Most apps running on Google servers are aware that they're running in a shared environment, so they don't need the overhead of virtualized network interfaces. So I doubt that there will be any specific support for network namespaces.
And you can approximate mount namespaces with chroots and bind mounts. (In some ways that's better, since it's a bit easier for a process outside the container to interact with the container's filesystem).
Damn. This means it's much less useful to me (and 99% of applications outside of google). I guess I could combine lmctfy with a namespacing library of my own. But that's more extra work than I was anticipating.
And you can approximate mount namespaces with chroots and bind mounts. (In some ways that's better, since it's a bit easier for a process outside the container to interact with the container's filesystem).