Description of problem

The proxy does not know (afaict) which sandbox/container it is routing, and thus cannot annotate any logs it generates.

Expected result

It might aid debugging if we can add the annotation. For instance, on an agent yamux fail, I got:

time="2018-07-02T11:49:16.217469645+01:00" level=info msg="2018/07/02 10:49:16 [ERR] yamux: keepalive failed: i/o deadline reached\n" name=kata-proxy pid=25683 source=agent

routed out by https://github.com/kata-containers/proxy/blob/master/proxy.go#L187, but it does not indicate which sandbox/container it relates to, and that information is currently not to hand in the proxy.

I think the only way to do this is to pass the sandbox ID in over at https://github.com/kata-containers/runtime/blob/master/virtcontainers/kata_proxy.go#L41 on the proxy invocation command line.