ytt-controller

ytt-controller

A YTT Carvel controller. It can fetch YTT files from:

1. Flux Sources (GitRepository/OCIRepository/Bucket)
2. ConfigMap/Secret

process those files programmatically invoking Carvel ytt and store the output in its Status section. Sveltos addon-manager can then be used to deploy the output of the ytt-controller in all selected managed clusters.

Install

kubectl apply -f https://raw.githubusercontent.com/gianlucam76/ytt-controller/main/manifest/manifest.yaml

or if you want a specific version

kubectl apply -f https://raw.githubusercontent.com/gianlucam76/ytt-controller/<tag>/manifest/manifest.yaml

Using Flux GitRepository

For instance, this Github repository https://github.com/gianlucam76/ytt-examples contains ytt files. You can use Flux to sync from it and then simply post this YttSource CRD instance. The ytt-controller will detect when Flux has synced the repo (and anytime there is a change), will programatically invoke ytt and store the outcome in its Status.Resources field.

apiVersion: extension.projectsveltos.io/v1alpha1
kind: YttSource
metadata:
  name: yttsource-flux
spec:
  namespace: flux-system
  name: flux-system
  kind: GitRepository
  path: ./deployment/

apiVersion: extension.projectsveltos.io/v1alpha1
kind: YttSource
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"extension.projectsveltos.io/v1alpha1","kind":"YttSource","metadata":{"annotations":{},"name":"yttsource-flux","namespace":"default"},"spec":{"kind":"GitRepository","name":"flux-system","namespace":"flux-system","path":"./deployment/"}}
  creationTimestamp: "2023-05-22T06:20:01Z"
  generation: 1
  name: yttsource-flux
  namespace: default
  resourceVersion: "91726"
  uid: c7ae3485-37a9-447a-9fa4-7d21a129ccf6
spec:
  kind: GitRepository
  name: flux-system
  namespace: flux-system
  path: ./deployment/
status:
  resources: |
    apiVersion: v1
    kind: Service
    metadata:
      name: sample-app
      labels:
        environment: staging
    spec:
      selector:
        app: sample-app
      ports:
      - protocol: TCP
        port: 80
        targetPort: 8080
    ---
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: sample-app
      labels:
        environment: staging
    spec:
      replicas: 1
      selector:
        matchLabels:
          environment: staging
      template:
        metadata:
          labels:
            environment: staging
        spec:
          containers:
          - name: sample-app
            image: nginx:latest
            imagePullPolicy: IfNotPresent
            ports:
            - containerPort: 8080
    ---
    apiVersion: v1
    kind: Secret
    metadata:
      name: application-settings
    stringData:
      app_mode: staging
      certificates: /etc/ssl/staging
      db_user: staging-user
      db_password: staging-password

Using ConfigMap/Secret

YttSource can also reference ConfigMap/Secret. For instance, we can create a ConfigMap whose BinaryData section contains ytt files.

tar -czf ytt.tar.gz -C ~mgianluc/go/src/github.com/gianlucam76/ytt-examples/deployment .
kubectl create configmap ytt --from-file=ytt.tar.gz=ytt.tar.gz 

Then we can have YttSource reference this ConfigMap instance

apiVersion: extension.projectsveltos.io/v1alpha1
kind: YttSource
metadata:
  name: yttsource-sample
spec:
  namespace: default
  name: ytt
  kind: ConfigMap
  path: ./

and the controller will programmatically execute ytt and store the outcome in Status.Results.

apiVersion: extension.projectsveltos.io/v1alpha1
kind: YttSource
metadata:
  annotations:
    kubectl.kubernetes.io/last-applied-configuration: |
      {"apiVersion":"extension.projectsveltos.io/v1alpha1","kind":"YttSource","metadata":{"annotations":{},"name":"yttsource-sample","namespace":"default"},"spec":{"kind":"ConfigMap","name":"ytt","namespace":"default","path":"./"}}
  creationTimestamp: "2023-05-22T06:27:31Z"
  generation: 1
  name: yttsource-sample
  namespace: default
  resourceVersion: "94517"
  uid: 4b0b4efb-57b4-4ffd-ab32-dc56fee21a09
spec:
  kind: ConfigMap
  name: ytt
  namespace: default
  path: ./
status:
  resources: |
    apiVersion: v1
    kind: Service
    metadata:
      name: sample-app
      labels:
        environment: staging
    spec:
      selector:
        app: sample-app
      ports:
      - protocol: TCP
        port: 80
        targetPort: 8080
    ---
    apiVersion: apps/v1
    kind: Deployment
    metadata:
      name: sample-app
      labels:
        environment: staging
    spec:
      replicas: 1
      selector:
        matchLabels:
          environment: staging
      template:
        metadata:
          labels:
            environment: staging
        spec:
          containers:
          - name: sample-app
            image: nginx:latest
            imagePullPolicy: IfNotPresent
            ports:
            - containerPort: 8080
    ---
    apiVersion: v1
    kind: Secret
    metadata:
      name: application-settings
    stringData:
      app_mode: staging
      certificates: /etc/ssl/staging
      db_user: staging-user
      db_password: staging-password

At this point Sveltos Kubernetes addon controller to use the output of the ytt-controller and deploy those resources in all selected managed clusters. To know more refer to Sveltos documentation

Contributing

❤️ Your contributions are always welcome! If you want to contribute, have questions, noticed any bug or want to get the latest project news, you can connect with us in the following ways:

1. Open a bug/feature enhancement on github
2. Chat with us on the Slack in the #projectsveltos channel
3. Contact Us