pipeline {
    agent {
        kubernetes {
            inheritFrom 'default'
            yamlMergeStrategy: merge(),
            yaml """
spec:
    hostAliases:
      - ip: 10.0.0.1
        hostnames:
          - some.virtualized.service.company.com
"""
        }
    }

    stages {
        stage('Main') {
            steps {
                script {
                    # Better to see build logs with generated YAML
                    sh 'cat /etc/hosts'
                }
            }
        }
    }
}