The main responsibilities of an infrastructure engineer are: 1. Design, deploy, and manage cloud infrastructure based on AWS/GCP/Alibaba Cloud. 2. Implement and manage containerization using Docker. 3. Organize and manage Kubernetes clusters. 4. Develop and maintain Infrastructure as Code (IaC) using tools such as Terraform or CloudFormation. 5. Automated infrastructure deployment and management processes. 6. Monitor system performance, troubleshoot, and optimize infrastructure to achieve optimal efficiency. 7. Collaborate with the development team to ensure smooth integration and deployment of the application. 8. Implement and manage the CI/CD pipeline.