Brian Goff
a19065e951
It's a common scenario for admins and/or monitoring applications to mount in the daemon root dir into a container. When doing so all mounts get coppied into the container, often with private references. This can prevent removal of a container due to the various mounts that must be configured before a container is started (for example, for shared /dev/shm, or secrets) being leaked into another namespace, usually with private references. This is particularly problematic on older kernels (e.g. RHEL < 7.4) where a mount may be active in another namespace and attempting to remove a mountpoint which is active in another namespace fails. This change moves all container resource mounts into a common directory so that the directory can be made unbindable. What this does is prevents sub-mounts of this new directory from leaking into other namespaces when mounted with `rbind`... which is how all binds are handled for containers. Signed-off-by: Brian Goff <cpuguy83@gmail.com> Upstream-commit: eaa5192856c1ad09614318e88030554b96bb6e81 Component: engine