al2-custom-userdata.yaml

# This example NodePool will provision instances using the AL2 EKS-Optimized AMI.
# The UserData defined in spec.UserData needs to be in the MIME-multipart format,
# and will be prepended to a Karpenter managed section that will bootstrap the kubelet.
---
apiVersion: karpenter.sh/v1
kind: NodePool
metadata:
  name: default
  annotations:
    kubernetes.io/description: "General purpose NodePool for generic workloads"
spec:
  template:
    spec:
      requirements:
        - key: kubernetes.io/arch
          operator: In
          values: ["amd64"]
        - key: kubernetes.io/os
          operator: In
          values: ["linux"]
        - key: karpenter.sh/capacity-type
          operator: In
          values: ["on-demand"]
        - key: karpenter.k8s.aws/instance-category
          operator: In
          values: ["c", "m", "r"]
        - key: karpenter.k8s.aws/instance-generation
          operator: Gt
          values: ["2"]
      nodeClassRef:
        group: karpenter.k8s.aws
        kind: EC2NodeClass
        name: al2
---
apiVersion: karpenter.k8s.aws/v1
kind: EC2NodeClass
metadata:
  name: al2
  annotations:
    kubernetes.io/description: "EC2NodeClass for running Amazon Linux 2 nodes with custom user data"
spec:
  role: "KarpenterNodeRole-${CLUSTER_NAME}" # replace with your cluster name
  subnetSelectorTerms:
    - tags:
        karpenter.sh/discovery: "${CLUSTER_NAME}" # replace with your cluster name
  securityGroupSelectorTerms:
    - tags:
        karpenter.sh/discovery: "${CLUSTER_NAME}" # replace with your cluster name
  amiSelectorTerms:
    - alias: al2023@latest # Amazon Linux 2023
  userData: |
    MIME-Version: 1.0
    Content-Type: multipart/mixed; boundary="BOUNDARY"

    --BOUNDARY
    Content-Type: text/x-shellscript; charset="us-ascii"

    #!/bin/bash
    echo "Running a custom user data script"

    --BOUNDARY--