Viktor Saienko developed a targeted feature for the major/cloud-init repository, focusing on enhancing network configuration reliability for cloud deployments. He implemented the ability to set MAC addresses on VLAN subinterfaces, addressing a regression where these addresses were not properly propagated to netplan. Using Python and leveraging his expertise in cloud infrastructure and network configuration, Viktor updated both the codebase and documentation to support the new mac_address field. He also expanded test coverage to ensure robust deployment stability. This work improved automation reliability for VLAN networking, reducing post-deployment issues and contributing to more consistent network interface behavior across cloud instances.