Incompatible with GKE Ingress without k8s 1.17 + BackendConfig

[radicaled]

You cannot expose an ArangoDB database cluster (specifically the coordinators) through a GKE Ingress on k8s 1.16.

As documented here, GKE Ingress only supports HTTP readiness probes. Therefore, in k8s 1.16, you cannot expose a service backed by ArangoDB coordinators through an ingress, as their readiness probes are some command-line executable. k8s 1.17 offers an alternative mechanism, but requires knowing exactly what endpoint on a coordinator will return a 200 OK code.

I believe this should be documented, as it was unexpected to discover that coordinators don't use HTTP readiness probes even though their interface is exposed through HTTP!