This persists the "propagated mount" for plugins outside the main
rootfs. This enables `docker plugin upgrade` to not remove potentially
important data during upgrade rather than forcing plugin authors to hard
code a host path to persist data to.
Also migrates old plugins that have a propagated mount which is in the
rootfs on daemon startup.
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
(cherry picked from commit e8307b868d)
Signed-off-by: Brian Goff <cpuguy83@gmail.com>
Signed-off-by: Victor Vieux <vieux@docker.com>
(cherry picked from commit bcead9282e)
Signed-off-by: Victor Vieux <vieux@docker.com>
Signed-off-by: Vincent Demeester <vincent@sbr.pm>
Legacy plugins expect host-relative paths (such as for Volume.Mount).
However, a containerized plugin cannot respond with a host-relative
path. Therefore, this commit modifies new volume plugins' paths in Mount
and List to prepend the container's rootfs path.
This introduces a new PropagatedMount field in the Plugin Config.
When it is set for volume plugins, RootfsPropagation is set to rshared
and the path specified by PropagatedMount is bind-mounted with rshared
prior to launching the container. This is so that the daemon code can
access the paths returned by the plugin from the host mount namespace.
Signed-off-by: Tibor Vass <tibor@docker.com>
(cherry picked from commit c54b717caf)
Signed-off-by: Victor Vieux <vieux@docker.com>
