Deployment doesn't update containers

[needl3]

As we push new changes and new image gets pushed to container registry, new container instance with same name however doesn't spawn by itself. As the docs say, this is intended feature so we have to first delete that container instance and then redeploy with new image. However this arises new problem of not being sure if the new container actually responds to requests or not i.e successfully deploys without any service degradation. To cope with this problem we have to check if some common requests are handled by newly spawned container instance. If not, we have to revert to previously running container. However this still will cut the service off some minutes while it validates.