pipeline {     
  stage('Some stage') {         
     steps {             
        script {                 
            def awsActions[]                 
            awsActions['ec2_A'] = { awsFunc('ec2_A') }
            awsActions['ec2_B'] = { awsFunc('ec2_B') }                 
            awsActions['ec2_C'] = { awsFunc('ec2_C') }
            parallel awsActions
         }         
      } 
   } 
} 

def awsFunc(ec2) {     
   def counter = 0
   def id
   while (counter < 5 && conditionNotMet) {
      id = run aws command to getinstance id ${ec2}         
      counter++         
      echo "counter = ${counter}"
      echo "id = ${id}"     
   } 
}