Jenkins pipeline with multiple agents

How to run multiple agents on a single jenkins pipeline

set agent to none

inside each stage define desired agent

see an example below

properties([
  parameters([
    string(name: 'GERRIT_REFSPEC'),
  ])
])

def get_yaml() {
  node {
    sh 'env'
    echo GERRIT_PATCHSET_REVISION
    echo "${GERRIT_PATCHSET_REVISION}" 
    return """
apiVersion: v1
kind: Pod
metadata:
  labels:
    some-label: some-label-value
spec:
  containers:
  - name: simplekube
    image: dhub.net/jenkins/simplekube:${GERRIT_PATCHSET_REVISION}
    command:
    - cat
    tty: true
    securityContext:
      runAsUser: 0
    """
  }
}


pipeline {
  environment {
    VIRTUAL_USERS = 40000
    TEST_SCRIPT = '/scenarios/login.js'
    YAML_FILE = get_yaml()
  }

  agent none

  stages {
    stage('Build docker image and push to dhub') {
      agent { label 'docker' }
        steps {
        sh '''
          git checkout ${GIT_REF}
          image_with_tag="dhub.net/jenkins/simplekube:$(git rev-parse HEAD)"
          docker build --pull -t simplekube:latest -t "$image_with_tag" --build-arg GIT_DESCRIBE=$(git rev-parse HEAD) ./jenkins_k8s/.
          docker tag "$image_with_tag" "$image_with_tag"
          docker push "$image_with_tag"
          '''
        }
    }

    stage('Performance Test') {
      agent {
        kubernetes {
          yaml env.YAML_FILE
        }
      }

      steps {
        script {
          def stages = [: ]
          int pod_count = env.VIRTUAL_USERS.toInteger()/10000
          for (int i = 0; i < pod_count; i++) {
            stages[i] = {
              // node('k6node') { // request for dedicate node for k6 tests (consistent load generation)
                stage("Stage-${i}") {
                  container('simplekube') {
                    sh 'k6 version'
                    sh 'k6 run /scenarios/login.js'
                  }
                }
              // }
            }
          }
          parallel stages
        }
      }
    }
  }
}