.. _volumes:
=======
Volumes
=======
Volumes in lithos are just some kind of mount-points. The mount points are not
created by ``lithos`` itself. So they must exist either in original image. Or
on respective volume (if mount point is inside a volume).
There are the following kinds of volumes:
.. volume:: Readonly
Example: ``!Readonly "/path/to/dir"``
A **read-only** bind mount for some dir. The directory is mounted with
``ro,nosuid,noexec,nodev``
.. volume:: Persistent
Example: ``!Persistent { path: /path/to/dir, mkdir: false, mode: 0o700, user: 0, group: 0 }``
A **writeable** bind mount. The directory is mounted with
``rw,nosuid,noexec,nodev``. If you need directory to be created set
``mkdir`` to ``true``. You also probably need to customize either the user
(to the one running command e.g. same as ``user-id`` of the container) or
the mode (to something like ``0o1777``, i.e. sticky writable by anyone).
.. volume:: Statedir
Example: ``!Statedir { path: /, mode: 0o700, user: 0, group: 0 }``
Mount subdir of the container's own state directory. This directory is
used to store generated ``resolv.conf`` and ``hosts`` files as well as for
other kinds of small state which is dropped when container dies. If you
mount something other than ``/`` you should custimize mode or an owner
similarly to ``!Persistent`` volumes (except that you can't create statedir
subdirectory by hand because statedir is created for each process at start)
.. volume:: Tmpfs
Example: ``!Tmpfs { size: 100Mi, mode: 0o766 }``
The tmpfs mount point. Currently only ``size`` and ``mode`` options
supported. Note that syntax of size and mode is generic syntax for
numbers for our configuration library, not the syntax supported by kernel.