Did you try the Kubernetes Operator: https://github.com/arangodb/kube-arangodb? Should at least help with the k8s part... Also would be curious about your sharding challenges, feel free to ping me on the ArangoDB slack
I ended up using the somewhat deprecated community-made .yaml files in https://github.com/sbaugher/arangodb-kubernetes
It has a problem of it's own, but I have some idea how to fix it (next time it happens), and am very interested in Oasis.