Industrial systems are increasingly dominated by software. In addition, this software is distributed across several compute domains, from decentralized edge to centralized datacenters and clouds. While software lifecycle management has tremendously improved in the area of cloud computing, there is no homogeneous and seamless environment to build, deploy and operate software across these domains. This leads to a separation, inefficient processes, and increased efforts in providing software that runs across the different layers. This paper introduces the concept of seamless computing, which provides a homogeneous computing environment for multi-domain applications, supporting the mobility of workloads between cloud and edge. The approach is based on transferring established, de-facto standard cloud computing technologies to resource-constrained compute environments in the edge. After defining high-level requirements for seamless computing, a functional reference model is proposed, and existing cloud technologies are discussed. Finally, a concept and results of an implementation of seamless computing using container orchestration are presented and discussed.