A network service may be supported by a software application that is executed by multiple computer servers, such as servers that are maintained as part of a server pool. To migrate to a container-based platform, the software application is containerized to create a container image. A container cluster is then created based on the container image. The container cluster includes one or more executing containers, each of which performs the functions of the software application. The container cluster is then added as a member of the server pool to receive a portion of any network requests for the network service. Computer servers of the server pool may then be removed gradually, over time, to let the container cluster gradually assume responsibility for responding to network requests.