I am sad to see fleet go. Fleet was quiet simple to setup but k8s was a monster. They have so much terminology and it tries to cover all the cases of cloud orchestration. I think my fallback now is Swarm (hope it gets more stable though)
My shortcut was using https://github.com/kubernetes-incubator/kompose to convert my docker-compose.yml to the equivalent K8S objects. It wasn't as simple as just running it, but it let me see what it would basically take to do the same thing in Kubernetes. It ended up taking just a few days to wrap my head around it all and get it up and running. Probably even easier if you use something like GKE which manages the cluster for you. If you're investing in using containers for the long-haul, I think it's definitely worth the learning overhead.
There are only three key object types you need to understand to start using K8S: Deployments, Pods & Services. Feel free to msg me if you have some questions about getting started.
Thankfully, that is changing with things like minikube, kubeadm, kops, and self hosted Kube.
I think the orchestration wars are essentially over. Kube has insane momentum, and is a well architected solution.
To be clear I'm not saying there aren't deployments where the complexity of something like kubernetes isn't necessary.
But most people only run a small number of servers. I'd argue most clusters people are deploying are going to stay below 10 servers for their entire lifetime, and a dozen or two services that generally tends to need basic high availability and load balancing and 1-3 different data stores with replication/data persistence requirements. For that kind of setup, while you certainly can run kubernetes, the complexity of it simply isn't needed.