portforward does not work when pod is using host network

[qiujian16]

In our environment, we start tiller server with host network. We then connect to tiller with portforward using helm list. And an error returns

E0417 05:02:29.988555   22051 portforward.go:331] an error occurred forwarding 34086 -> 44134: error forwarding port 44134 to pod 6b79d2ed658ad32c0719b807e83f3fce882fc7271a28047ca3e21a6cc65b6e30, uid : network namespace for sandbox "6b79d2ed658ad32c0719b807e83f3fce882fc7271a28047ca3e21a6cc65b6e30" is closed

I think the check here https://github.com/containerd/cri/blob/master/pkg/server/sandbox_portforward.go#L57 fails. If a pod uses host network, I guess the network namespace will not be created?

[Random-Liu]

@qiujian16 Good catch!