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Distribute Add-ons

What is Sveltos?

Sveltos is a set of Kubernetes controllers that run in the management cluster. From the management cluster, Sveltos can manage add-ons and applications on a fleet of managed Kubernetes clusters.

Sveltos comes with support to automatically discover ClusterAPI powered clusters, but it doesn't stop there. You can easily register any other cluster (on-prem, Cloud) and manage Kubernetes add-ons seamlessly.

Sveltos managing clusters

How it works?

ClusterProfile and Profile are the CustomerResourceDefinitions used to instruct Sveltos which add-ons to deploy on a set of clusters.

  • ClusterProfile: It iss a cluster-wide resource. It can match any cluster and reference any resource regardless of their namespace.

  • Profile: It is a namespace-scoped resource that is specific to a single namespace. It can only match clusters and reference resources within its own namespace.

By creating a ClusterProfile instance, you can easily deploy the below across a set of Kubernetes clusters.

  • Helm charts
  • Resources assembled with Kustomize
  • Raw Kubernetes YAML/JSON manifests

Define which Kubernetes add-ons to deploy and where:

  1. Select one or more clusters using a Kubernetes label selector;
  2. List the Kubernetes add-ons that need to be deployed on selected clusters

It is as simple as that!

Example: Kyverno ClusterProfile

The below example deploys a Kyverno helm chart in every cluster with the label selector set to env=prod.

Step 1: Register Clusters

The first step is to ensure the CAPI clusters are successfully registered with Sveltos. If you have not registered the clusters yet, follow the instructions mentioned here.

If you have already registered the CAPI clusters, ensure they are listed and ready to receive add-ons.

$ kubectl get sveltosclusters -n projectsveltos --show-labels

NAME        READY   VERSION          LABELS
cluster12   true    v1.26.9+rke2r1   sveltos-agent=present
cluster13   true    v1.26.9+rke2r1   sveltos-agent=present

Note

The CAPI clusters are registered in the projectsveltos namespace. If you register the clusters in a different namespace, update the command above.

Step 2: Add Kubernetes Label

The second step is to assign a specific label to the Sveltos Clusters to receive specific add-ons. In this example, we will assign the label env=prod.

$ kubectl label sveltosclusters cluster12 env=prod -n projectsveltos
$ kubectl label sveltosclusters cluster13 env=prod -n projectsveltos
$ kubectl get sveltosclusters -n projectsveltos --show-labels

NAME        READY   VERSION          LABELS
cluster12   true    v1.26.9+rke2r1   env=prod,sveltos-agent=present
cluster13   true    v1.26.9+rke2r1   env=prod,sveltos-agent=present

Tip

Starting v0.29.0, sveltosctl supports label assignment directly with the Sveltos cluster registration process. More details here.

Sveltos Registration

$ sveltosctl register cluster \
    --namespace=<namespace> \
    --cluster=<cluster name> \
    --fleet-cluster-context=<context name> \
    --labels=key1=value1,key2=value2 

Step 3: Create the ClusterProfile

The third step is to create a ClusterProfile Kubernetes resource and apply it to the management cluster.

cat > clusterprofile_kyverno.yaml <<EOF
apiVersion: config.projectsveltos.io/v1beta1
kind: ClusterProfile
metadata:
  name: kyverno
spec:
  clusterSelector:
    matchLabels:
      env: prod
  syncMode: Continuous
  helmCharts:
  - repositoryURL:    https://kyverno.github.io/kyverno/
    repositoryName:   kyverno
    chartName:        kyverno/kyverno
    chartVersion:     v3.2.5
    releaseName:      kyverno-latest
    releaseNamespace: kyverno
    helmChartAction:  Install
EOF
$ kubectl apply -f "clusterprofile_kyverno.yaml"

$ sveltosctl show addons

+--------------------------+---------------+-----------+----------------+---------+-------------------------------+------------------+
|         CLUSTER          | RESOURCE TYPE | NAMESPACE |      NAME      | VERSION |             TIME              | CLUSTER PROFILES |
+--------------------------+---------------+-----------+----------------+---------+-------------------------------+------------------+
| projectsveltos/cluster12 | helm chart    | kyverno   | kyverno-latest | 3.2.5   | 2023-12-16 00:14:17 -0800 PST | kyverno          |
| projectsveltos/cluster13 | helm chart    | kyverno   | kyverno-latest | 3.2.5   | 2023-12-16 00:14:17 -0800 PST | kyverno          |
+--------------------------+---------------+-----------+----------------+---------+-------------------------------+------------------+

Sveltos in action

Sveltos in action

Note

If you are not aware of the sveltosctl utility, have a look at the installation documentation found here.

More Resources

For a quick add-ons example, watch the Sveltos introduction video on YouTube.