The :ro option can only be used for named and bind-mounted volumes, not on "regular" (unnamed) volumes as explained in https://github.com/docker/docker/pull/16013#issuecomment-146647216 The example in the documentation actually resulted in a bind-mounted volume, mounted at "ro" inside the container. This removes the incorrect example from the documentation. Signed-off-by: Sebastiaan van Stijn <github@gone.nl> Upstream-commit: 244d9c337034b0db030c05189ca8eb2323d92c61 Component: engine