in order to test your app in prod-like env you need to run prod-like env locally. ie. a k8s-cluster that is close enough to prod. for that you will have to at least simulate multi-node-setup and run all cluster-addons like in production.
i am excited about this move from docker but i don't think it will solve all the problems. i think once you have a bigger team it is worthwhile to run a second k8s-cluster besides prod where people can just test things on it. otherwise it is actually not that hard to run a local k8s-cluster with vagrant, not sure how docker wants to top that - i think there is no need to top vagrant.
i am excited about this move from docker but i don't think it will solve all the problems. i think once you have a bigger team it is worthwhile to run a second k8s-cluster besides prod where people can just test things on it. otherwise it is actually not that hard to run a local k8s-cluster with vagrant, not sure how docker wants to top that - i think there is no need to top vagrant.