Information
https://docs.docker.com/engine/reference/commandline/run/#/run
2.https://events.linuxfoundation.org/sites/events/files/slides/User%20Namespaces%20-%20ContainerCon%202015%20-%2016-9-final_0.pdf
3.https://github.com/docker/docker/pull/12648
Solution
Do not share user namespaces between host and containers.Impact-NoneDefault Value-By default, the host user namespace is shared with the containers until user namespace
support is enabled.