tags.sh

#!/bin/bash
ARGS=${@:1}
input="./tags.txt"
tagCluster() {
  local clusterName=$1
  local region=$2
  nodeGroups=$(aws eks list-nodegroups --cluster-name $clusterName --region $region --query 'nodegroups' --output text)
  # Time complexity = O(n^3)
  for nodeGroup in $nodeGroups; do
    autoScalings=$(aws eks describe-nodegroup --cluster-name $clusterName --nodegroup-name $nodeGroup --region $region --query 'nodegroup.resources.autoScalingGroups[0]' --output text)
    for KEY in "${!autoScalings[@]}"; do
      echo "Start tagging ${autoScalings[$KEY]}"
      # it's to read from text file
      while read -r line;
      do
        # for new instance spawning
        asg=$(aws autoscaling create-or-update-tags --region $region --tags ResourceId=${autoScalings[$KEY]},ResourceType=auto-scaling-group,${line},PropagateAtLaunch=true ResourceId=${autoScalings[$KEY]},ResourceType=auto-scaling-group,PropagateAtLaunch=true)
        # existing instances
        instances=$(aws autoscaling describe-auto-scaling-groups --auto-scaling-group-name ${autoScalings[$KEY]} --query 'AutoScalingGroups[*].Instances[*].InstanceId' --output text --region $region)
        for instance in $instances; do
          command=$(aws ec2 create-tags --resources $instance --tags ${line} --region $region)
        done
      done < "$input"
      echo "Done tagging ${autoScalings[$KEY]}"
    done
  done
}

tagCluster $ARGS