Anything that is robust, dynamic, with a big ecosystem. Python, Ruby, whatever have you. You don't need raw speed since the OS API does most of the work, and the ease of programming would make it more productive. In the end, they added Python anyway for stuff like "compose", so I'm missing the point of using Go for this. The Go code is not even network bound, the ability to get multicore easily is not a bit advantage here since you spawn a new process anyway, so really, why ?
Go has much lower memory usage, high throughput, std ssl/tls/http libraries, high performance GC and produce fully static binaries. I do not think Python/Ruby can provide required performance for containers, cluster scheduling, orchestration etc. Even Java with much higher perf compared to Python/Ruby is not suitable because of high memory usage.
> lower memory usage, high throughput [...] high performance GC
Irrelevant, as most ressources will be consummed from underlying OS API.
> std ssl/tls/http libraries
So does Python and Ruby. But even if it didn't, you provide a package anyway.
> produce fully static binaries
You can do that with Python and nuikta. But there is need for it, since docker is provided as an msi/deb/whatever that take care of distribution.
> high memory usage.
On your xGb RAM server, the memory usage of your container is the least of your problem. Your DB will dwarf it, your app will dwarf it. Anything you put in your containers will take 100 times more memory.
Ocaml is a good choice, and Anil Madhavapeddy used it for his unikernel ideas. But Ocaml doesn't have strong backing any more. JaneStreet alone isn't enough.
