Make it possible to disable overlay and overlay2 separately.
With this commit, we now have `exclude_graphdriver_overlay` and
`exclude_graphdriver_overlay2` build tags for the engine, which
is in line with any other graph driver.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Static build with devmapper is impossible now since libudev is required
and no static version of libudev is available (as static libraries are
not supported by systemd which udev is part of).
This should not hurt anyone as "[t]he primary user of static builds
is the Editions, and docker in docker via the containers, and none
of those use device mapper".
Also, since the need for static libdevmapper is gone, there is no need
to self-compile libdevmapper -- let's use the one from Debian Stretch.
Signed-off-by: Kir Kolyshkin <kolyshkin@gmail.com>
Adds a new overlay driver which uses multiple lower directories to create the union fs.
Additionally it uses symlinks and relative mount paths to allow a depth of 128 and stay within the mount page size limit.
Diffs and done directly over a single directory allowing diffs to be done efficiently and without the need fo the naive diff driver.
Signed-off-by: Derek McGowan <derek@mcgstyle.net> (github: dmcgowan)
