runtime	string	Detected function runtime
middleware.current	string	Current middleware version in use
middleware.available	string	Latest available middleware version
middleware.autoUpdate.enabled	boolean	Whether automatic middleware updates are enabled
middleware.autoUpdate.source	string	Source of the autoUpdate setting ("function" or "operator")
middleware.pendingRebuild	boolean	Whether a rebuild is pending due to outdated middleware
middleware.lastRebuild	timestamp	Last time the function was rebuilt for middleware updates
service.url	string	URL of the function's service
service.ready	string	Whether the function's service is ready (e.g., "true", "false", "UNKNOWN")
history	array	Last 20 reconciliation events with timestamp and message

Status Conditions

Condition	Description
Ready	Summary condition that is True when all other conditions are True
SourceReady	Git source was cloned and function metadata was read successfully
Deployed	Function is deployed
MiddlewareUpToDate	Middleware is on the latest version (or intentionally skipped)
ServiceReady	Underlying service of the function is ready to serve traffic

Uninstallation

Remove the operator and CRDs:

# Undeploy operator
make undeploy
# Uninstall CRDs
make uninstall