This imperative Jenkinsfile will dynamically create nodes and commands that will be ran in parallel reference impl

ParallelNodeProvisionJenkinsfile

/**
 * @Author Chris Maggiulli
 *
 * This is an imperative ( scripted ) Jenkinsfile which will dynamically create nodes and run them in parallel.  Modify the List of Hashmaps
 * to include the name of the node and the command you wish to run.
 *
 **/
node('master') {
    stage('orchestration') {
        
        dynamicStages = [:]
        def nodesCommandList = [ [name:"sqlplus", command:"ls -ltra"], [name:"jdk11", command:"echo hello"] ]
        
        nodesCommandList.each{ nodeCommand ->
	/*
	 * This creates a map of closures that represent a node
	 * The node closure is the value of the map
	 * This is used to dynamically create parallel nodes
	 */
            dynamicStages["${nodeCommand['name']}"] = {
                node {
                    stage("${nodeCommand['name']}") {
                        sh "${nodeCommand['command']}"
                    }
                }
            }
        }
      
        parallel dynamicStages
    }
}