This implements support for mounting and unmounting volumes backed by volume plugins. Support for actually retrieving plugins requires a pull request to land in containers.conf and then that to be vendored, and as such is not yet ready. Given this, this code is only compile tested. However, the code for everything past retrieving the plugin has been written - there is support for creating, removing, mounting, and unmounting volumes, which should allow full functionality once the c/common PR is merged. A major change is the signature of the MountPoint function for volumes, which now, by necessity, returns an error. Named volumes managed by a plugin do not have a mountpoint we control; instead, it is managed entirely by the plugin. As such, we need to cache the path in the DB, and calls to retrieve it now need to access the DB (and may fail as such). Notably absent is support for SELinux relabelling and chowning these volumes. Given that we don't manage the mountpoint for these volumes, I am extremely reluctant to try and modify it - we could easily break the plugin trying to chown or relabel it. Also, we had no less than *5* separate implementations of inspecting a volume floating around in pkg/infra/abi and pkg/api/handlers/libpod. And none of them used volume.Inspect(), the only correct way of inspecting volumes. Remove them all and consolidate to using the correct way. Compat API is likely still doing things the wrong way, but that is an issue for another day. Fixes #4304 Signed-off-by: Matthew Heon <matthew.heon@pm.me>
2.4 KiB
% podman-volume-create(1)
NAME
podman-volume-create - Create a new volume
SYNOPSIS
podman volume create [options]
DESCRIPTION
Creates an empty volume and prepares it to be used by containers. The volume can be created with a specific name, if a name is not given a random name is generated. You can add metadata to the volume by using the --label flag and driver options can be set using the --opt flag.
OPTIONS
--driver=driver
Specify the volume driver name (default local). Setting this to a value other than local Podman will attempt to create the volume using a volume plugin with the given name. Such plugins must be defined in the volume_plugins section of the containers.conf(5) configuration file.
--help
Print usage statement
--label=label, -l
Set metadata for a volume (e.g., --label mykey=value).
--opt=option, -o
Set driver specific options.
For the default driver, local, this allows a volume to be configured to mount a filesystem on the host.
For the local
driver the following options are supported: type
, device
, and o
.
The type
option sets the type of the filesystem to be mounted, and is equivalent to the -t
flag to mount(8).
The device
option sets the device to be mounted, and is equivalent to the device
argument to mount(8).
The o
option sets options for the mount, and is equivalent to the -o
flag to mount(8) with two exceptions.
The o
option supports uid
and gid
options to set the UID and GID of the created volume that are not normally supported by mount(8).
Using volume options with the local driver requires root privileges.
When not using the local driver, the given options will be passed directly to the volume plugin. In this case, supported options will be dictated by the plugin in question, not Podman.
EXAMPLES
$ podman volume create myvol
$ podman volume create
$ podman volume create --label foo=bar myvol
# podman volume create --opt device=tmpfs --opt type=tmpfs --opt o=nodev,noexec myvol
# podman volume create --opt device=tmpfs --opt type=tmpfs --opt o=uid=1000,gid=1000 testvol
SEE ALSO
podman-volume(1), mount(8), containers.conf(5)
HISTORY
January 2020, updated with information on volume plugins by Matthew Heon mheon@redhat.com November 2018, Originally compiled by Urvashi Mohnani umohnani@redhat.com