EKS - Node labels

With the new EKS-optimized AMIs(amazon-eks-node-vXX) and Cloudformation template refactors provided by AWS it is now possible to add node labels as simple as providing arguments to the BootstrapArguments parameter of the [amazon-eks-nodegroup.yaml][1] Cloudfomation template. For example --kubelet-extra-args --node-labels=my-key=my-value. For more details check the AWS announcement: Improvements for Amazon EKS Worker Node Provisioning

You'll need to add the config in user_data and use the --node-labels option for the kubelet. Here's an example user_data which includes node_labels:

NodeLaunchConfig:
Type: AWS::AutoScaling::LaunchConfiguration
Properties:
  AssociatePublicIpAddress: 'true'
  IamInstanceProfile: !Ref NodeInstanceProfile
  ImageId: !Ref NodeImageId
  InstanceType: !Ref NodeInstanceType
  KeyName: !Ref KeyName
  SecurityGroups:
  - !Ref NodeSecurityGroup
  UserData:
    Fn::Base64:
      Fn::Join: [
        "",
        [
          "#!/bin/bash -xe\n",
          "CA_CERTIFICATE_DIRECTORY=/etc/kubernetes/pki", "\n",
          "CA_CERTIFICATE_FILE_PATH=$CA_CERTIFICATE_DIRECTORY/ca.crt", "\n",
          "MODEL_DIRECTORY_PATH=~/.aws/eks", "\n",
          "MODEL_FILE_PATH=$MODEL_DIRECTORY_PATH/eks-2017-11-01.normal.json", "\n",
          "mkdir -p $CA_CERTIFICATE_DIRECTORY", "\n",
          "mkdir -p $MODEL_DIRECTORY_PATH", "\n",
          "curl -o $MODEL_FILE_PATH https://s3-us-west-2.amazonaws.com/amazon-eks/1.10.3/2018-06-05/eks-2017-11-01.normal.json", "\n",
          "aws configure add-model --service-model file://$MODEL_FILE_PATH --service-name eks", "\n",
          "aws eks describe-cluster --region=", { Ref: "AWS::Region" }," --name=", { Ref: ClusterName }," --query 'cluster.{certificateAuthorityData: certificateAuthority.data, endpoint: endpoint}' > /tmp/describe_cluster_result.json", "\n",
          "cat /tmp/describe_cluster_result.json | grep certificateAuthorityData | awk '{print $2}' | sed 's/[,\"]//g' | base64 -d >  $CA_CERTIFICATE_FILE_PATH", "\n",
          "MASTER_ENDPOINT=$(cat /tmp/describe_cluster_result.json | grep endpoint | awk '{print $2}' | sed 's/[,\"]//g')", "\n",
          "INTERNAL_IP=$(curl -s http://169.254.169.254/latest/meta-data/local-ipv4)", "\n",
          "sed -i s,MASTER_ENDPOINT,$MASTER_ENDPOINT,g /var/lib/kubelet/kubeconfig", "\n",
          "sed -i s,CLUSTER_NAME,", { Ref: ClusterName }, ",g /var/lib/kubelet/kubeconfig", "\n",
          "sed -i s,REGION,", { Ref: "AWS::Region" }, ",g /etc/systemd/system/kubelet.service", "\n",
          "sed -i s,MAX_PODS,", { "Fn::FindInMap": [ MaxPodsPerNode, { Ref: NodeInstanceType }, MaxPods ] }, ",g /etc/systemd/system/kubelet.service", "\n",
          "sed -i s,MASTER_ENDPOINT,$MASTER_ENDPOINT,g /etc/systemd/system/kubelet.service", "\n",
          "sed -i s,INTERNAL_IP,$INTERNAL_IP,g /etc/systemd/system/kubelet.service", "\n",
          "DNS_CLUSTER_IP=10.100.0.10", "\n",
          "if [[ $INTERNAL_IP == 10.* ]] ; then DNS_CLUSTER_IP=172.20.0.10; fi", "\n",
          "sed -i s,DNS_CLUSTER_IP,$DNS_CLUSTER_IP,g  /etc/systemd/system/kubelet.service", "\n",
          "sed -i s,CERTIFICATE_AUTHORITY_FILE,$CA_CERTIFICATE_FILE_PATH,g /var/lib/kubelet/kubeconfig" , "\n",
          "sed -i s,CLIENT_CA_FILE,$CA_CERTIFICATE_FILE_PATH,g  /etc/systemd/system/kubelet.service" , "\n"
          "sed -i s,INTERNAL_IP/a,--node-labels tier=development,g  /etc/systemd/system/kubelet.service" , "\n"
          "systemctl daemon-reload", "\n",
          "systemctl restart kubelet", "\n",
          "/opt/aws/bin/cfn-signal -e $? ",
          "         --stack ", { Ref: "AWS::StackName" },
          "         --resource NodeGroup ",
          "         --region ", { Ref: "AWS::Region" }, "\n"
        ]
      ]

The relevant line is:

"sed -i s,INTERNAL_IP/a,--node-labels tier=development,g  /etc/systemd/system/kubelet.service" , "\n"

WARNING: I haven't tested this, but I do something similar and it works fine