Built-in Variables

There could be scenarios where a cluster name or specific values (based on defined cluster labels) need to be injected to a manifest dynamically as it is being deployed to the cluster. Controller's built-in variables can be leveraged for this purpose and the syntax below can be used either as part of cluster overrides or the manifest itself.

Cluster name

{{{ .global.Rafay.ClusterName }}}

For example, deploying the AWS Load Balancer Helm chart requires configuration of "clusterName". You can utilize the below cluster override to achieve that.

clusterName: {{{ .global.Rafay.ClusterName }}}

Cluster labels

{{{ .global.Rafay.ClusterLabels.<label_key> }}}

If there is a need as an example to dynamically configure "region" based on a pre-defined cluster label (e.g. "awsRegion"), you can utilize the below cluster override to achieve that.

region: {{{ .global.Rafay.ClusterLabels.awsRegion }}}

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Illustrative example

We will use the AWS Load Balancer Controller Helm chart for this example. The add-on called "aws-lb-controller" is configured with the helm chart provided by AWS. The helm chart requires that a "clusterName" be set before being deployed. By default, the value is left blank inside the chart. We will utilize a cluster override to set the value when the helm chart is deployed.

Step 1: Create Add-on

As an Admin in the console,

• Navigate to the Project
• Click on Add-Ons under Infrastructure. Select Create New Add-On from Catalog
• Search for "aws-load-balancer-controller"
• Click Create Add-On
• Provide a name for the add-on (e.g. aws=lb-controller), select the namespace
• Click Create
• Provide a version name (e.g. v1), clicck Save changes

Step 2: Create Cluster Override

• Navigate to the Project
• Click on Cluster Overrides under Infrastructure. Cluster Override page appears
• Click New Override and provide a name (e.g. aws-lb)
• Select the required File Type (Helm) and click Create
• For the Resource Selector, select the add-on for which the cluster override will be applied (e.g. aws-lb-controller)
• Select Specific Clusters as Type and select the required cluster(s) for which the cluster override will be applied
• Add the Override Value directly in the config screen as shown below

• Click Save Changes

Step 3: Deploy the Add-on

Deploy the blueprint to the cluster containing the add-on to utilize the newly created cluster override.

Step 4: Verify the cluster override has been applied to the deployment

kubectl describe pod -n kube-system aws-lb-controller-aws-load-balancer-controller-f5f6d6b47-9kjkl

Name:         aws-lb-controller-aws-load-balancer-controller-f5f6d6b47-9kjkl
Namespace:    kube-system
Priority:     0
Node:         ip-172-31-114-123.us-west-1.compute.internal/172.31.114.123
Start Time:   Mon, 18 Sep 2023 19:17:04 +0000
Labels:       app.kubernetes.io/instance=aws-lb-controller
              app.kubernetes.io/name=aws-load-balancer-controller
              envmgmt.io/workload-type=ClusterSelector
              k8smgmt.io/project=mango
              pod-template-hash=f5f6d6b47
              rep-addon=aws-lb-controller
              rep-cluster=pk0d152
              rep-drift-reconcillation=enabled
              rep-organization=d2w714k
              rep-partner=rx28oml
              rep-placement=k69rynk
              rep-project=lk5rdw2
              rep-project-name=mango
              rep-workloadid=kv6p0vm
Annotations:  kubernetes.io/psp: rafay-kube-system-psp
              prometheus.io/port: 8080
              prometheus.io/scrape: true
Status:       Running
IP:           172.31.103.206
IPs:
  IP:           172.31.103.206
Controlled By:  ReplicaSet/aws-lb-controller-aws-load-balancer-controller-f5f6d6b47
Containers:
  aws-load-balancer-controller:
    Container ID:  docker://e115a56b7444ea55bda8f2503b9b046d6fd84dbffd3cbf77090f35f35c2657ef
    Image:         602401143452.dkr.ecr.us-west-2.amazonaws.com/amazon/aws-load-balancer-controller:v2.1.3
    Image ID:      docker-pullable://602401143452.dkr.ecr.us-west-2.amazonaws.com/amazon/aws-load-balancer-controller@sha256:c7981cc4bb73a9ef5d788a378db302c07905ede035d4a529bfc3afe18b7120ef
    Ports:         9443/TCP, 8080/TCP
    Host Ports:    0/TCP, 0/TCP
    Command:
      /controller
    Args:
      --cluster-name=demo-eks-mango
      --ingress-class=alb
    State:          Running
      Started:      Mon, 18 Sep 2023 19:17:36 +0000
    Ready:          True
    Restart Count:  0
    Liveness:       http-get http://:61779/healthz delay=30s timeout=10s period=10s #success=1 #failure=2
    Environment:    <none>
    Mounts:
      /tmp/k8s-webhook-server/serving-certs from cert (ro)
      /var/run/secrets/kubernetes.io/serviceaccount from aws-lb-controller-aws-load-balancer-controller-token-dllmd (ro)
Conditions:
  Type              Status
  Initialized       True
  Ready             True
  ContainersReady   True
  PodScheduled      True
Volumes:
  cert:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  aws-load-balancer-tls
    Optional:    false
  aws-lb-controller-aws-load-balancer-controller-token-dllmd:
    Type:        Secret (a volume populated by a Secret)
    SecretName:  aws-lb-controller-aws-load-balancer-controller-token-dllmd
    Optional:    false
QoS Class:       BestEffort
Node-Selectors:  <none>
Tolerations:     node.kubernetes.io/not-ready:NoExecute op=Exists for 300s
                 node.kubernetes.io/unreachable:NoExecute op=Exists for 300s
Events:
  Type    Reason     Age    From               Message
  ----    ------     ----   ----               -------
  Normal  Scheduled  3m27s  default-scheduler  Successfully assigned kube-system/aws-lb-controller-aws-load-balancer-controller-f5f6d6b47-9kjkl to ip-172-31-114-123.us-west-1.compute.internal
  Normal  Pulling    3m26s  kubelet            Pulling image "602401143452.dkr.ecr.us-west-2.amazonaws.com/amazon/aws-load-balancer-controller:v2.1.3"
  Normal  Pulled     3m22s  kubelet            Successfully pulled image "602401143452.dkr.ecr.us-west-2.amazonaws.com/amazon/aws-load-balancer-controller:v2.1.3" in 4.252275657s
  Normal  Created    3m21s  kubelet            Created container aws-load-balancer-controller
  Normal  Started    3m21s  kubelet            Started container aws-load-balancer-controller

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